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Open Access Article
1 - Synthesis, structural and optical properties of pure ZnO and Co doped ZnO nanoparticles prepared by the co-precipitation method
P. Geetha Devi A. Sakthi Velu -
Open Access Article
2 - The comparison synthesis of CuNiO2 nanoparticles prepared by sol-gel auto-combu on, microwave and co-precipitation techniques
S. A. Khorrami N. Naderfa M. G. G Mojadad -
Open Access Article
3 - Temporal-Spatial Analysis of Rainfall Days Frequency Trend of Western Iran Regions
شهاب شفیعی غلامعلی مظفریPrecipitation including climatic elements in the dimension of time and space changes a lot. In the study of extreme precipitation because of the devastating effect it is of great importance. The aim of this study is to identify and analyze theslope of the western region MorePrecipitation including climatic elements in the dimension of time and space changes a lot. In the study of extreme precipitation because of the devastating effect it is of great importance. The aim of this study is to identify and analyze theslope of the western regions of extreme precipitation, which is to achieve this goalprecipitation data of 69 synoptic stations and climate (province of Kerman, Kermanshah, Hamedan, Ilam, Lorestan and Kurdistan), in during the statistical period (2010-1961) were used and the annual threshold of extreme precipitation West generalized method of distributing a limit to the western regions of the country to 22 mm respectively. The extreme precipitation for each month during the period under study western regions using Mann-Kendall method identified and analyzed. and in December this increase was observed in the western half of Kermanshah province and in February this positive trend observed in the northwestern province of Kurdistan conceptual framework, these areas are consistent with the Zagros mountains. Manuscript profile -
Open Access Article
4 - Assessing the heavy spring rains and the earth outgoing long wave radiation, Case Study: North West of precipitation 15 April 2016
ali ghaffari محمد سلیقه محمدحسین ناصرزادهThe purpose of this study is assessing the spring precipitation and outgoing long wave radiation using Reviews Climate maps at different levels of the atmosphere, surface and Earth mapping reflecting long-wavelength radiation. For these data synoptic stations of the Nor MoreThe purpose of this study is assessing the spring precipitation and outgoing long wave radiation using Reviews Climate maps at different levels of the atmosphere, surface and Earth mapping reflecting long-wavelength radiation. For these data synoptic stations of the North West (15 April 2016) was obtained from the meteorological. The data from the induction by NCEP-resolution grid of horizontal 5 degrees of length and width of geographic and through the application Grads, maps of sea level, the 500 hpa daily, Vorticity 700 hpa, map convergence and divergence flow of moisture , long wavelength reflectance map of the earth's surface, atmosphere and map omega vertical advection map queries. Reviews maps indicate that the main cause of precipitation North West of Iran on 26 April, entry system, the rainfall from Eastern Europe and accompanying Western air mass with this system, and the effect of convection locally in the morning because of high levels of outgoing long wave earth is very minimal, but in the afternoon the existence of the local convection has intensified and the highest precipitation occurred in the study Manuscript profile -
Open Access Article
5 - Investigation and identification of synoptic patterns of pervasive and destructive floods in Iran
Ali Hanafi Vali AsfandyarIran has different rainfall conditions due to special geographical conditions and location, so that despite having a rainfall equal to one third of the global average rainfall, there is a sharp fluctuation in the rainfall regime. The purpose of this study is to investig MoreIran has different rainfall conditions due to special geographical conditions and location, so that despite having a rainfall equal to one third of the global average rainfall, there is a sharp fluctuation in the rainfall regime. The purpose of this study is to investigate and identify the synoptic patterns of flood and destructive precipitation moles in the period 24 to 27 March 2019. For this purpose, daily precipitation data for 100 synoptic stations in the country that had significant rainfall during this period were obtained and analyzed from the Meteorological Organization. A level of 850 hPa was obtained from the site of the US National Center for Atmospheric and its maps were prepared and analyzed using Grads software. The results of the analysis of synoptic maps showed that in the study period, except for the northwestern region of Iran, the rest of the country was affected by a low pressure system of Mediterranean origin. The stretching of the Siberian high-pressure tongue on the Caspian Sea and the north of the country has created a pressure pattern on the border between the two air masses and has prevented it from spreading to the northwest. Also, the passage of this system over the Red Sea, the Persian Gulf and the Sea of Oman and the proper moisture supply by them, has greatly increased its instabilities. The intensity of rainfall in some stations has been such that the total rainfall of this period has been half the average annual rainfall of that station. Manuscript profile -
Open Access Article
6 - Analysis and forecasting of precipitation in the Larestan area by Markov chain.
بهلول Alijani زین العابدین Jafarpoor حیدر GhaderiIn order to analyze the precipitation of the Larestan area, the rain days with 0.1millimeter or more were obtained from the Iranian Meteorological Organization for the1960-2003 period. First the rainy periods with different lengths were identified andtheir monthly and s MoreIn order to analyze the precipitation of the Larestan area, the rain days with 0.1millimeter or more were obtained from the Iranian Meteorological Organization for the1960-2003 period. First the rainy periods with different lengths were identified andtheir monthly and seasonal frequencies were calculated. On the monthly basis Januaryhad the highest wet days frequency and winter was the wettest but the spring was thedriest season. The wettest year had 44 rain days while only 11 days were experiencedduring the dry year. The mean daily density of rain was 8.2 mm and the mean timeinterval between successive rainy periods was 6.2 days. On the average the rainyperiod begins each year on 8 of December and ends on 6 of April.The first order Markov chain was applied to the data series to forecast the wetperiods. The model responded well and was able to forecast significantly andprecisely. The model was fitted best for the runs of one to six days proving thehypothesis of the study. Manuscript profile -
Open Access Article
7 - Identify suitable natural sites collect precipitation using geographical Information System Case study: Birjand Plain
M.H NamiIn dry areas, like the vast majority of our country, people have always been and are facing a shortage of water. The possibility of increasing the available water is very limited. The shortage for combating it should be managed more on conservation and optimal utilizati MoreIn dry areas, like the vast majority of our country, people have always been and are facing a shortage of water. The possibility of increasing the available water is very limited. The shortage for combating it should be managed more on conservation and optimal utilization of the note. Identify suitable locations to collect runoff important step toward increasing access to water and fertile soil in the area is semi-desert. In this paper, in order to prone areas collect runoff plain Birjand, GIS is used. To power part of the basin runoff by considering factors such as the spatial variability of soil, land use, rainfall and slope produced and then a layer in GIS to collect runoff potential locations were identified. The ability to collect runoff in 4 levels: poor, moderate, good, very good was defined respectively 28.38, 48.9, 20.91 and 3.7% of the area into account. The water storage capacity in a very good area with storage capacity has been studied and results are discussed in three different modes embankment. Manuscript profile -
Open Access Article
8 - Study of Arctic Oscillation Effect on Temperature and Precipitation Fluctuations at Winter in Central Iran
K. Omidvar M. JafarinadoshanAim of this research is to predict the fluctuations of winter (December-March) temperature and precipitation in central Iran using Tele-connection patterns. The applied data is included the Arctic Oscillation index and daily temperature (minimum , maximum and average) a MoreAim of this research is to predict the fluctuations of winter (December-March) temperature and precipitation in central Iran using Tele-connection patterns. The applied data is included the Arctic Oscillation index and daily temperature (minimum , maximum and average) and precipitation values during 45 years ( 1965-2010) in 9 stations in central Iran. After averaging the data, seasonal time series was made separately for each variable. The results of the correlation test revealed that winter temperature is decreased in central Iran in positive phase of Arctic Oscillation. Also, it was cleared that AO variations in autumn justify 25% of winter temperature variations in the under studying zone. Because of lack of significant correlation coefficients in the most under studying stations, we can conclude that there is not any relationship between Arctic Oscillation and winter precipitation in central Iran. Manuscript profile -
Open Access Article
9 - The Clarification of Monthly Precipitation Fluctuations in Ahar Station in relation to the Tele-connection Patterns
Ali Mohammad Khorshiddoust Yousef Ghavidel RahimiAuthors have studied the precipitation fluctuations and rainfall changes inAhar synoptic station in this paper, applying long term monthly records for the47 year period (1960-2006). Results of using Man-Kendal test indicatesignificant correlation between precipitation c MoreAuthors have studied the precipitation fluctuations and rainfall changes inAhar synoptic station in this paper, applying long term monthly records for the47 year period (1960-2006). Results of using Man-Kendal test indicatesignificant correlation between precipitation changes and tele-connectionpatterns in the study area. With regard to this matter, the relationship of autumnprecipitation with El-Nino atmospheric-oceanic pattern (so-called ENSO) duringwarm phase increases precipitation and the same linkages with La-Nina duringcold phases enhances droughts. The correlation of winter precipitation with teleconnectionpatterns of Northern Atlantic and Arctic Ocean has been alsosignificant in such a way that during the North Atlantic negative phases themagnitude of incoming cyclones to the area creates higher rates and on the otherhand, in positive phase causes a decrease in precipitation due to the dominanceof Azure Anticyclone. Testing of Standardized Precipitation Indexes (SPI) forevaluating monthly wet and dry periods also indicates that the occasionaloccurrence of drought periods in the area is irreversible. The independence ofmonthly wet and dry periods is also one of the main results of this study. Manuscript profile -
Open Access Article
10 - Study of the Likelihood of Climate change in Kerman Province Using Man – Kendall Method (Case Study: Kerman Station)
بتول BahakClimate change is one of the major challenges faced by man in the current age. Phenomena such as precipitation changes, global warmness, melting of polar ices, flood, unexpected and severe coldness and warmness in most parts of the world are so severe, damaging and stre MoreClimate change is one of the major challenges faced by man in the current age. Phenomena such as precipitation changes, global warmness, melting of polar ices, flood, unexpected and severe coldness and warmness in most parts of the world are so severe, damaging and stressful that have resulted in climate change to be at the top of the studies of climatic sciences researchers and extensive international, regional and local studies have already addressed that. In order to review the possibility of climate change in Kerman Province, precipitation average, minimum, average and maximum temperatures of synoptic station in Kerman during 1956-2005 were received from the website of meteorology organization and was adjusted in terms of time series and was then studied by using Man – Kendall test. In this research, type and time of changes in the aforesaid elements were identified by using the above model. The results obtained from the analyses indicate that commencement time of most changes is sudden and of both trend and fluctuation types. precipitation changes in warm months is considerable while minimum, average and maximum temperatures in April, November and December were more considerable. No significant changes are observed in other months. On the whole, precipitation in the station during the period of study decreased and average, minimum and maximum temperatures increased. Manuscript profile -
Open Access Article
11 - Assess the drought situation in Kashan desert of Kashan and Aran ShhrstanHay Bidgol (NushaBad) using the Standardized Precipitation Index (SPI)
Amir Fakhrabadi ALIREZA ENTEZARY Omolbanin BazErafshanDrought is creeping phenomenon, which affects and threatening human life. Drought in a period of unusually dry weather that lack enough water to cause hydrological imbalance faces define. Drought is studied in four main characteristics include intensity, duration, frequ MoreDrought is creeping phenomenon, which affects and threatening human life. Drought in a period of unusually dry weather that lack enough water to cause hydrological imbalance faces define. Drought is studied in four main characteristics include intensity, duration, frequency and areal extent. The aim of this study is mapping the intensity of droughts in Kashan. For this purpose, the Standardized Precipitation Index (SPI) as an indicator for drought monitoring stations located in the plains of the period of 20 years (1390-1369) in the time scale 3,6,9,12,24 and 48 months were used. The most frequent drought in 24 months and the most comprehensive range of acute and severe drought in the plains. SPI values for the severe drought in the province timescales for geostatistics techniques and were classified image. The maps show the extent of the drought and the reduced by increasing the time scale drought in the plains of the West to the East increased. Manuscript profile -
Open Access Article
12 - Coordinatin of subtropical-pressure centers in flood-rains of the south and south-easthern Iran. Case study: The rainfall of july 1976
محمد SalighehIran's southern half's climatic have especially features, is its summery rainfalls amongwhich the long–term rain of July 1976 has had a unique specialty as studied till now.In this period, there was coordination between the atmospheric cycles of low latitudes(seas MoreIran's southern half's climatic have especially features, is its summery rainfalls amongwhich the long–term rain of July 1976 has had a unique specialty as studied till now.In this period, there was coordination between the atmospheric cycles of low latitudes(seasonal spring) and mid latitudes (tropic adjoined-high pressure recycling).Thepresent study shows that the coordination of these pressure systems resulted in stringthing and intensifying the moisture penetrate from eastern side towards the site ofstudy. The coordination between these two systems in the south of Himalayas createda sort of convergency, therefore eastern and western flows of polar edge of seasonalcell have moved with higher speed. This velocity increasing make the system able tosend more moisture to Iran's south and southern east region. Moreover, the rainfallneeds elevating factors. These factor are created at a time when elevating conditionsare provided by atmosphere middle levels. Researches shows that when tropicaladjoined-high pressures transfer to higher levels, the opportunity for local sweepingselevating, will increase and precipitation will occur. Manuscript profile -
Open Access Article
13 - Spatial Analysis of probable maximum precipitation in Iran
Seyed Jamalodin Daryabari Hossein Mohammadi Gholam Hossein RezaeiProbable maximum precipitation (PMP) is a conceptual structure as the most intense rainfallto dam design, reservoirs and urban projects for our sets. The main goal of this study isdetermine the most probable precipitation and spatial analysis in Iran. Purpose of the 180 MoreProbable maximum precipitation (PMP) is a conceptual structure as the most intense rainfallto dam design, reservoirs and urban projects for our sets. The main goal of this study isdetermine the most probable precipitation and spatial analysis in Iran. Purpose of the 180synoptic stations in Iran, 94 stations have long-term statistics of rainfall (20-55 years) will beselected. Then, using statistical software such as excel and SPSS the amount was calculated.the method used for PMP is Hrshfyld. Finally, using GIS and KRGING we did spatialanalysis. Maps obtained from the maximum probable precipitation in the Iran indicates thatthe spatial distribution of annual precipitation in Iran is uneven. According to existing mapsProbable maximum precipitation related to the northern and southern Iran.thus PMP from the south coast of Iran to central of Iran decrease and from the central area tothe north coast increase. Manuscript profile -
Open Access Article
14 - Temporal variations of soil moisture in relation to precipitation and temperature under fallow and planted conditions in rainfed land
uones mazllom Aliabadi alireza vaezi jeafar nikbakhtSoil moisture (SM) is the major factor controlling plant growth particularly in rainfed lands. It varies due to the change of climatic parameters such as precipitation and air temperature and evaporation. This study was conducted to found climatic factor influencing soi MoreSoil moisture (SM) is the major factor controlling plant growth particularly in rainfed lands. It varies due to the change of climatic parameters such as precipitation and air temperature and evaporation. This study was conducted to found climatic factor influencing soil moisture under rainfed conditions. A field experiment with two cultivated conditions: under fallow and cultivated with winter wheat was designed in a rainfed land with 10% slope steepness in the University of Zanjan during growth period from 2016 to 2017. Toward this, six plant plots with 2m × 5m dimensions were installed along the slope orientation similar to conventional tillage method in the area. Volumetric soil moisture was measured in 7-day interval using TDR model IDRG SMS-T2 set during growth period Climatic variables including air temperature (AT) and precipitation (P) along with soil temperature (ST) were determined during growth period. Based on the results, SM in cultivated plots was about 11% less than the follow plots, and this difference was statistically significant between the two. Amount of soil moisture significantly varied among different months (p<0.001). Significant correlations were found between SM and P, AT and ST in the two cultivation conditions (p<0.05). Higher dependency of SM on AT (r=0.44) and ST (r=0.51) was observed in fallow plots as compared to planted plots. This study revealed that ST is the most effective property controlling SM in fallow and planted lands in the area. Manuscript profile -
Open Access Article
15 - Bivariate Frequency Analysis of Rainfall Characteristics Using Archimedean Copula Functions (Case Study: Khanmirza Watershed in Chaharmahal and Bakhtiari Province)
Samira Moradzadeh Rahmatabadi Mohsen Irandost Rasoul MirabbasiBackground and Aim: This study aims to analyze the frequency of bivariate precipitation characteristics using Copula functions. for this purpose, daily rainfall data of Aloni station located in Khanmirza plain during the statistical period of 1986-2012 were used. After MoreBackground and Aim: This study aims to analyze the frequency of bivariate precipitation characteristics using Copula functions. for this purpose, daily rainfall data of Aloni station located in Khanmirza plain during the statistical period of 1986-2012 were used. After evaluating the rainfall events recorded at Aloni station in the study period (763 events), rainfall duration, rainfall depth, and then rainfall intensity of the events were calculated. Studies show that in the study area, usually rainfall events with an intensity of 5 mm/hr and more lead to floods, so in this study, the events that led to floods were selected to continue the calculations. Then, the common distributions in hydrology were fitted to each of the rainfall characteristics (duration, intensity, depth of rainfall) and the distributions that had the best fit to each of the rainfall characteristics were selected. Then, ten Copula functions were used to create a multivariate distribution of rainfall characteristics.Method: In this study, at first rainfall characteristics such as intensity, duration and depth were extracted for rainfall data leading to floods. Then the common margin distribution functions in hydrology were fitted to the characteristics. Then, after selecting the best margin distribution to create the cumulative distribution function (CDF) to create the multivariate distribution of rainfall characteristics, fitting the Copula functions of Clyton, Ali-Mikhaiel-Haq, Farli-Gumble-Morgan Stern, Frank, Galambos, Gamble-Hauggard, Placket, Filip-Gumble, Joe, and Gumble-Barnett on the mentioned variables were studied in pairs and for each pair of precipitation characteristics, the best Copula function was determined by comparing with the corresponding values of the empirical Copula. Then, using good criteria, the fit of the best Copula function for rainfall characteristics was determined. Since the condition for using Copula functions is the existence of a correlation between the studied features, so using Spearman, Pearson, and Kendall correlation coefficients, the correlation between the features was investigated also the cases of joint and conditional return periods, both probability and conditional and Kendall return period, which is basic concepts for analysis based on Copula functions, were evaluated.Results: The results of the analysis showed that the general extreme value distribution function (GEV) on rainfall characteristics (intensity, duration, depth) was known as the best distribution function and the results of the goodness of fit test showed that the Joe Copula function as The superior Copula function is based on the characteristics (intensity and duration) and (intensity and depth) and the Farli Gumble Morgan Stern Copula function was known as the superior Copula function on the depth and duration characteristics of rainfall. The results of both probability and conditional probability showed that when the flooding rainfall is 8 hours, the probability level will be 45 mm for the probability level of 0.2 and the probability of precipitation for the same level for the duration of is not necessary. It can be omitted15 hours. It will be 51 mm. The results of the Joint return period for “and” state showed that for the depth of rainfall of 60 mm and the intensity of rainfall of 60 mm/hr., the return period in the "and" state is less than 20 years. Based on the "or" mode for the same amount of intensity and depth of rainfall, the return period is less than 10 years (about 6 years). For a 25-year return period, provided the duration of the rainfall is 12.5 hours or more, the rainfall depth will be 75 mm.Conclusion: Based on the results of comparing the values of theoretical Copulas with the corresponding values of empirical probability, the Joe Copula function was recognized as the superior Copula function to create a bivariate distribution of rainfall intensity and depth characteristics, as well as a pair of rainfall intensity and duration characteristics. Farli- Gumble - Morgan Stern Copula had a better fit for rainfall duration and depth data. Then, using superior fitted Copula functions, useful information such as probabilistic and conditional probability as well as joint and conditional return periods were extracted. The maximum rainfall depth recorded at Aloni station was 114.7 mm and its duration was 14.40 hours. The seasonal "or" is 60 years old. The results of the joint and conditional return periods in this study have been widely used in hydrological and water resources studies, including flood risk analysis, drought, watershed management, and rangeland management. Manuscript profile -
Open Access Article
16 - Prediction of SPI drought index using support vector and multiple linear regressions
Saeed Samadianfard اسماعیل اسدیDrought is a natural phenomenon, which has a complex mechanism as a result of interactions of meteorological parameters and usually occurs in all climates. So, predicting drought indices and their chronological evaluation is an effective way for the drought management a MoreDrought is a natural phenomenon, which has a complex mechanism as a result of interactions of meteorological parameters and usually occurs in all climates. So, predicting drought indices and their chronological evaluation is an effective way for the drought management and adaptation with its consequences. In the current research, prediction of drought indices are carried out for Tabriz synoptic station, using support vector regression, multiple linear regression and standard precipitation index (SPI) for the time period of 1979 to 2012. In this regard, for predicting SPI indices in the periods of 3, 6, 9, 12, 24 and 48 months, six different input combinations including the antecedent correspondent values of the mentioned index have been utilized. The results of statistical analysis showed that both methods had significant accuracy. Nonetheless, the support vector regressions for predicting SPI-6, SPI-9 and SPI-24 had better performances, regarding the root mean squared errors of 0.4985, 0.4340 and 0.2427, respectively. However, the multiple linear regressions showed lower relative errors, for predicting SPI-3, SPI-12 and SPI-48. Meanwhile, it can be concluded that both examined methods including support vector and multiple linear regressions had acceptable predictions of drought index and can be used with an admissible confidentiality for the management of drought consequences. Manuscript profile -
Open Access Article
17 - Evaluation of high spatio-temporal resolution precipitation products over Dareh-Roud Ardebil basin
Alireza Pilpayeh Afshin Shayeghi Aydin Bakhtar Akbar Rahmati Afshin VatankhahInappropriate distribution of precipitation measurement stations has increased the use of gridded precipitation datasets consisting of satellite, reanalysis and ground- based datasets .Accurate measurement and estimation of precipitation amounts and events is very impor MoreInappropriate distribution of precipitation measurement stations has increased the use of gridded precipitation datasets consisting of satellite, reanalysis and ground- based datasets .Accurate measurement and estimation of precipitation amounts and events is very important. With the increasing development of satellite technologies in recent decades, access to high spatio- temporal resolution of precipitation data has been provided in many parts of the world. Given that these precipitation datasets cannot be used without initial assessment due to uncertainties in estimating cloud and precipitation thickness. The purpose of this study was to evaluate CMORPH, PERSIANN and PERSIANN-CDR precipitation datasets based on statistical indices such as contingency table indices at Dare-roud basin which is located in Ardabil province. Results show that CMORPH product performs better in estimating basin precipitation in most of the stations with RMSE index less than 3 mm and CC index higher than 0.7. Also in terms of the contingency table indices, the CMORPH performs better in most of the indices (except Bias) than other products, so it is recommended to correct its bias and use this precipitation product in future studies in Darehroud basin. Manuscript profile -
Open Access Article
18 - Investigating the Effect of Meteorological Parameters on Heavy Rainfall Events in Different Climates of Iran using Quantile Regression
Sedigheh Bararkhanpour Ahmadi Mohammad Ali Gholami Sefidkouhi Mojtaba KhoshraveshBackground and Aim: Climate changes caused by the progress and industrialization of human societies have caused changes in the intensity and frequency of heavy precipitation and floods, which have caused irreparable damages. In order to reduce these damages, it is neces MoreBackground and Aim: Climate changes caused by the progress and industrialization of human societies have caused changes in the intensity and frequency of heavy precipitation and floods, which have caused irreparable damages. In order to reduce these damages, it is necessary to identify the changes in the threshold values of precipitation and factors affecting it each region. Quantile regression methods are able to examine the trends not only in the median, but also in different ranges of the data series. Therefore, the purpose of this research is to investigate the seasonal trend of different amounts of precipitation and also to investigate the relationship between the climatic parameters of minimum temperature, maximum temperature, minimum relative humidity, maximum relative humidity and wind speed on different amounts of precipitation in different climates of Iran. Method: In the first step, the daily time series of climate data including precipitation, minimum and maximum temperature, minimum and maximum relative humidity and wind speed for a period of 45 years in different seasons for 5 synoptic stations of Babolsar, Shiraz, Bandar Abbas, Khorram Abad and Torbat Heydarieh were formed. In the selection of study stations, we tried to select stations with different climates and with appropriate statistical period. Then, to investigate the trend of seasonal changes of different amounts of precipitation in different quantiles (quantiles 0.01, 0.05, 0.1, 0.25, 0.5, 0.75, 0.9, 0.95 and 0.99) was analyzed using the quantile regression method in all study stations. In the next step, the relationship between the climatic parameters on different amounts of precipitation (low to very high amounts of precipitation) in different seasons was investigated for each of the stations using the quantile regression method. Then the results were analyzed. Results: The results of examining the changes trend of daily precipitation are showed that the high amounts of precipitation in the spring season in Bandar Abbas, Shiraz, and Torbat Heydarieh stations were reduced significantly, but very high amounts of precipitation (0.95 and 0.99 troughs) in the station Babolsar and Khorramabad have increased. Also, very high daily precipitation amounts in summer have decreased in Bandar Abbas station but increased in Torbat Heydarieh and Khorram Abad stations, significantly. While in the winter season, different amounts of precipitation in all seasons have a decreasing trend and there was only a significant positive slope in very high amounts of precipitation (slope of 0.99) in Babolsar station. In the investigation of the parameters affecting the extreme precipitation, the results showed that the amount of impact on the occurrence of heavy rainfall was relatively higher than low to median rainfall. The parameters of minimum temperature, minimum humidity, maximum humidity and wind speed have a positive effect and the maximum temperature parameter has a negative effect on heavy rainfall in different seasons and stations. The highest positive effect coefficients were in spring for wind speed in Babolsar (1.8), in summer for wind speed in Babolsar (3.8), minimum and maximum temperature in Bandar Abbas (-4.03 and 1.53), in Autumn season for maximum humidity and wind speed in Babolsar (2.57 and 2.99) and wind speed in Khorram Abad (1.54) and in winter, for wind speed in Babolsar and Bandar Abbas (1.94 and 6. 2), and minimum temperature in Torbat Heydarieh (0.96). Also, the highest negative effect coefficients of maximum temperature were in autumn and winter seasons (-0.88 and -0.72) in Babolsar and autumn season (-0.63) in Shiraz. Conclusion: The significant changes in increasing and decreasing precipitation are mostly related to the amounts of heavy precipitation, which are different in different seasons and climates. Also, the precipitation of the stations near the north and south coasts have been influenced by climatic parameters to a greater extent. In general, it can be said that flood precipitations are influenced by climatic parameters such as wind speed, humidity and temperature in order of importance and this effect is different depending on the location and time and the influence of different factors. Therefore, it is necessary to apply accurate planning for the correct use of received rainfall and optimal management in the target area using the results of such studies. Manuscript profile -
Open Access Article
19 - Comparison of performance of C-Vine and D-Vine tree copulas in multivariate analysis of precipitation characteristics
Maryam Shafaei Rasoul MirabbasiIn this study, the basic features of a tree vine copula such as the ability to decompose multivariate distributions into two-dimensional distributions, its flexibility in high-dimensional problems, and the use of conditional dependencies between variables have been cons MoreIn this study, the basic features of a tree vine copula such as the ability to decompose multivariate distributions into two-dimensional distributions, its flexibility in high-dimensional problems, and the use of conditional dependencies between variables have been considered. The purpose is to use C-Vine and D-Vine structures to determine the four-dimensional probabilistic distribution function of important characteristics of precipitation events of Cremona rain station located in Italy including maximum precipitation intensity total precipitation depth, wet period duration and dry period. So that, a combination of the most suitable Archimedean and elliptical copulas families was identified to fit the pair-copulas of each of the C-Vine and D-Vine structures. The optimal combined distribution functions of C-Vine and D-Vine structures were also calculated using chain density functions and compared with the four-dimensional experimental copula of important precipitation characteristics. Finally, the accuracy of C-Vine and D-Vine tree structures in determining the combined distribution functions of important precipitation characteristics was compared. The results showed that the RDLM C-Vine structure has a minimum value of evaluation criteria RMSE = 0.029 and MAE = 0.022, as well as a maximum of P-value = 0.35 and R2 = 0.998 among all C-Vine and D-Vine structures. As a result, it has the highest accuracy for frequency analyzing the of precipitation characteristics of Cremona station in Italy. Manuscript profile -
Open Access Article
20 - Evaluation of Global Gridded Precipitation Datasets for Drought Monitoring (Case Study: Great Karoon Watershed)
Behzad Navidi Nassaj Narges Zohrabi Alireza Nikbakht Shahbazi Hossein FathianIn this study, the Spatio-temporal performance of 5 global gridded precipitation datasets including GPCC V8, CHIRPS V2, ECMWF ERA5, NASA MERRA2, and PERSIANN-CDR (PCDR) in drought monitoring has been evaluated. For this purpose, the standardized precipitation index (SPI MoreIn this study, the Spatio-temporal performance of 5 global gridded precipitation datasets including GPCC V8, CHIRPS V2, ECMWF ERA5, NASA MERRA2, and PERSIANN-CDR (PCDR) in drought monitoring has been evaluated. For this purpose, the standardized precipitation index (SPI) and precipitation information of 13 synoptic stations of the Meteorological Organization of Iran during the thirty years of 1987-2016 has been used. Comparisons were carried out based on performance indices include correlation, mean square root error (RMSE), Nash-Sutcliffe efficiency coefficient, and modified agreement index (MAI) as well as drought detection accuracy metrics including False Alarm Ratio (FAR), probability of detection (POD) and the Critical Success Index (CSI). The results showed that GPCC, ERA5, PCDR datasets had a strong agreement with SPI observations so that they showed the drought trends and situations well and their R2 with observational SPI was Manuscript profile -
Open Access Article
21 - Fluctuations Analysis of Rainfall and Runoff in Aras Border Basin under Climate Change Conditions
Amin Sadeqi Yagob DinpashohIn this study, rainfall and runoff data recorded of selected stations of Aras Boundary Basin were used to analyze rainfall and runoff fluctuations and they are projected for horizons, 2050. The Pettitt test was used to detect the breakpoint in rainfall and runoff time s MoreIn this study, rainfall and runoff data recorded of selected stations of Aras Boundary Basin were used to analyze rainfall and runoff fluctuations and they are projected for horizons, 2050. The Pettitt test was used to detect the breakpoint in rainfall and runoff time series. Trends in rainfall and runoff were also calculated using the original and modified Mann-Kendall test. To project the future, general circulation models (GCMs) under two greenhouse gas emission scenarios i.e. RCP4.5 (low emission) and RCP8.5 (high emissions) were used. The Eureqa Formulize tool was used to simulate the rainfall-runoff process. Results showed that most of the abrupt changes have occurred in the second half of the 1990s. 83% of seasonal time series breakpoints were related to runoff. Also, 67% of the abrupt changes have occurred in the winter and spring seasons. The highest increase in annual rainfall (according to RCP4.5 scenario) at Nir station is expected to be 9% and the highest decrease in annual rainfall (according to RCP8.5 scenario) at Khoy station is predicted at 11%. It is also worth mentioning that in the seasonal time scale will have the highest rainfall reduction in summer. The Eureqa Formulize performed very well at all stations with NRMSE of less than 0.5%. The results indicated that the lowest slope of the base period runoff trend line (in seasonal time scale) was -1.3 million m3 in summer at Badalan station. There will be no significant change in the annual flow in the future period. Manuscript profile -
Open Access Article
22 - Projection of extreme precipitation in climate change condition and sensitivity analysis of results to downscaling method
Mohammad Reza Khazaei Reza KazemiThe frequency and intensity of extreme rainfalls will increase over many areas of the globe due to climate change. So, it is required to revise result of such studies based on the climate change scenarios. One of the most effective tools in such studies is Weather Gener MoreThe frequency and intensity of extreme rainfalls will increase over many areas of the globe due to climate change. So, it is required to revise result of such studies based on the climate change scenarios. One of the most effective tools in such studies is Weather Generators, including LARS-WG. While GCMs predict future changes in the various characteristics of precipitation, usually in downscaling using LARS-WG, just changes of monthly averages are considered. In this paper, the future climate change impact on extreme precipitation in Gorgan and Khoramabad stations are assessed; while, the results of two methods of applying just change in averages (simple method) or applying changes in various characteristics of precipitation (complete method) in downscaling are compared. For future, CanESM2 outputs under RCP2.6, RCP4.5, and RCP8.5 scenarios for 2036-2065 period were used. The results showed that for climate change impact assessment on extreme rainfalls, additional to change in averages, change in other precipitation characteristics should be considered. Because the results of the two methods are different. In Gorgan, for example, the annual maximum daily rainfall with a return period of 15 years in the future will increase by 16 to 21 percent according to the more complete method, but between 37 and 49 percent according to the simpler method. Based on the complete, Intensity of the extreme rainfalls at both stations will increase in the future. This increase will be between 23% and 30% for the 2-year return period and between 25% and 29% for the 30-year return period. Manuscript profile -
Open Access Article
23 - Application of the Nested Copula Functions for Analysis of Four variate of Meteorological Droughts (Case Study: West of Iran)
zabihollah khani temeliyeh Hossien Rezaie Rasoul MirabbasiDrought is a natural disaster and inevitable phenomenon, which should be considered preventable, but can be managed and organized. The main purpose of this study is to show how copula functions are used in the four-variable analysis of drought in the west of Iran. For t MoreDrought is a natural disaster and inevitable phenomenon, which should be considered preventable, but can be managed and organized. The main purpose of this study is to show how copula functions are used in the four-variable analysis of drought in the west of Iran. For this purpose, the drought characteristics, including severity, duration, inter arrival time and peak were extracted using modified Standardized Precipitation Index (SPImod). Then the frequency distributions were fitted to the mentioned drought characteristics and the best fitted marginal distribution were specified for every drought characteristics. The results showed that the gamma and exponential distributions had the best fitness on the drought severity and duration, respectively. Also, for drought peak and inter arrival time variables, the GEV function was known as the best fitted marginal distribution. In order to four variate analysis of drought characteristics, these variables were paired two by two using nested copula method. For this purpose, the fitness of nine copula functions, including Clayton, Ali-Mikhail- Haq, Farlie- Gamble- Morgenstern, Frank, Gamble, Gamble- Hougaard, Plackett, Philip Gamble and Joe were examined using Akaike Information Criterion (AIC), Maximum Likelihood (ML), and Nash-Sutcliffe Efficiency (NSE) criteria. The results showed that Joe copula is the best function for constructing the multivariate distribution in the study area. Also, this study showed that a four-variate analysis of drought provide useful information for planners and managers for drought prediction and planning to cope with drought consequences. Manuscript profile -
Open Access Article
24 - Drought Prediction Using North American Multi-Model Ensemble (NMME) Over Western Regions of Iran
Mehdi Moghasemi Narges Zohrabi Hossein Fathian Alireza Nikbakht Shahbazi Mohammadreza YeganegiBackground and Aim: Drought as a natural hazard significantly impacts various sectors such as agriculture and water resources and causes considerable damage to these sectors worldwide. Therefore, adaptation strategies should be taken to reduce drought damage, and in the MoreBackground and Aim: Drought as a natural hazard significantly impacts various sectors such as agriculture and water resources and causes considerable damage to these sectors worldwide. Therefore, adaptation strategies should be taken to reduce drought damage, and in the meantime, planning and adaptation to drought conditions using drought forecasting is one of the most effective strategies. Due to the need for drought forecasting and the limited studies that evaluated drought indicators obtained from the rainfall forecast output from the North American Multi-Model Ensemble (NMME) in Iran. This study evaluated these models in four catchments of Karkheh, Karun, Heleh, and Hindijan-Jarahi for1982-2018.Method: In this study, the monthly output of different NMME ensembles were evaluated in the forecast leads of 0 to 9 months from 1982 to 2018, the SPI drought index was calculated. Comparison of these data with GPCC data was used for evaluation. Three quantitative criteria, including correlation coefficient, RMSE, and BIAS, were used for evaluation. Also, to integrate the existing models, two methods: a: Arithmetic mean between the existing models and B: Weighted average between the models have been evaluated by considering the correlation coefficient (CC) results. Also, two criteria (i.e., POD and FAR) and the quantitative statistical criterion (i.e., correlation coefficient) were used to evaluate the SPI drought index.Results: The results of the precipitation evaluation of the models showed that the integrated models have better performance than the individual models. In this integrated model, the weighted model also had better performance. Evaluation of spatial distribution of precipitation models also showed the excellent performance of NMME models in Karun and Hindijan-Jarahi catchments in the zero-month forecast lead and Hindijan-Jarahi catchments in the one-month forecast lead. The results of drought index evaluation showed that integrated models, although having better performance in precipitation forecasting, but in drought forecasting, the best performance belongs to NASA-GMAO-062012 and CFSv2 models. The results also showed that drought index forecasts in three and six-month periods have better performance than one month. Spatial distribution evaluation also showed that the models perform better in the southern basins. In general, it can be concluded that NMME models have good performance in predicting drought in some places and specific forecast leads, so they should be evaluated at each point before use.Conclusion: The results of precipitation evaluation showed that, in general, integrating the output of dynamic models increases its proficiency, and integration in weighted mode (WeightedNMME) performs better than the non-weighted model (NMME). According to the zero-month forecast among individual models, the NASA-GMAO-062012 model has the most skills in terms of the correlation coefficient. However, in the one-month forecast lead in terms of the correlation coefficient, RMSE and BIAS, the best performance belongs to the CFSv2 model. Evaluation of drought indices showed that the model's performance could be different from their performance in predicting rainfall. WeightedNMME, for example, performed well in NASA-GMAO-062012 and CFSv2 months, although they performed well in predicting drought. The spatial evaluation also showed that the southern catchments perform better than other basins. Manuscript profile -
Open Access Article
25 - Uncertainty Evaluation due to TIGGE Global System Precipitation Data for Flood Forecasting
Soudabeh Behiyan Motlagh Afshin Honarbakhsh Asghar AzizianBackground and Aim: The occurrence of frequent floods in Iran necessitates a flood forecasting and warning system with a suitable lead time. The use of numerical rainfall forecasting models in flood forecasting and warning is one of the important measures taken by resea MoreBackground and Aim: The occurrence of frequent floods in Iran necessitates a flood forecasting and warning system with a suitable lead time. The use of numerical rainfall forecasting models in flood forecasting and warning is one of the important measures taken by researchers in most parts of the world. The TIGGE database includes mid-term precipitation forecasts simulated by global forecast centers. The purpose of this research is to evaluate the efficiency and the degree of uncertainty caused by the rainfall forecasts of four numerical models of the TIGGE database (including CPTEC, ECCC, ECMWF, and KMA) for simulating floods with the HEC-HMS hydrological model.Methods: In this research, the precipitation data of seven meteorological stations were used to evaluate the uncertainty of discharge from TIGGE database precipitation prediction models in the Poldokhtar watershed. Also, three flood events on March 24, 2017, April 6, 2018, and April 15, 2018, were studied. At first, precipitation forecasts were extracted from four centers CPTEC, ECCC, ECMWF, and KMA. Due to the existence of systematic error in the forecasts, a bias correction was done on them, and to correct the bias, the Delta method was used. Processed and raw forecasts of four rainfall forecasting models were entered into the HEC-HMS model for flood forecasting, and in the next step, the flow uncertainty assessment of the HEC-HMS model was performed in all members of the four rainfall forecasting models. In this research, 5 factors P, R, S, T, and RD were used for uncertainty analysis.Results: The results indicate the significant superiority of the ECMWF model in predicting precipitation events. The use of all 4 rainfall sources led to an acceptable simulation of the flood peak flow in three different events. Also, the predicted peak discharge time had little difference from the observed data. According to the results of the uncertainty analysis, the ECMWF model was considered the best model based on P, R, S, T, and RD factors. The KMA model performed well in severe and very severe floods. The group prediction system of TIGGE models also had an acceptable performance in all events. Also, the hydrological-meteorological prediction model predicted the time of flood occurrence and the probability of occurrence well.Conclusion: The intended research investigates flood forecasting and warning in the Poldokhtar watershed using the meteorological-hydrological system, based on meteorological forecasts of the TIGGE database and flood simulation using the HEC-HMS hydrological model. The final product of this system is probable discharge and flood forecast. The results reveal the success of the TIGGE database in flood forecasting. The ECMWF model excelled in predicting peak discharge. The upper and lower band calculation method was used to determine the uncertainty, which showed the uncertainty well. This system displayed the time of peak discharge well and with a small time delay, which indicates its good performance. The predicted rainfall from the four centers used in this study (ECMWF, ECCC, CPTEC, and KMA) have significant differences. To reduce these differences, we used a multi-model group forecasting system that had encouraging results. Manuscript profile -
Open Access Article
26 - Precipitation Trend Analysis in Zohre-Jirahi Basin in Kohgiluyeh and Boyer-Ahmad Province
Amirabbas Mahmoudian Bidgoli Mohammadsadegh Sadeghian Ali Saremi hooman HajikandiBackground and Aim: Water resources management has long been the focus of residents in Iran. Knowing of the time and the amount of rainfall contributes to better planning for water resources management, and this can be examined according to the available statistical dat MoreBackground and Aim: Water resources management has long been the focus of residents in Iran. Knowing of the time and the amount of rainfall contributes to better planning for water resources management, and this can be examined according to the available statistical data. The need for knowledge about precipitation trends in the study areas facilitates and legalizes water resources management and planning and helps to supply water with a higher reliability factor. The purpose of this research is to estimate and analyze the precipitation trends in Kohgiluyeh and Boyer-Ahmad Province within the Zohre-Jirahi basin.Method: This research is carried out in the Zohre-Jirahi basin in Kohgiluyeh and Boyer-Ahmad province based on the data from 1966 to 2018. In this regard, first, meteorological stations related to the studied area were located and their statistics were extracted from the received data. The stations’ data homogeneity is calculated based on the Kolmogorov-Smirnov method, and those without homogeneous data or with limited data are removed and, 30 stations are selected for data rebuilding. Rebuilding of missing data is done with Inverse Distance Weighted methods with the power of two and ordinary linear Kriging and after evaluating the methods by three criteria of Root Mean Square Error, Mean Absolute Error, and Coefficient of Determination, the optimal method is selected to rebuild the missing data in this study area. After rebuilding the data, a multi-dimensional raster containing rainfall information related to the years of the statistical period is produced and the time series of the relevant data is created in an array and per surface unit. In this research, according to the surface of the study area, time series of 8915 points are analyzed, and the trend of changes based on the Mann-Kendall method and Sen's slope on an annual and monthly scale are assessed in these points and, raster maps are produced.Results: Among the methods used for rebuilding missing data, based on the evaluation of the models, the optimal method for rebuilding missing data in the study area was the Inverse Distance Weighted method with a coefficient of determination of 0.95.The results of calculations on an annual scale show that the average Sen's slope in the study area does not have a significant trend and is equal to 0.0011. The average Sen's slope in the study area on a monthly scale is 0.28 in April and has an upward trend, in May Sen's slope is equal to -0.03 and indicates a downward trend and in June and July, an unobserved trend, and the results of Sen's slope calculations are zero. In August, there is an upward trend, and it’s value is equal to 0.11. In September, there is an upward trend, and it is equal to 0.06. In October, there is no observed trend, and it is equivalent to zero. In November and December, the trend is upward, and the average Sen's slope in the study area is equal to 0.19 and 0.62, respectively, and in January, February and March, the downward trend is equal to -0.48, -0.55, and -0.14.Conclusion: The results do not demonstrate a significant trend on an annual scale, however on a monthly scale, in December, April, November, August, and September, respectively, the highest upward trend is observed, while in February, December, March, and May, respectively, have the highest downward trend, and June, July, and October lack trends. The maximum average Sen's slope is calculated for December and equal to 0.62, and its minimum is in February and equal to -0.55. The management of water resources, especially in the agricultural sector as the main consumer, has large economic and social dimensions and is inevitable, and due to the great impact of water supply time to optimize and increase productivity, this research can be used to review the pattern and time of cultivation in this area. Groundwater artificial recharge, storage process, and consumption process should adapt to the new changes. Manuscript profile -
Open Access Article
27 - Determining the Monthly Wet and Dry Regimes Using Angot Precipitation Index in Ardabil Station
Roghayeh Asiabi-hir Raoof Mostafazadeh Saied NabaviBackground and Objective: Drought is the main causes of socioeconomic and environmental issues and the spatial and temporal variability of precipitation has a great influence on water resources availability. The Angot Precipitation Index (ratio between the average value MoreBackground and Objective: Drought is the main causes of socioeconomic and environmental issues and the spatial and temporal variability of precipitation has a great influence on water resources availability. The Angot Precipitation Index (ratio between the average values of multiannual of precipitation over wet and dry periods) is an indicator to determine the precipitation variations. The API highlights the climate significance of every month to detect dry or rainy regime.Material and Methodology: This study aims to assess and calculation of API in analysis of dry-wet periods of monthly precipitation in Ardabil station. The API values were calculated based on average daily values of precipitation in a year. Based on API values, dry and wet months were identified and the relationship between API and monthly precipitation characteristics according to Pearson correlation coefficient.Findings: According to the results, the value of API was 2.33 for the May month as a wet month and the November and April months are determined as normal precipitation regime (1.65 and 1.57 values, respectively) and other months have been classified into dry months as the API is less than the unity. Also, the API had a negative correlation with precipitation coefficient of variation (R2=0.408), and a positive correlation is exist between average monthly precipitation amounts and the API (R2=0.998).Discussion and Conclusion: The maximum API index value was observed in November and May months. The results indicated that the amount of Angot index was inversely correlated with coefficient of variations; while a direct relationship is exist with average monthly precipitations. Application of Angot index allows the determination of monthly precipitation regime on the basis of the vale ranges of the calculated index. Comparing the results of other drought indices in determining wet and dry months in climatic zones of Iran needs further investigations. Manuscript profile -
Open Access Article
28 - Potential Expected Climate Change Impact on Persian Gulf Coastal Mangrove Ecosystems Based on Temperature and Precipitation Variables
Hana Etemadi Hossein DelshabBackground and Objective: Climate change and global warming are one of the most widespread and important environmental hazards. The purpose of this study is to investigate the trend of minimum, maximum and rainfall temperatures in the past period of Bushehr as a coastal MoreBackground and Objective: Climate change and global warming are one of the most widespread and important environmental hazards. The purpose of this study is to investigate the trend of minimum, maximum and rainfall temperatures in the past period of Bushehr as a coastal province of the Persian Gulf and predict its climatic future by the end of 2100 AD, as well as the possible effects on the mangrove forest ecosystems of the Persian Gulf. Method: In this research, the statistical down scaling model (SDSM) along with two different GCMs entitle CanESM2 in three RCP2.6, RCP4.5 RCP8.5 scenarios and HadCM3 in A2 scenario, were used to simulate climatic variables during base (1961-2005), current and future (2010–2099) periods in Bushehr synoptic station. Furthermore, model evaluation and uncertainty assessment performed by five different statistical criteria and a non-parametric bootstrapping technique, respectively. Findings: The linear regression of the observed winter and summer mean temperature showed that mean temperature has increased +1.8 and +1.7°C over the past 47 years, respectively. Both, CanESM2 and HadCM3 model simulation results demonstrated that the most raise of minimum and maximum temperatures will occur in the future cold seasons. But, CanESM2 simulation analysis revealed that a decrease trend will occur in the minimum and maximum temperatures through future warm months. Also, HadCM3 simulation results showed that precipitation will rise in summer and fall seasons, while CanESM2 results presented an increase in rainfall variable throughout the year. Discussion and Conclusion: Both of models have predicted warmer winter in the next several decades. Based on CanESM2 model results that we will have longer warmer seasons, there is a possibility of prolonging reproduction (germination and flowering) season in Persian Gulf mangroves from 3 to 6 months. Based on our results, future rainfall is more likely to become more frequent and intense. If those precipitations do not occur in extreme events, accompany with high temperature can cause more mangrove expansion and growth in future decades. Manuscript profile -
Open Access Article
29 - Heavy metals concentrations (Ni / Pb / Cd) in Spinach (Spinacia oleraceae) with Effect of Atmospheric Desiccation (Case Study: Upper Hand and Downstream of Ramin Ahvaz Power Plant)
Ali Karimi Shooshtari Maryam Mohammadi RouzbahaniBackground and Objective: Several studies have been done to measure the concentration of heavy metals in vegetables, but so far, research on the determination of heavy metals in spinach and soil vegetation in upstream and downstream of the Ramin power plant using induct MoreBackground and Objective: Several studies have been done to measure the concentration of heavy metals in vegetables, but so far, research on the determination of heavy metals in spinach and soil vegetation in upstream and downstream of the Ramin power plant using inductively coupled plasma - Optical emission spectroscopy has not been performed. Therefore, the purpose of this study was to determine the concentration of cadmium, lead, and nickel in spinach and soil harvested from upstream and downstream fields of Ramin Power Plant.Material and Methodology: 99 vegetable and soil samples were collected. After chemical digestion (for soil using EPA 3050 and for plant using Jackson, 1980), preparation was performed by the ICP-OES induction plasma coupling device. Then, the results were analyzed using SPSS20 software.Findings: The results showed that concentrations of Cd, Pb and Ni in spinach and the soil bottom of the plant were 17.76, 20.89 and 43.68 mg / kg, 0.09, 0.1, 2.52 mg / kg, respectively. And in the spinach and the upper soil of the Ramin power plant were measured 6.81, 17.94 and 28.38 mg / kg, 0.88, 0.8 and 1.85 mg / kg respectively, which according to the standard limit. Concentration of cadmium, nickel and lead in spinach was higher and in soil below standard level. The concentration of all three metals in all vegetable samples was higher than the standard standard. The general pattern of concentrations of metals in vegetables and soil is Ni> Pb> Cd.Discussion and Conclusion: Considering the high concentration of heavy metals in spinach herb and the impact of atmospheric dry atmospheric precipitation in the region, focusing on the potential risk of heavy metals contamination for food safety and human health in agricultural soils and upstream and downstream Ramin power plants it is very necessary. Manuscript profile -
Open Access Article
30 - Comparison of magnetic properties and adsorption capability of synthesized magnetic Graphene oxide Nano-composite via co-precipitation and solvo-thermal methods
Fatemeh Einollahipeer Nader Bahramifar Habibollah UnesiBackground and Objective: Nano-sorbents are suitable for pollutants removing from aqueous environment. Therefore, the aim of this study was to compare magnetization of magnetic graphene oxide nano-composite by using co-precipitation and solvothermal methods. In addition MoreBackground and Objective: Nano-sorbents are suitable for pollutants removing from aqueous environment. Therefore, the aim of this study was to compare magnetization of magnetic graphene oxide nano-composite by using co-precipitation and solvothermal methods. In addition, the capability of nano-adsorbent was conducted in order to examine removal efficiency of Cd (II) from aqueous solution. Method: Graphene oxide (GO) was synthesized by modified Hummers method and magnetized using co-precipitation and solvothermal procedures. The amine functionalization of as-prepared magnetic graphene oxide was performed by reflux method in the presence of ethylenediamine as functional group and cold synthesis method in the presence of dichloromethane as reaction solvent. The synthesized adsorbents were used for Cd (II) removal from aqueous solutions and the effects of pH, amount of adsorbent, contact time, initial concentration of Cd (II) ions and temperature were investigated. Findings: According to FTIR, XRD and VSM analyses, the synthesized magnetic graphene oxide with co-precipitation showed higher magnetization values than that of from the solvothermal method. The adsorption results displayed that the synthesized adsorbent with solvothermal and reflux processes of amination has the highest adsorption capacity of 207 mg.g-1. But it is only 82 mg.g-1 with co-precipitation and cold amination process. Kinetic data showed better correlation with pseudo-second-order equation and the Freundlich model was found to fit for the isotherm data. Discussion and Conclusion: The magnetization values of adsorbent in co-precipitation method was better while the adsorption capacity reduced. The loss of adsorption capacity was due to high loading of magnetic particles under surface of GO, which leads to block the carboxyl functional groups. This was also confirmed by elemental analysis. The amount of nitrogen was lower in co-precipitation process comparing to solvothermal method. In batch adsorption, the adsorption process was found to be endothermic and spontaneous in nature. The results suggest that the solvothermal and reflux procedures was more efficient in amine functionalization and adsorption process. Manuscript profile -
Open Access Article
31 - Study on Application of Electrocoagulation Process to Remove Heavy Metals Lead, Cadmium and Chromium from Water
Farzad Hashemzadeh Seyd Mehdi BorgheiBackground and Objective: The increasing use of heavy metals for industrial purposes has caused an increment in discharge of these contaminants as industrial wastewater into the environment. Electrocoagulation is a complicated process with several functional mechanisms MoreBackground and Objective: The increasing use of heavy metals for industrial purposes has caused an increment in discharge of these contaminants as industrial wastewater into the environment. Electrocoagulation is a complicated process with several functional mechanisms to remove pollutants. Use of this process as an effective and efficient method to remove heavy metals from water has been recommended.Method: In this research studied parameters are: reaction time, distance between electrodes, initial heavy metal concentration, electrode material, and inlet voltage and pH value. Then, the effect that any of these parameters was investigated. In order to do that a 5.4-liter pilot from plexiglass with length of 20 cm, width of 15 cm and height of 18 cm with electrodes of iron, aluminum and steel having length and width of 15 cm and thickness of 0.2 cm and voltage between 0 to 48 v and a direct current (DC) power supply was used.Findings: removal efficiency by electrocoagulation is directly related to voltage and reaction time increment, so that the best removal efficiency was occurred in voltage of 40 v and reaction time of 40 min. By increasing the initial concentration of metals from 1 to 50 mg/l, removal percentage of lead, cadmium and chromium was decreased. Most amounts of removal percentage were gained using iron– aluminum electrodes in a condition in which the distance between them was 5 cm and pH value was equal to 3.Discussion and Conclusion: Due to the excellent efficiency of the electrocoagulation process in removing heavy metals of chromium, lead and cadmium, the feasibility of removing the metals desired by this process is evaluated and can be used as a novel solution in removing metal ions from industrial effluents. Manuscript profile -
Open Access Article
32 - Study on Heavy Metals Content (Fe, Pb and Cd) in Atmospheric Precipitation Collected from the High Traffic Intensity Regions of City of Hamedan
Bahare Baharmastian soheil Sobhanardakani saeed Jameh BozorgiBackground and Objective: Air pollution is one of the most important environmental problems which can lead to the human health effects especially in the metropolitans. ­ Atmospheric precipitation including rain and snow are the most effective way for removing pollut MoreBackground and Objective: Air pollution is one of the most important environmental problems which can lead to the human health effects especially in the metropolitans. ­ Atmospheric precipitation including rain and snow are the most effective way for removing pollutant from the atmosphere and its heavy metals can describe the variability of the environmental pollution in different urban areas. Therefore, this study was conducted to assess the metal (Fe, Pb and Cd) concentrations in the atmospheric precipitation collected from high traffic intensity areas of city of Hamedan in 2014. Method: A total of 24 snow samples were collected from 8 selected stations located in different regions of city of Hamedan with high traffic intensity. The samples were stored in polyethylene bottles and were acidified at a pH lower than 2 by adding concentrated HNO3 in order to avoid metal adsorption onto the inner bottle walls. Element (Fe, Pb and Cd) concentrations were determined using ICP-OES. All statistical analyses were done by SPSS software. Findings: The results showed that the mean concentrations (µg/L) of Fe, Pb and Cd in snow samples were 69.5 ± 143, 10.2 ± 8.94 and 17.6 ± 0.290, respectively. Also, the mean concentrations of Cd were significantly higher than maximum permissible limits established by WHO. Conclusion: The results indicate that rainfall collected from the high traffic intensity regions of city of Hamedan is polluted with Cd due to the high traffic volumes and their emitted pollutions, therefore, for maintaining of surface and groundwater resources and also public health consider the suitable strategies is recommended. Manuscript profile -
Open Access Article
33 - Zoning of the degree of risk in the southern areas of Khuzestan province in the conditions Climate change with emphasis on industrial infrastructure
Arash Rahimi Reza Borna jafar Morshedi Jebreel GhorbanianBackground and Objective: climate change can be considered one of the biggest environmental challenges of the recent era, which indicates unusual changes in the internal climate of the earth's atmosphere and its consequences in different parts of the globe, which is a s MoreBackground and Objective: climate change can be considered one of the biggest environmental challenges of the recent era, which indicates unusual changes in the internal climate of the earth's atmosphere and its consequences in different parts of the globe, which is a serious threat to the environment. The purpose of this research is to prepare a vulnerability zoning map of infrastructures in the southern regions of Khuzestan in the conditions of climate change. Material and Methodology: for this purpose, using previous sources and interviews with experts, eleven variables of total annual precipitation, average temperature of hot and cold season, the trend of maximum precipitation of more than 5 mm per day, the number of dust codes, the occurrence of heat waves above the 95th percentile, precipitation changes, displacement of coastline, underground water changes, floods and inundation and temperature changes during 2019 to 2019 were investigated. By using two trend analysis tests, i.e. Sence slope estimator trend analysis test and Mann-Kendall trend analysis test, the trend of the 32-year time series of these elements during the basic statistical period (1985-2017) was investigated. Findings: The southern parts of the studied region of Khuzestan had an average temperature of more than 38 degrees Celsius per year, while the northern and central parts of the studied region had a temperature of more than 38.5 degrees Celsius per year.The southern part of Khuzestan has an annual rainfall equivalent to more than 273 mm per year, while the southern parts of the studied area have less than 200 mm of rainfall per year and in some cases about 156 mm per year. Discussion and Conclusion: The results show that high and very high risk areas cover 80% of the region. Manuscript profile -
Open Access Article
34 - The study of relation between aerosols and quality of rain water over Tehran during 2012-2013 years
Dina Abdemanafi Amir-Hussain Meshkatee Sohrab Hajjam Majid VazifedoustBackground and Objective: Precipitation is one of the most efficient mechanisms for washing the atmospheric pollutants, specifically particulate ones out.The study chemistry of rain water was shown pollutions in atmosphere. Method: Accordingly, to do that 16 rain MoreBackground and Objective: Precipitation is one of the most efficient mechanisms for washing the atmospheric pollutants, specifically particulate ones out.The study chemistry of rain water was shown pollutions in atmosphere. Method: Accordingly, to do that 16 rainwater samples from two Mehrabad and Aghdasieh synoptic stations collected during the autumn and winter of 2012 and spring of 2013 (the city rainy seasons). Concentrations of major inorganic ions () and pH in bulk precipitation samples collected in the Tehran city of I.R. of Iran were analyzed. In this article, Enrichment Factors, Correlation Analysis and Principal Component Analysis had been used in order to identify the sources of ions found in sampled rain waters. Findings: Results show that concentrations of the found substances were higher over the Mehrabad station. The mean concentration of ions indicated that,, and were the main anions, while ,, were the main cations. anion had important role in acidity of the rain water. The Bicarbonate anion had the highest concentration, among all other ions, over both stations and plays an important role in reduction of the acidity of the rain water. Study upon the potential sources of the ions over Tehran by means of Correlation Analysis, Enrichment Factor and Principle Component Analysis indicate that existence of Qom salt lake and desert in the south of the city were the main source of the and. There are anthropogenic sources for. The other ions were from anthropogenic and dust origin. Discussion and Conclusion: The pollutants in rainwater over Tehran were derived from long range and local (industry and traffic) sources. Manuscript profile -
Open Access Article
35 - Analyzing and Monitoring the Meteorological Droughts in the Region of Sistan and Balouchestan
Hamid Zare Abianeh Aliakbar Sabziparvar Safar Marofi Fereshte Ghiyami Sayede Shaghayegh Mirmasoud Azade KazemiIn this research, analyzing the meteorological drought is performed by using of five commonly usedindices including: Rainfall Standard Index (ZI), Deviation from Mean Index (SDI), Percent of NormalPrecipitation Index (PNPI), Rainfall Anomaly Index (RAI) and Precipitatio MoreIn this research, analyzing the meteorological drought is performed by using of five commonly usedindices including: Rainfall Standard Index (ZI), Deviation from Mean Index (SDI), Percent of NormalPrecipitation Index (PNPI), Rainfall Anomaly Index (RAI) and Precipitation Classification range (PC)on seasonal and yearly precipitation data in the four synoptic stations of Zahedan, Zabol, Chabaharand Iranshahr, using the same period starting from 1964 and ending to 2005. The result showed thatSDI method performs more reliable estimation compared with PNPI, ZI, RAI methods in the annualand seasonal time scales. Based on SDI method, Sistan and Balouchestan Province has experiencedfrequent meteorological drought in both seasonal and annual time scales. In annual time scale, thefrequency (percent) of intense and severe droughts was smaller than frequency of mild and mediumdroughts. In the seasonal time scale, on average, based on SDI method, most (42%) of severe andintense droughts occurred in summer, but in winter, the risk of severe and intense droughts wassmaller (12%), We also used 3-year and 5-year moving averages method for evaluation of trends anddrought duration in the annually time scale in the mentioned sites. The results showed that the rainfallstandard index (RAI) performs different results from other indices. Other results also indicate that theintensity and frequency of meteorological drought are increasing in this province Manuscript profile -
Open Access Article
36 - The case study of impacts of Tehran ambient air pollution on the cloud and precipitation characteristics
Dina Abdemanafi Sohrab Hajjam Amir-Hussain Meshkatee Majid VazifedoustBackground and Objective: Concentration and type of atmospheric aerosols are among of the most important factors affecting the macro and micro structure of clouds and their precipitation. Method: In this article, the case study has been carried out to investigate the r MoreBackground and Objective: Concentration and type of atmospheric aerosols are among of the most important factors affecting the macro and micro structure of clouds and their precipitation. Method: In this article, the case study has been carried out to investigate the relationship between atmospheric air pollution, microphysics of cloud and their precipitation over Tehran city. The case study in this paper (2012/12/06) was performed before the the rainfall that increased AQI index for particulate matter which made Tehran to be closed for two days. This event was compared with two similar rainfalls shortly before or after it and it was found out that in the two similar rainfalls the AQI index had been healthy during the days before precipitation. Ion concentrations in the rainwater were measured by ion-chromatography and microphysics of clouds were studied by MODIS on board Aqua and Terra satellite. Findings: The results showed that ions concentration, especially anthropogenic ions (nitrate, nitrite, chloride and fluoride), in rainwater samples in polluted air was higher than in clear air. Also particulate pollution reduced the effective radius droplet of the mixed-phase clouds before the rain, and increased the cloud optical thickness, cloud water path and cloud top pressure and temperature during the precipitation. Discussion and Conclusion: The ions in rain water and the cloud microphysics characteristics related to the concentration of aerosols in the atmosphere. Also, local particle pollutions changed regional microphysics of cloud Manuscript profile -
Open Access Article
37 - Evaluation of Corrosion and precipitation potential in Ghaemshahr, s Village Drinking Water
Maryam Khademian Ghadekolai Mostafa zamani Fateme Ghafari Mohamadreza rahimi Samaneh mahmoodporCorrosion and precipitation are the most important factors in the quality control of drinking water networks play an important role in the transmission system and distribution of water in transmission system and the distribution of water in terms of health and economic MoreCorrosion and precipitation are the most important factors in the quality control of drinking water networks play an important role in the transmission system and distribution of water in transmission system and the distribution of water in terms of health and economic aspects can play.The aim of this study was to determine the potential for corrosion and perecipitation of drinking water used in Ghaemshahr villages, that was done in 2015. Physical and chemical quality samples and the potential for corrosion and precipitation were determined by Langlier, Rayzner, Puckorious, Aggressiveness, and Larsson. Results indicate that mean and standard variation for Langlier index is 0.052 and 0.43, for Rayzer index is 6.99 and 0.78 for aggressiveness index is 5.85 and 0.81 for Larsson indexrespectivity is 0.47 and 0.24. According to these finding it was concluded that drinking water of Ghaemshahr villages was mild precipitation. Manuscript profile -
Open Access Article
38 - Magnetic Properties of Cobalt Ferrite synthesized by Hydrothermal and Co-precipitation Methods: A Comparative Study
Saeed Abedini Khorrami Qazale Sadr Manuchehri -
Open Access Article
39 - A Novel Method for the Synthesis of CaO Nanoparticle for the Decomposition of Sulfurous Pollutant
Meysam Sadeghi Mir Hassan Husseini -
Open Access Article
40 - Synthesis and Surfactant Effect on Structural Analysis of Nickel Doped Cobalt Ferrite Nanoparticles by C-precipitation Method
Pirouz Derakhshi Roshanak Lotfi -
Open Access Article
41 - Evaluation of the Effective Parameters on Fe3+ Precipitation in the Bioleaching Process
Monireh Zolfaghari Abbas Rashidi Ali Haghighi Asl -
Open Access Article
42 - Synthesis of B4C - Nano TiB2 Composite Nano Powder by the Chemical Precipitation Method
M. Saeedi Heydari H. R. Baharvandi -
Open Access Article
43 - Assessment of clouds seeding project in increasing of water harvesting in the Fars province using remote sensing and geographic information system techniques
Mahboubeh Olumi Majumerd Mohammad Zare Samaneh PourmohammadiDrought and climate change phenomena have severe negative impacts on natural vegetation and agricultural section in Central Iran during the last decades. Cloud seeding is one of the efficient methods to reduce the effects of climate change. The purpose of this study was MoreDrought and climate change phenomena have severe negative impacts on natural vegetation and agricultural section in Central Iran during the last decades. Cloud seeding is one of the efficient methods to reduce the effects of climate change. The purpose of this study was to investigate the effect of clouds seeding on rainfall in Fars province. November, December, February and April months in the water year of 2010-2009, selected as the prone month of precipitation in Iran, were evaluated cloud seeding projects in Fars province. Historical regression was used to evaluate the cloud seeding project. In the first step, raster monthly precipitation maps for each month of year in the period was 34 years (1977-2010) were plotted using the Kriging method to measure rainfall amounts of each year. Then, the volume of precipitation in April, February, January, and November in the target area stations were calculated and used as a dependent variable. Next, precipitation time series for each month of the period of 1977-2010 in the control area stations were calculated and entered into the regression as independent variables. Correlation between the volume of rainfall in both regions (target and control) were analyzed. Then, expected rainfall in the region was estimated and its confidence was determined using statistical methods. Comparing expected and actual rainfall, percentage of changes in precipitation due to clouds seeding in Fars province were determined. Results showed an increase of about 15% in precipitation in Fars province during the four months of the water year of 2009-2010. Manuscript profile -
Open Access Article
44 - An agro-climatic zoning of wheat cultivation in the Kermanshah province
Rastegar Mohamadi Javad Khoshhal Dstjerdi Daryoush Rahimi Razieh NouriSince the most cultivated areas allocated to dry land wheat in Kermanshah province, therefore the climatic zoning wheat cultivation seemed necessary for this province. To reach the research objectives was used the climatic data 6 synoptic stations (1989-2012) and climat MoreSince the most cultivated areas allocated to dry land wheat in Kermanshah province, therefore the climatic zoning wheat cultivation seemed necessary for this province. To reach the research objectives was used the climatic data 6 synoptic stations (1989-2012) and climate data 8 climatological stations (2008-2013). Initially for analyzing and performance steps, used software SMADA for different distribution possibilities, selected planting date and the best statistical distribution Then extracted map precipitation, temperature and thermal stresses and applied contribution of each layer in the layer zoning, So that the highest percentage of participation is related to precipitation The germination period With 31.5% and the lowest percentage of participation is related to heat stress (30) degrees Step reaching With 8.1%. The results showed that Between Elements of climate, precipitation and temperature There are important factors of wheat cultivation in the end By combining layers To the Method Weighted overlap in ArcGIS environment, were extracted wheat climatic zoning map. The results showed that the very appropriate areas with an area of 16.7% in parts of the northwest, west and southwest, appropriate areas with an area of 14.36% in the northwest, west and southwest, the average areas with 15.27% in the southwest, west, central, north, northeast and southeast and poor areas with 53.64%, is located more in central and northeast. This research can be used in order to the more prominently capability of geographical information systems in the composition and production of spatial and attribute data, and help managers and decision makers to access information and provide appropriate model according to the type of crop planning. Manuscript profile -
Open Access Article
45 - Monitoring and prediction land use/ land cover changes and its relation to drought (Case study: sub-basin Parsel B2, Zayandeh Rood watershed)
Shahin Mohammadi Khalil Habashi Saeed PormanafiLand use and land cover (LULC) change because of its impact on natural ecosystems has become a concern for natural resources protectors and managers. The present study aimed to predict LULC changes and also to study the relation of drought with these changes in the sub- MoreLand use and land cover (LULC) change because of its impact on natural ecosystems has become a concern for natural resources protectors and managers. The present study aimed to predict LULC changes and also to study the relation of drought with these changes in the sub-basin Parsel B2 with an area of 21100 hectares using CA-Markov model and Standard Precipitation Index (SPI). For this purpose, using the preprocessed images of the sensors TM, ETM+, and OLI for the years 1986, 2001 and 2016, respectively, the LULC map was provided with supervised classification and maximum likelihood method. To validate the CA-Markov model, the LULC maps have been predicting for 2016 and they were compared to the reference land use map of 2016. After ensuring the accuracy of the predicted results for the year 2016, the related land use and land cover maps were predicted for the year 2030. The result showed a relation between LULC changes and drought condition. Based on result predicted for the year 2030, rain-fed agriculture 6.95% increase and range land 6.66% decrease in area. Thus In the event of drought and abandonment rain-fed agriculture land, soil erosion, increasing and also grazing pressure on the remaining range land causing range land degradation. Therefore, if the current land use strategy with current management remain, land degradation in the region will be inevitable. Manuscript profile -
Open Access Article
46 - Surveying of the past, present, and future of vegetation changes in the central Alborz ranges in relation to climate change
Diana Askarizadeh Hosein Arzani Mohammad Jafary Javad Bazrafshan Iain colin PrenticeAcceleration of climate trend change is caused by the swift shift of rangeland conditions that using modern methods of evaluation to them are counted to sustainable management of the rangelands. In order for an investigation of trend change of rangeland vegetation due t MoreAcceleration of climate trend change is caused by the swift shift of rangeland conditions that using modern methods of evaluation to them are counted to sustainable management of the rangelands. In order for an investigation of trend change of rangeland vegetation due to climate change, central Alborz rangelands were selected. Normalized Difference Vegetation Index (NDVI) for the period of 30-year (1987-2016) was extracted by Landsat satellite, TM, ETM+, and OLI series. Drought periods were determined using the Standardized Precipitation Index (SPI). The Markov Chain model was used to anticipate the future changes of rangeland vegetation. The results showed that the vegetation cover index’s changes have risen and fallen for three decades in which, despite of increasing for some years 1986 (0.86), 2002 (0.87), 2005 (0.87), and 2015 (0.86); the changes trend was decreasingly for 1995 (0.53), 1998 (0.65), 2000 (0.62), and 2008 (0.61) years, especially for fair to very poor classes. The highest correlation (91.5%) between the SPI and NDVI was shown that severe to moderate drought has taken place along with decreased vegetation periods. Moreover, the Markov Chain model has anticipated a forcible declined change of vegetation cover for 2031 and 2046 periods. Therefore, range management approaches have to prepare itself in order to the gradual increase of temperature, which has destructive effects on vegetation cover, via regulating of grazing capacity and replacing of highly performance livestock in the future. Manuscript profile -
Open Access Article
47 - Downscaling TRMM satellite-based precipitation data using non-stationary relationships between precipitation and land surface characteristics
Bahareh Zanjani Hesam Seyed Kaboli Mohsen RashidianSatellite-based precipitation dataset has been widely used to estimate precipitation, especially over regions with sparse rain gauge networks. However, the low spatial resolution of these datasets has limited their application in localized regions and watersheds. So, ha MoreSatellite-based precipitation dataset has been widely used to estimate precipitation, especially over regions with sparse rain gauge networks. However, the low spatial resolution of these datasets has limited their application in localized regions and watersheds. So, having an accurate estimation of precipitation by satellites along with the adequate spatial scale in hydrologic studies is the main goal of this study. In this research, Geographically weighted regression (GWR) method was investigated to downscale the Tropical Rainfall Measuring Mission (TRMM-3B42 Version 7) over the DEZ river basin in the southwest of IRAN for 2010-2011. Downscaling was performed based on the non-stationary relationships between the TRMM precipitation and the Digital elevation model (DEM) derived products, the Normalized difference vegetation index (NDVI), the Enhanced vegetation index (EVI) and the Land surface temperature (LST). The result shows that the downscale precipitation at 1 km spatial scale had significantly improved spatial resolution, and agreed well with data from the rain gauge stations. For the 16-day precipitation, Mean square root means square error (RMSE) and absolute mean error (MAE) values are 22.7 mm and 7.45 mm, respectively. However, the accuracy of the model varies in a different location and depends on the vegetation condition. Manuscript profile -
Open Access Article
48 - Evaluation of indices based on remote sensing in drought monitoring of Neyriz city
Mohammad ShabaniBackground and Objective Knowing the extent and severity of drought in a region and planning to reduce its effects is one of the most important principles of management in regional planning to combat drought. Drought monitoring and management in an area using remote sen MoreBackground and Objective Knowing the extent and severity of drought in a region and planning to reduce its effects is one of the most important principles of management in regional planning to combat drought. Drought monitoring and management in an area using remote sensing data and satellite imagery as a suitable tool in temporal and spatial monitoring of agricultural drought has always been the focus of regional managers. The purpose of this study is to investigate the efficiency of remote sensing data and satellite images in the zoning of agricultural drought in the years 2000 to 2021 in Neyriz city. For this purpose, three vegetation condition index (VCI), temperature condition index (TCI), and vegetation health index (VHI) were extracted from MODIS satellite images for the desired time period. The results of these indices were compared with the values of the standard precipitation index (SPI) in time series of 1, 3, 6, 9, 12, 18, 24, and 48 months.Materials and Methods The study area in this study is Neyriz city located in the southeast of Fars province with an area of 10787 Km2 and is part of one of the watersheds of Bakhtegan Lake. The average altitude of the region is 1798 meters, the maximum altitude of the region is 3235 meters and the minimum altitude is 1476 meters above sea level. The average annual rainfall, temperature, and evapotranspiration of the basin are 204.8 mm, 19 °C, and 1058.3 mm, respectively. In this study, the rainfall data of Neyriz synoptic station during the statistical period of 22 years (2000-2021) were used to calculate the SPI index in time series of 1, 3, 6, 9, 12, 18, 24, and 48 months. Then, 3 indices based on satellite imagery including vegetation condition (VCI), temperature condition index (TCI), and plant health index (VHI) were extracted from Modis measured data for May month from 2008 to 2021 and with standard precipitation index (SPI) were compared in time series of 1, 3, 6, 9, 12, 18, 24 and 48 months based on the correlation coefficient. Finally, the most appropriate drought index based on satellite images was selected from the indices and the percentage of drought classes was determined based on the selected index in the study area.Results and Discussion The results of calculating the values of the SPI index using DIP software in time series of 1, 3, 6, 9, 12, 18, 24, and 48 months in the statistical period of 2000-2021 showed that the trend of curves in some years is decreasing, in some years it has been increasing and in most years it has been almost normal. On average, the incidence of droughts and wetlands according to the SPI index in different time series during the statistical period is 68% in normal conditions, 18% in wet conditions, and 16% in drought conditions. The results of calculating the SPI index in different ground series were analyzed based on data from synoptic stations and remote sensing data. For this purpose, the values obtained from all indices based on satellite images including VCI, TCI, and VHI are extracted and compared and their correlation coefficient with the ground SPI index in time series 1, 3, 6, 9, 12, 18, 24, and 48 became. VCI index values in 2000 have the lowest value (32.1%) and in 2020 have the highest value (41.3%) during May. Therefore, based on the value of the VCI index during the statistical period in 2008, severe drought conditions prevailed in the region, and in 2020, more favorable vegetation and wetting conditions prevailed in the region. The results obtained from the SPI index in different time series also confirm the fact that the most severe drought and wet season during the statistical period studied in the two years 2000 and 2020, respectively, in the region. In addition, the VCI index is most correlated with the SPI index in different series and the SPI relationship is significant with the all-time series. TCI index has no significant correlation with any of the time series and has a weak correlation with the SPI index in different time series. In addition, the VHI index has a significant correlation with time series of one, three, six, and twelve months only at the level of 5% and its correlation with the SPI index in different time series is much less than the VCI index. Spatial distribution of drought intensity based on the values of the studied indices in May 2008 showed that the eastern parts of the region, which is also located at low altitudes, have been more affected by drought. The study of the area affected by drought classes based on the TCI index in 2008 showed that there is no very severe drought in the study area, 11% of the area suffers from moderate drought, 22% of the area suffers from mild drought and 67% has no drought. According to the VCI index, the level of severe drought on the date is 0.14%, severe at 0.33%, moderate at 17%, mild at 77%, and no drought at 6%. Also, according to the VHI index, there is no severe or severe drought in the study area only 9% of the area suffers from moderate drought and 91% does not have a drought. Spatial distribution of drought severity based on the values of the studied indices in May 2020 shows that in the study area according to the TCI index there is no very severe drought on the target date and 5% of the area has moderate drought, 22% drought Mild and 73% lack drought. According to the VCI index on the target date, the percentage of drought is very severe 0.5%, severe 0.8%, moderate 5%, mild 31%, and no drought 62%. Also, according to the VHI index in May 1999, 0.2% of the area has a moderate drought, 30% has a mild drought and 69% has no drought. According to this index, there is no very severe drought in the region.Conclusion Drought is one of the most important natural disasters that affect millions of people and large parts of the world every year. This phenomenon, which starts slowly and has a creeping nature, can cause a lot of damage to agriculture, natural resources, and the environment. Knowing how to occur and preparing drought severity maps based on new methods has a very positive and serious impact on drought management in an area. One of the new and widely used methods in temporal and spatial monitoring of drought is the use of drought indices based on satellite images, which has recently been used in drought-related topics. The results of the SPI index analysis showed that in most time series, the most severe drought and wet season during the study period occurred in 2000 and 2020, respectively. The results also showed that the temperature condition index (TCI) has no significant correlation with any of the time series and has a weak correlation with the SPI index in different time series. The plant health index (VHI) with time series of one, three, six, and twelve months has a significant correlation at the level of 5% and its correlation with the SPI index in different time series is less than the vegetation condition index (VCI). The value of the VCI index in 2008 had the lowest value (32.1%) and in 2020 had the highest value (41.3%) during May, which is consistent with the results obtained from the SPI index in the region. A comparison of the results of this study with the results of other researchers shows the excellent accuracy of remote sensing indices in drought monitoring. Therefore, the use of remote sensing technology in drought monitoring in areas that do not have meteorological stations or have meteorological stations with low density or scattered is recommended. Manuscript profile -
Open Access Article
49 - Drought prediction and modeling by hybrid wavelet method and neural network algorithms
Jahanbakhsh Mohammadi Alireza Vafaeinezhad Saeed Behzadi Hossein Aghamohammadi Amirhooman HemmasiBackground and Objective A drought crisis is a dry period of climate that can occur anywhere globally and with any climate. Although this crisis starts slowly, it can have a serious impact on health, agricultural products, the economy, energy, and the environment for a MoreBackground and Objective A drought crisis is a dry period of climate that can occur anywhere globally and with any climate. Although this crisis starts slowly, it can have a serious impact on health, agricultural products, the economy, energy, and the environment for a long time to come. Drought severely threatens human livelihood and health and increases the risk of various diseases. Therefore, modeling and predicting drought is one of the most important and serious issues in the scientific community. In the past, mathematical and statistical models such as simple regression, Auto-regression (AR), moving average (MA), and ARIMA were used to model the drought. In recent years, machine learning methods and computational intelligence to model and predict drought have been of great interest to scientists. Computational intelligence algorithms that have been previously considered by scientists to model drought include multilayer perceptron neural network, RBF neural network, support vector machine, fuzzy, and ANFIS methods. In this research, the purpose of modeling and predicting drought is by using three neural network algorithms, including multilayer perceptron, RBF neural network, and generalized regression neural. The drought index used in this research is the standardized precipitation index (SPI). In this research, the wavelet technique in combination with artificial neural network algorithms for modeling and predicting drought in 10 synoptic stations in Iran (Abadan, Babolsar, Bandar Abbas, Kerman, Mashhad, Rasht, Saqez, Tehran, Tabriz, and Zahedan) have been used in different climates and with suitable spatial distribution throughout Iran.Materials and Methods This study, initially using monthly precipitation data between 1961 and 2017, SPI drought index in time scales of 3, 6, 12, 18, 24, and 48 months through programming in soft environment MATLAB software implemented. The results of this step were validated using the available scientific software MDM and Drinc. Then, prediction models were designed using the Markov chain. In this study, a total of six computational intelligence models, including three single models of multilayer perceptron neural network (MLP), radial basis function neural network (RBF), and generalized regression neural network (GRNN), and three hybrids wavelet models with these three models (WMLP-WRBF-WGRNN) have been used to model and predict the SPI index in 10 stations of this research. In implementing all these six models, the MATLAB software programming environment has been used. In this study, four types of discrete wavelets were used, including Daubechies, Symlets, Coiflets, and Biorthogonal. Due to the better performance of the Dobbies wavelet, this type of wavelet was used as a final option in the research. In the Daubechies wavelet used between levels 1 to 45, level 3 showed the best performance among different SPI time scales; therefore, the Daubechies level 3 wavelet was used in all hybrid models of this study. After training all six algorithms used, the evaluation criteria of coefficient of determination (R2) and root mean square error (RMSE) was used to measure the difference between actual and estimated values.Results and Discussion The results of this study showed that computational intelligence methods have high accuracy in modeling and predicting the SPI drought index. In the first stage, the results showed that the individual MLP, RBF, and GRNN models, if properly trained, have close results in modeling and predicting the SPI drought index. In the next step, it was observed that the wavelet technique would improve the modeling results. In using the wavelet technique in combination with three single models MLP, RBF, and GRNN, the choice of wavelet type is also more effective in modeling, so in this research, the first of the four types of discrete wavelets Daubechies, Symlet, Qoiflet, and Biorthogonal in combination with Three single models of this research were used and the results of these four types of wavelets showed the relative superiority of the Daubechies wavelet over the other three wavelets. In using the Daubechies wavelet, since this wavelet has 45 times and the choice of order was also effective in modeling, it was observed by testing the wavelet 45 times that the 3rd wavelet, in general, has higher accuracy in all time scales of SPI index, 3, 6, 12, 18, 24 and 48 months and also in all three algorithms MLP, RBF, and GRNN. Therefore, in this research, the third-order Daubechies wavelet was used in all three algorithms of this research, as well as in all time scales. The results showed that combining the wavelet technique with all three models MLP, RBF, and GRNN will improve the results. The research graphs showed that for the quarterly time scale, the values obtained from the single model prediction in MLP and RBF modeling have a somewhat one-month phase difference compared to the hybrid model, while in the GRNN model, this prediction difference is negligible. The modeling results for both single and hybrid modeling modes indicate that there is no phase difference between the single and hybrid modeling methods in time scales of 6, 12, 18, 24, and 48. For the 12- and 24-month time scales, the single GRNN model had more fluctuations and errors in SPI monthly modeling and forecasting, while the hybrid model in these two-time scales had much better behavior in monthly modeling and forecasting. Distribution diagrams of data related to observational SPI of Abadan station showed that the modeling results for single and hybrid modes in 3 and 6-month time scales are less accurate than other time scales and fit line separation, and its uncertainty is higher than others. However, in all neural network models and in all time scales, the hybrid method has shown more accuracy. The numerical results of the study indicate that in all SPIs and stations under study, the differential values of R2 are positive, which indicates higher values of R2 in the hybrid model than in single neural network modeling, which indicates an improvement in hybrid modeling compared to individual models. Also, the differential values of RMSE are negative in all studied models and stations, which indicates that the amount of RMSE in predicting hybrid models is lower than individual neural network models. In the research graphs, it can be seen that the amount of differences in RMSE and R2 indicates a greater difference in time scales 3 and 6 than the time scales 12, 18, 24, and 48, which somehow goes back to the nature of the data of these time scales. The most significant improvement in R2 and RMSE is from the 3-month low to the 48-month high, respectively.Conclusion From the findings of this study, it can be concluded that artificial neural network algorithms are efficient methods for modeling and predicting the SPI drought index. The use of wavelets in all three models of artificial neural networks will also improve the results. It can also be concluded that for better modeling of the SPI drought index, it is necessary to select the optimal wavelet type and order. From the results of this study, it can be concluded that the wavelet technique has a greater impact on the lower time scales, i.e., 3 and 6 months, than the higher scales, i.e., 24 and 48 months. Manuscript profile -
Open Access Article
50 - Evaluation of rainfall on a daily, monthly and annual basis using satellite imagery (Case study: west boundary basin of Iran)
Ghazaleh Madadi Saeid Hamzeh Ali Akbar NorooziPrecipitation variable is the key parameter of agricultural and hydrometeorology studies. Therefore, measurement and estimation of rainfall at the regional level help to understand the manner of water and energy cycles. In spite of the high variability of te MorePrecipitation variable is the key parameter of agricultural and hydrometeorology studies. Therefore, measurement and estimation of rainfall at the regional level help to understand the manner of water and energy cycles. In spite of the high variability of temporal and spatial precipitation quantity, precipitation monitoring using ground stations at regional scales is considerably difficult. The use of satellite images with high spatial resolution is therefore recommended. However, it is first necessary to evaluate temporal and spatial accuracy of data. The aim of this study was to evaluate the accuracy of Tropical Rainfall Measuring Mission (TRMM) satellite data for estimating daily, monthly, and annual rainfall on a regular spatial scale (0.25° ×0.25°) during 2000-2012, and to compare these estimated data with precipitation data at 30 stations (synoptic and climatological) in the west boundary basin of Iran. The Pearson correlation coefficient was calculated daily, monthly, and annually for the mentioned rainfall period changes. The results indicated a significant correlation (p<0.05) among the monthly and annual collected data of terrestrial and satellite precipitation. The relationship between monthly precipitation data from satellite images and observed data from stations were also determined using a linear and nonlinear regression for each year. The model reliability was also subsequently determined using statistical validation. Manuscript profile -
Open Access Article
51 - ارزیابی مدلهای CMIP5 جهت شبیه سازی بارش با استفاده از ترکیب دادههای بارش شبکهای APHRODIT و بارش ماهواره ای PERSIANN-CDR در سراسر استان خوزستان
کاظم رنگزن علی شهبازی زهرا جریده مصطفی کابلی زادهیکی از مهم ترین محدودیت های مدل های گردش عمومی جو، بزرگ مقیاس بودن متغیرهای اقلیمی شبیه سازی شده می باشد. بنابراین می بایست به روش های مختلف ریزمقیاس شوند تا توانایی لازم جهت برازش به منطقه مورد مطالعه را داشته باشند. انتخاب مدل GCM مناسب ب Moreیکی از مهم ترین محدودیت های مدل های گردش عمومی جو، بزرگ مقیاس بودن متغیرهای اقلیمی شبیه سازی شده می باشد. بنابراین می بایست به روش های مختلف ریزمقیاس شوند تا توانایی لازم جهت برازش به منطقه مورد مطالعه را داشته باشند. انتخاب مدل GCM مناسب برای محدوده مورد مطالعه نقش بسیار مهمی در شبیه سازی پارامتر موردنظر (بارش) برای آینده دارد. در این تحقیق از مدل های CMIP5 شامل BCC-CSM1.1.M، MPI-ESM-MR و MPI-ESM-LR به منظورارزیابی مدل ها در دوره پایه و مشخص کردن بهترین مدل جهت برازش به منطقه مورد مطالعه استفاده شد. بدین ترتیب که ابتدا هیستوریکال مدل و دیتای شاهد (ترکیب بارش ماهواره ای پرژین و بارش شبکه ای آفرودیت) به دو دوره تقسیم شد دوره اول 1992-1983 به عنوان دوره پایه و دوره دوم 2003-1994 به عنوان دوره ارزیابی. شاخص های راست آزمایی میانگین خطای مطلق و شاخص امتیاز مهارتی میانگین خطای مطلق بین مدل ها و شاهد در دوره ارزیابی قبل و بعد از اصلاح و ریزمقیاس نمایی به صورت فصلی در نرم افزار متلب برای تمامی پیکسل های استان خوزستان محاسبه شد. .نتایج حاکی از آن است که قبل از اعمال روش ریزمقیاس نمایی عامل تغییر (دلتا) مدل BCC-CSM1.1.Mدارای خطای کمتر نسبت به دو مدل دیگر بود و دو مدل دیگر از لحاظ میزان خطا تقریبا مشابه بودند. .بعد از اعمال روش دلتا مدل BCC-CSM1.1.M بهترین بهبود را از خود نشان داد و مدل های MPI-ESM-MR, MPI-ESM-LR به ترتیب در رتبه های دوم و سوم اهمیت قرار گرفتند. بنابراین بیشترین اعتماد بعد از ریزمقیاس نمایی به روش دلتا برای آینده تحت سناریوی RCP5.4 برای استان خوزستان به مدل BCC-CSM1.1.M اختصاص یافت. Manuscript profile -
Open Access Article
52 - برآورد بارش رواناب و تهیه نقشههای کاربری اراضی و سطوح کشاورزی با استفاده از فن آوری سنجش از دور در حوضه آبریز رود زرد در استان خوزستان
رحیم آورند حسن ترابی پوده امروزه فن آوری سنجش از دور، در تمام زمینههای علمی و اطلاع رسانی در دنیا مورد استفاده است و نتایج بسیار رضایت بخشی داده است. در این تحقیق با بکار گیری فن آوری سنجش از دور و استفاده از تصاویر ماهواره ای، ضریب شماره منحنی با دقت بالایی برآورد شد ودبی پی More امروزه فن آوری سنجش از دور، در تمام زمینههای علمی و اطلاع رسانی در دنیا مورد استفاده است و نتایج بسیار رضایت بخشی داده است. در این تحقیق با بکار گیری فن آوری سنجش از دور و استفاده از تصاویر ماهواره ای، ضریب شماره منحنی با دقت بالایی برآورد شد ودبی پیک سیلاب، با دقت خوبی محاسبه گردید.در این مطالعه از جهت تاثیر تغییرات کاربری اراضی روی دادههای یک واقعه تاریخی، برای تصمیم گیری و ارزیابی تغییرات دوره بلند مدت کاربری اراضی حوضه نیز استفاده شده است. اندازه گیریهای بارش و جریان روزانه هم زمان، نشان داد که تغییرات کاربری اراضی، بر روی رابطه بارش- رواناب، در حوضه رودخانه مذکور تاثیر دارد. ولی به دلیل اینکه تصاویر ماهواره ای (به غیر از دو دوره 1990 و 2002 ) در دورههای زمانی مختلف، موجود نبود، نتایج ارزیابی تغییرات کاربری اراضی و تاثیر آن بر نتایج رابطه بارش- رواناب، نشان داده نشده است. در این مطالعه سیمای کلی حوضه، از سال 1990 تا 2002 تغییرات محسوسی نداشته است. نتایج، نشان داد که سنجش از دور و تکنولوژی GIS، برای تجزیه و تحلیل توزیع عمق رواناب، زیر حوضههای مورد مطالعه، مناسب می باشد. این فن آوری برای پیش بینی رواناب در آبخیزداری و منابع آب، می تواند مورد استفاده قرار گیرد. Manuscript profile -
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53 - استفاده از روشهای شبکه عصبی موجکی و سیستم استنتاج فازی عصبی تطبیقی در پیشبینی بارش ماهانه
اباذر سلگی حیدر زارعی بهداد فلامرزیپیش بینی بارش به دلیل ماهیت تصادفی آن در مکان و زمان همواره با مشکلات بسیاری مواجه بوده است و این عدم قطعیت از اعتبار بسیاری از مدل های پیش بینی می کاهد. امروزه شبکه های غیرخطی به عنوان یکی از سیستم های هوشمند در پیش بینی یک چنین پدیده های پیچیده ای بسیار مورد استفاده ق Moreپیش بینی بارش به دلیل ماهیت تصادفی آن در مکان و زمان همواره با مشکلات بسیاری مواجه بوده است و این عدم قطعیت از اعتبار بسیاری از مدل های پیش بینی می کاهد. امروزه شبکه های غیرخطی به عنوان یکی از سیستم های هوشمند در پیش بینی یک چنین پدیده های پیچیده ای بسیار مورد استفاده قرار می گیرند. یکی از روش هایی که در سال های اخیر در زمینه هیدرولوژی مورد توجه قرار گرفته است، استفاده از تبدیل موجک به عنوان روشی نوین و مؤثر در زمینه آنالیز سیگنال ها و سری های زمانی است. در پژوهش حاضر، تجزیه و تحلیل موجک به صورت ترکیب با شبکه عصبی مصنوعی و مقایسه با سیستم استنتاج فازی- عصبی تطبیقی برای پیش بینی بارش ایستگاه وراینه در شهرستان نهاوند انجام شد. برای این منظور، سری زمانی اصلی با استفاده از تئوری موجک به چندین زیرسیگنال زمانی تجزیه شد، پس از آن این زیرسیگنال ها به عنوان داده های ورودی به شبکه عصبی مصنوعی برای پیش بینی بارش ماهانه استفاده شد. نتایج به دست آمده نشان داد که مدل ترکیبی موجک- شبکه عصبی عملکرد بهتری نسبت به مدل سیستم استنتاج فازی- عصبی تطبیقی دارد و می تواند برای پیش بینی بارش کوتاه مدت و بلند مدت استفاده شود. همچنین نتایج نشان داد که مدل ترکیبی موجک- شبکه عصبی در برآورد نقاط حدی به خوبی عمل می کند. Manuscript profile -
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54 - بررسی تاثیر تغییراقلیم بر بارشهای حداکثر و حداکثر سیلاب محتمل رودخانه کارون
زهرا رامک جهانگیر پرهمت ابراهیم فتاحی مهران زند حسین صدقیتغییر اقلیم یکی از مهم ترین چالش هایی است که بخش های مختلف زندگی انسان را در روی زمین تحت تاثیر قرار داده است و یکی از آثار آن، تاثیر بر وقایع حدی (سیلاب و خشکسالی) می باشد. امروزه یکی از مهم ترین موضوعات مورد بحث این است که در آینده شدت بارش های سنگین و سیلاب ها نسبت ب Moreتغییر اقلیم یکی از مهم ترین چالش هایی است که بخش های مختلف زندگی انسان را در روی زمین تحت تاثیر قرار داده است و یکی از آثار آن، تاثیر بر وقایع حدی (سیلاب و خشکسالی) می باشد. امروزه یکی از مهم ترین موضوعات مورد بحث این است که در آینده شدت بارش های سنگین و سیلاب ها نسبت به دوره کنونی چگونه تغییر خواهد کرد. در این تحقیق تلاش شده است تا تاثیر این پدیده بر بارش های حدی و حداکثر سیلاب محتمل (PMF) رودخانه کارون در محل پل شالو مورد بررسی قرار گیرد. برای اینکار، دما و بارش دوره آتی (2039-2011) با استفاده از مدل HadCM3 و بر اساس سناریوهای انتشار A1B، A2 و B1 و مدل ریزمقیاس نمایی آماری LARS-WG شبیه سازی شده است. در گام بعدی حداکثر بارش محتمل حوضه به روش سینوپتیکی برآورد و پس از آن، با استفاده از مدل بارش- رواناب HEC-HMS و مدل ذوب برف SRM، حداکثر سیلاب محتمل این حوضه برآورد و در نهایت تاثیر تغییر اقلیم بر بارش های حداکثر و نیز حداکثر سیلاب محتمل این حوضه بررسی شده است. نتایج حاصل از این تحقیق نشان می دهد که حداکثر بارش محتمل حوضه در دوره 2039-2011 نسبت به دوره کنونی تحت سناریوی A1B، با 5 درصد کاهش و تحت سناریوهای A2 و B1 به ترتیب با 5 درصد و 10 درصد افزایش روبه رو خواهند شد. همچنین پیش بینی می شود سهم سیلاب ناشی از ذوب برف در مطالعات PMF، تحت سه سناریوی ذکر شده به ترتیب 24/1 ، 58/1 و 23/1 برابر افزایش داشته باشد. به همین ترتیب حداکثر سیلاب محتمل (PMF) این حوضه در تداوم های مختلف تحت سناریوی A1B کاهش و تحت سناریوی A2 و B1 افزایش خواهد داشت و شدت تغییرات تحت سناریوی B1 شدیدتر خواهد بود. Manuscript profile -
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55 - مطالعه مناسبترین روش برآورد بارش مؤثر جهت تعیین نیاز آبی گندم دیم در اصفهان
شمیم لاریجانی محمد سالاریان حسین بانژاد معصومه نجفیمحاسبه مقدار بارش مؤثر به‎عنوان یکی از منابع تأمین آب مورد نیاز برای کشت گندم از اقدامات مطالعاتی زیربنایی به شمار میرود که میتواند در برنامهریزیهای مربوطه مورد استفاده قرار گیرد. لذا شناسایی و به‎کارگیری روشی مناسب برای برآورد بارش مؤثر به‎خصوص در کشت د Moreمحاسبه مقدار بارش مؤثر به‎عنوان یکی از منابع تأمین آب مورد نیاز برای کشت گندم از اقدامات مطالعاتی زیربنایی به شمار میرود که میتواند در برنامهریزیهای مربوطه مورد استفاده قرار گیرد. لذا شناسایی و به‎کارگیری روشی مناسب برای برآورد بارش مؤثر به‎خصوص در کشت دیم اهمیت دوچندان پیدا میکند. در این پژوهش به ارزیابی روشهای مختلف تعیین بارش مؤثر ازجمله: روشهای سرویس حفاظت خاک اداره کشاورزی ایالات متحده (SCS)، بارش قابل اطمینان، تجربی، روش وزارت کشاورزی ایالات متحده (USDA)، درصدی و رنفرو، به کمک نرمافزار SPSS و با آزمون آماری دانکن در شهرستان اصفهان و برای کشت گندم دیم، پرداخته شده است. نتایج حاصل از این ارزیابی نشان داد که روش رنفرو به‎دلیل آنکه مقادیر بارش مؤثر را بیش‎تر از خود بارش نشان میدهد مورد پذیرش واقع نشده است. روشهای SCS و بارش قابل اطمینان و تجربی، به دلیل بدست آمدن مقادیر زیاد منفی (صفر)، بیش‎تر مناسب مناطق مرطوب میباشند. نتایج نشان داد که روش درصدی و USDA تطابق بیش‎تری با میزان بارش نسبت به سایر روشها دارند. باتوجه به تطابق بیش‎تر با مقدار بارش متوسط ماهانه بهترین روش برای محاسبه بارش موثر در اصفهان و برای گندم روشUSDA پیشنهاد گردید. Manuscript profile -
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56 - بررسی روند تغییرات زمانی و خصوصیات مکانی بارش و خشک سالی هواشناسی، در غرب کشور طی چند دهه اخیر
صفر معروفی حسین طبری علی آئینی حسین معروفیخشک سالی یکی از جدی­ترین مشکلات جوامع بشری و اکوسیستم­ها، در نتیجه تغییرپذیری اقلیمی است. این پدیده، سالانه موجب میلیاردها دلار خسارت در سطح جهان می­گردد و نسبت به دیگر بلایای طبیعی، مردم بیشتری را تحت تأثیر قرار می­دهد. در این تحقیق، روند تغییرات سری&sh Moreخشک سالی یکی از جدی­ترین مشکلات جوامع بشری و اکوسیستم­ها، در نتیجه تغییرپذیری اقلیمی است. این پدیده، سالانه موجب میلیاردها دلار خسارت در سطح جهان می­گردد و نسبت به دیگر بلایای طبیعی، مردم بیشتری را تحت تأثیر قرار می­دهد. در این تحقیق، روند تغییرات سری­های زمانی بارندگی و خشک سالی هواشناسی در ده ایستگاه واقع در غرب کشور، در دوره آماری 1384-1355 مورد بررسی قرار گرفته است. مقادیر شدت خشک سالی با استفاده از شاخص بارش استاندارد (SPI)، در مقیاس زمانی 12 ماهه محاسبه گردید. همچنین تحلیل روند داده­ها با استفاده از آزمون من-کندال و تخمین گر سِن انجام شده است. نتایج این تحقیق نشان داد که داده­های بارندگی و شدت خشک سالی، دارای تغییرات زیادی نسبت به میانگین در دوره مورد مطالعه بوده­اند. این تغییرات با افزایش خشکی به سمت شرق منطقه مورد مطالعه، فزونی یافته است. نتایج آزمون­ها نشان داد که سری­های زمانی بارندگی، دارای روند معنی­دار کاهشیمعنی­دار در ایستگاه­های سرپل ذهاب، بیجار، سنندج و سقز به ترتیب به میزان 99/7، 68/6، 51/5 و 03/5 میلی­متر در هر سال بوده است. همچنین شدت خشک سالی در ایستگاه­های کرمانشاه، سقز، سنندج و خرم­آباد در چهار دهه گذشته روند معنی­دار افزایشی داشته است. نتایج بدست آمده نشان داد که تمامی ایستگاه­های مطالعاتی، حداقل یک خشک سالی بسیار شدید را در دوره مورد مطالعه تجربه نموده­اند. Manuscript profile -
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57 - بررسی روند تغییرات دما و بارش ایستگاههای هواشناسی استان خوزستان
سعید پاکدل نرگس ظهرابیپدیده تغییر اقلیم یکی از مسائل حیاتی برای بشر امروزی محسوب میشود و خشکسالی نیز به عنوان یک ناهنجاری اقلیمی با علائم کمبود بارش و منابع آب در دسترس، در گستره وسیعی در طول زمان اتفاق میافتد. از میان متغیرهای اقلیمی، دما و بارش مهمترین متغیرهایی هستند که تغییرات آنها بطو Moreپدیده تغییر اقلیم یکی از مسائل حیاتی برای بشر امروزی محسوب میشود و خشکسالی نیز به عنوان یک ناهنجاری اقلیمی با علائم کمبود بارش و منابع آب در دسترس، در گستره وسیعی در طول زمان اتفاق میافتد. از میان متغیرهای اقلیمی، دما و بارش مهمترین متغیرهایی هستند که تغییرات آنها بطور مستقیم در رطوبت خاک و جریانهای سطحی و زیرزمینی منعکس میشود. در مطالعه حاضر پس از گردآوری داده های ماهانه بارش و دما در دوره آماری 2012-1983 و بررسی کیفیت و همگنی و صحت سنجی آنها، با استفاده از آزمون ناپارامتری من – کندال به بررسی روند تغییرات دما و بارش در ایستگاه های منتخب هواشناسی استان خوزستان پرداخته شد. نتایج دوره آماری مطالعه شده نشان دهنده افزایش روند تغییرات دمایی سالانه در کلیه ایستگاه­های منتخب استان است که با توجه به نتایج بدست آمده متوسط دمای سالانه به ترتیب در ایستگاه­های رامهرمز، بستان و آبادان با 8/7 ، 5/7 و 7 درجه سانتی­گراد در دوره مطالعاتی 2012-1983، بیشترین روند افزایشی را نشان می­دهند. به همین ترتیب ایستگاه مسجدسلیمان کمترین شیب افزایشی را با افزایش دمای سالانه ی 2/4 درجه سانتی­گراد را در دوره ی سی ساله بصورت افزایشی نشان می­دهد. براساس نتایج ، متوسط بارش سالانه، روند کاهشی این متغیر را در اکثر ایستگاهها نشان میدهد. اما متغیر بارش برخلاف دما، تغییرات یکنواختی نشان نمیدهد. در این مطالعه ایستگاههای بندر ماهشهر و امیدیه که در حدود بخش جنوب شرقی استان قرار دارند، افزایش نسبی بارش را در دورهی 30 ساله 2012-1983 نشان داده است. Manuscript profile -
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58 - ارزیابی و مقایسه بارش ماهانه محصولات ERA-Interim،PERSIANN-CDR،PERSIANN-CCS و CRU در استان خوزستان
رضا کوچکی علی شهبازی خیرالله خادمیکمبود و توزیع نامناسب ایستگاههای بارانسنجی یکی از چالشهای پژوهشگران علوم هیدرولوژی و آب وهوا شناسی است. در این پژوهش قابلیت بهکارگیری چهار محصول بارش شبکهبندی شده PERSIANN-CDR، PERSIANN-CCS،ERA-Interimو CRU بهعنوان مکمل یا جایگزین دادههای زمینی در مقیاس ماهانه Moreکمبود و توزیع نامناسب ایستگاههای بارانسنجی یکی از چالشهای پژوهشگران علوم هیدرولوژی و آب وهوا شناسی است. در این پژوهش قابلیت بهکارگیری چهار محصول بارش شبکهبندی شده PERSIANN-CDR، PERSIANN-CCS،ERA-Interimو CRU بهعنوان مکمل یا جایگزین دادههای زمینی در مقیاس ماهانه مورد ارزیابی قرار گرفت. این ارزیابی از طریق مقایسه با دادههای مشاهداتی و روشهای آماری صورت پذیرفت. بهمنظور بررسی توانایی برآورد بارش این چهار محصول از آمارههای ضریب همبستگی پیرسون (CORR)، اریبی (BIAS)، قدر مطلق خطا (MAE)، مجذور میانگین مربعات خطا (RMSE)، مجذور میانگین مربعات خطای نرمال شده (NRMSE)و ضریب کارایی مدل (EF)استفاده شد. این نمایههای آماری بهصورت پهنهای و در قالب نقشه برای سطح استان استخراج شد. مشاهده شدPERSIANN-CCSدر سطح استان در تخمین بارش ناموفق بود و از قابلیت اطمینان ضعیفی برخوردار میباشددرحالیکه محصولات ERA-Interim،PERSIANN-CDRو CRUهمخوانی مناسبی با دادههای مشاهداتی دارند و روند بارش ماهانه با خطای کمی برآوردمیکنند. در برخی نقاط استان بارش PERSIANN-CDR از قابلیت اطمینان بسیار بالایی برخوردار بود اما درمجموع کمترین دامنه خطا و بیشترین قابلیت اعتماد از بین 3 محصول ماهوارهای یادشده برای بارش ERA-Interimبه دست آمد و در صورت نقصان و نبود منابع دادهای زمینی میتواندبهعنوان یک منبع دادهای جایگزین و کمکی بکار گرفته شود. Manuscript profile -
Open Access Article
59 - Prediction of the changes in some climate variables in Darehrood River of Aras Basin over next decades using of GCM Models
Ebrahim Fataei Ali i Aziz Seiied Taghi Seiied Safaviyan Ali Akbar Imani Akram Ojaghi Habib FarhadiClimate change is one of the natural features of atmospheric circulation anomalies and fluctuations in the meteorological parameters such as rainfall and temperature can be achieved. These anomalies in most of the world led to impair in natural ecosystems. Studies show MoreClimate change is one of the natural features of atmospheric circulation anomalies and fluctuations in the meteorological parameters such as rainfall and temperature can be achieved. These anomalies in most of the world led to impair in natural ecosystems. Studies show that emissions of greenhouse gases in recent decades have increased considerably. These gases increase in the atmosphere, causing changes in Earth's climate parameters. With widely varying meteorological simulation models of generators weather in recent decades, it is essential that these changes in a series of simulated apply. In this study, using statistical downscaling techniques, GCM models under the greenhouse gas emission scenarios (A1B, A2, B1) for the period 2039-2011 using statistical models LARSE-WG daily data of temperature, precipitation and radiation small scale, and the results were evaluated on synoptic stations. The results show that changes in climate parameters will be created during the study period. So that the average temperature between the stations under study between 31.0 to 69.3 ° C will increase and rainfall will increase to 2.8 to 21.5 percent Manuscript profile -
Open Access Article
60 - The Effect of Brainstorming Method on Reducing Reading Learning Disorder in Elementary School Students of Hamedan City
elaheh zahedi no Azam ghavidelThe present study was conducted with the aim of investigating the effect of brainstorming teaching method on reducing reading learning disorder in elementary school students of Hamadan city. The present study was a cross-sectional study in terms of practical purpose, a MoreThe present study was conducted with the aim of investigating the effect of brainstorming teaching method on reducing reading learning disorder in elementary school students of Hamadan city. The present study was a cross-sectional study in terms of practical purpose, a cross-sectional study in terms of time, a quantitative data type, and a semi-experimental one in terms of research method, with a pre-test-post-test design with a control group. The statistical population of the study consisted of all the students with learning disabilities of the reading type, in the primary level, who had referred to the learning disabilities center in Hamedan city in the academic year of 2001-2001. From the aforementioned statistical population, 30 people were selected by available sampling method and were randomly divided into two experimental and control groups, then the experimental group underwent 8 training sessions (two sessions in one week) for 45 minutes. brainstorming training, but the intervention was not implemented for the control group. Then, both groups were given a post-test using the mentioned questionnaire. The research tools include the brainstorming program based on Le Francois (1991) brainstorming protocol and Shirazi and Nilipour's reading disorder test (2013), in order to analyze the data and examine research hypotheses from multivariate and univariate covariance analysis. used. The results showed that the effects of brainstorming teaching on reading comprehension are significant and the effects of brainstorming teaching do not affect reading speed and reading accuracy. The brainstorming teaching method could not create a significant difference between the experimental and control groups in the components of reading speed and correctness of the material. Manuscript profile -
Open Access Article
61 - Examining Snow Cover Changes in Relation to Drought Using Remote Sensing Techniques and GIS (Case Study of the West and East Azerbaijan Provinces)
Fahimeh Hooshmand mohammadebrahim afifiIn this research, to determine the changes in the level of snow cover in relation to drought, satellite data has been used in order to determine the snow cover and meteorological station data has been applied to estimate the drought. In this regard, at the first stage, MoreIn this research, to determine the changes in the level of snow cover in relation to drought, satellite data has been used in order to determine the snow cover and meteorological station data has been applied to estimate the drought. In this regard, at the first stage, satellite data was collected from NASA's Web site from 1385 to 1395, and after geometric and atmospheric corrections based on the NDSI index and using of bands 4 and 6, was applied to determine the level of snow cover and drought rate has been estimated based on SPI index. Studies of snow cover reveal that the level of snow cover has been reduced and this is proportional to the drought rate, and the prevailing trend in the level of snow cover and SPI is a downward trend. However, in spite of the prolonged and increased SPI index, the level of snow cover has been reduced or vice versa. The reason for this can be investigated through the type of precipitation during these years and it is possible that most type of the precipitation, during the years in which snow cover has been less, has been rainy type and in the drought years with increased snow cover, type of downfall has been more snowy. Manuscript profile -
Open Access Article
62 - Effect of Heat Treatment on Structural and Magnetic Properties of Nanocrystalline SrFe12O19 Hexaferrite synthesized by Co-Precipitation Method
Mansoureh Ganjali Monireh Ganjali Arvin Eskandari Masoud Aminzare -
Open Access Article
63 - Chemical synthesis and characterization of Zn-doped cadmium oxide based nanoparticles: As nanofluids for thermophysical applications
M Sheela Pauline W A Samson Nesaraj -
Open Access Article
64 - Drought effects on surface water quality in Golestan province for Irrigation Purposes, Case study: Gorganroud River
Nader Jandaghi Ali Heshmatpour Mojtaba Ghareh Mahmoodlu Saeedeh PasandIn this study, a part of the Gorganroud basin was selected to evaluate of the drought effect on 13 water physicochemical parameters. After collecting meteorological and hydrometric stations data in a period of 43-year (1350-1393), a 5-year drought index was determined u MoreIn this study, a part of the Gorganroud basin was selected to evaluate of the drought effect on 13 water physicochemical parameters. After collecting meteorological and hydrometric stations data in a period of 43-year (1350-1393), a 5-year drought index was determined using the standard precipitation index and moving average method. Then, the water quality parameters were obtained for a long-term and a drought period using the available hydrometric stations data. The average concentration of most of anions and cations, electrical conductivity, and sodium adsorption ratio have increased from upstream to downstream, so that, this increase in the downstream station is about seven times higher than its upstream station in the drought period. The average of anions, cations, electrical conductivity, and sodium absorption ratios were increase during the drought period compared to the long-term period. Using the Wilcox diagram, agricultural water quality is decreases in the direction of river flow, so that the water category changes from C2S1 (suitable for agriculture) in the upstream to C4S3 (harmful to agriculture) in the downstream. Therefore, it can be concluded that the occurrence of drought periods has a significant effect on the water quality factors in comparison with the long-term period, so that, the agricultural water quality drastically has reduced by a decrease in rainfall and subsequently decrease in river discharge within the drought period. Manuscript profile -
Open Access Article
65 - Zoning of agricultural climate of corn crop in lorestan
gholamreza ahmadi parviz kardovani hossein mohammadiThis study analyzes the climatic-agricultural zoning of rain-fed corn in Lorestan province and its role in reducing environmental risks. The study method in this research is citation-descriptive in which the information (precipitation, temperature, etc.) of a 20-year st MoreThis study analyzes the climatic-agricultural zoning of rain-fed corn in Lorestan province and its role in reducing environmental risks. The study method in this research is citation-descriptive in which the information (precipitation, temperature, etc.) of a 20-year statistical period (1377-1397) has been gathered on a daily, monthly, seasonal and annual basis from 53 synoptic stations, climatology and rain gauge, inside and outside of this province. Then, considering the required conditions for this crop such as heat thresholds, growth period and the amount of water requirement, suitable growth zones has been determined by GIS and after that the zoning of agricultural climate of corn crop in this province has been mapped. On the base of the final obtained map, this province has 8588.15 kilometers of potential lands, 13938.13 square kilometers of semi-potential lands and 5631.57 square kilometers of non-potential lands. Kriging interpolation method has been used to create coordination in data integration and also auxiliary points to find the regions with the same amount of temperature and rainfall. Manuscript profile -
Open Access Article
66 - Downscaling of satellite-based precipitation considering the spatially heterogeneous relationship between precipitation and environmental variables
Arman Abdollahipour Hassan Ahmadi Babak AminnejadThe satellite-based precipitation products are one of the sources of rainfall estimation. Nonetheless, for usage in the local regions and, or for parameterizing of meteorological and hydrological models at basin scales, their spatial resolution is often coarse. Therefor MoreThe satellite-based precipitation products are one of the sources of rainfall estimation. Nonetheless, for usage in the local regions and, or for parameterizing of meteorological and hydrological models at basin scales, their spatial resolution is often coarse. Therefore, in this study, a downscaling– calibration method was developed for global precipitation measurement (GPM) satellite estimates (at 0.1° spatial resolution), for one year from 01/04/2014 to 31/03/2015, by considering the spatial heterogeneity of the relationship between precipitation and the environmental variables using the mixed geographically weighted regression (MGWR) model for Golestan province. In obtaining improved precipitation data with 1 km spatial resolution at an annual scale, the results showed that (1) the proposed method not only improved the spatial resolution of precipitation but also increased accuracy; (2) the downscaled and calibrated precipitation data (CC = 0.74, bias = 0.23) performed better than the original data (CC = 0.58, bias = 0.35) against ground observations. Manuscript profile -
Open Access Article
67 - Seasonal monitoring of drought in the country Using CRU network data
Azadeh ArbabyDrought is a natural and recurring feature of the climate that occurs in all climatic regions, but its structure and important effects vary from region to region.The main purpose of this study is to investigate the country's meteorological droughts over a long period of MoreDrought is a natural and recurring feature of the climate that occurs in all climatic regions, but its structure and important effects vary from region to region.The main purpose of this study is to investigate the country's meteorological droughts over a long period of time using network data with appropriate spatial and temporal resolution. Data analysis was performed using SPEI multivariate index. The results of drought calculation showed that in terms of time during the period (1966-2015) the rainfall of the cold period of the year decreases in general, the decrease in rainfall in different parts of the country mainly starts from the late 90s In the last years of the study period, except in autumn, we see more repetition of dry periods and unlike the late 80s, droughts have occurred more. Moderate drought intensities are significant and experience of severe droughts, which are among the most critical areas of the country. Manuscript profile -
Open Access Article
68 - Fractal analysis of daily rainfall in Karkheh and Dez catchment
ziba hasanvand Dariush Yarahmadi hasan lashkari Hamid MirhashemiPrecipitation is important climatic varibles which is directly involved the hydrological cycle. Iran is considered the most arid and semi – arid regions of the world due to lack rainfall and their inappropriate distribution, which has always faced water shortage i MorePrecipitation is important climatic varibles which is directly involved the hydrological cycle. Iran is considered the most arid and semi – arid regions of the world due to lack rainfall and their inappropriate distribution, which has always faced water shortage important limitations of natural resources.Therefore, the present study was conducted with the aim of extracting scale behavior and identifying (long – term and short – term) precipitation memory of two Karkheh and Dez catchment. For this purpose, Precipitation data of two Karkheh and Dez catchment were used over a period of 60 years (1959 – 2019). The results showed that the stations both areas have 2 rainfall regimes. In the study precipitation regimes all stations, two basins were identified. The small – scale precipitation regime has a long – term memory and a stable time series. However the large – scale precipitation regimes has a short – term memory and its time series is static except Doab and Darreh Takht station. both precipitation regimes show completely different scale behavior. the relationship between precipitation scale behavior and topography of the study area was calculated using pearson correlation test. The results show that there is no significant relationship between Karkheh basin both precipitation regimes. but in Dez basin, there is a significant correlation the small – scale precipitation regime, but there is no significant correlation the large – scale precipitation regime. This can be due to the conflicting and heterogeneous topographic situation in different parts of the region in Karkheh Manuscript profile -
Open Access Article
69 - Sensitivity analysis of rivers in arid regions to changes in atmospheric elements under climate change conditions Case study: Central catchment area of Iran
forozan esvandzibaie Manochehr Farajzadeh asl Yousef GhavidelIn recent decades, climatic variables have become more pronounced, making the flow rate sensitive to these changes. This study used climatic data of 39 synoptic stations and nine hydrometric stations in the statistical period of 1994-2015 and prospective data of 2021-20 MoreIn recent decades, climatic variables have become more pronounced, making the flow rate sensitive to these changes. This study used climatic data of 39 synoptic stations and nine hydrometric stations in the statistical period of 1994-2015 and prospective data of 2021-2080. Maan Kendall test in MATLAB environment has been used to detect annual changes. Maan Kendall statistics, Sen's slope estimates, and coefficient variation have been used from the relevant formulas in the Excel environment. The results show that the trend of precipitation in region 1, temperature in region 7, and evapotranspiration in basin eight are increasing, and the most changes in flow sensitivity analysis to precipitation changes in region 8, the temperature in regions 3 and 8, and the results of sensitivity analysis to evapotranspiration parameter It is different. The temperature in the three scenarios studied had a significant upward trend, and the changes in precipitation were different in different regions, and the most changes in the decrease in precipitation were in regions 1 and 4. Manuscript profile -
Open Access Article
70 - Assessment of the Vegetation Dryness Index Based on Satellite Imagery in Sistan & Balouchestan province
kamal omidvar Masoumeh NabaviZadeh Hamid Reza Ghafarian malmiri Ahmad MazidiDecreasing of precipitation and Increasing of temperature, leads to extreme climate events such as drought which drastically impact on agricultural. Knowledge about the timing, severity and extent of drought can aid planning and decision-making. Drought indices derived MoreDecreasing of precipitation and Increasing of temperature, leads to extreme climate events such as drought which drastically impact on agricultural. Knowledge about the timing, severity and extent of drought can aid planning and decision-making. Drought indices derived from in-situ meteorological data have coarse spatial and temporal resolutions. Thus, obtaining a real-time drought condition over a large area is difficult. Therefore, drought indices which is derived from remote-sensing data, has been widely used for drought monitoring..In this study, Vegetation Drought Index (VDI) was evaluated in Sistan & Balouchestan Province To do this, Terra Moderate Resolution Imaging Spectroradiometer MODIS (MOD02HKM and MOD11A1 ), Standard Precipitation Index (SPI) and monthly precipitation data GLDAS from 2000 to 2018 were utilized to evaluate VDI.Accuracy of the Drought spatial distribution maps based on Pearson correlation coefficient was used data. Results indicate high significant correlation rate in the study area. Thus VDI, has the potential to monitor agricultural drought in the case of study and the drought indices based on remote sensing data could well use in drought early warning systems. Manuscript profile -
Open Access Article
71 - Analysis of the effect of precipitation anomalies during the occurrence of severe wet in southern Iran in the last three solar cycles
FARNAZ mashayekh hassan lashkari Seyed jamaledin Daryabary mohsen RanjbarIn this study, the impact of precipitation anomalies during the occurrence of severe and extremely severe Wet in southern Iran has been investigated. The research design involves the following steps. 1- The daily and annual rainfall data of the synoptic stations of the MoreIn this study, the impact of precipitation anomalies during the occurrence of severe and extremely severe Wet in southern Iran has been investigated. The research design involves the following steps. 1- The daily and annual rainfall data of the synoptic stations of the study area were extracted from the data of the Meteorological Organization. 2- The statistical base has been chosen to adapt to the solar cycles of a 33-year period corresponding to the years 1986-2019. 3- The number of 19 synoptic stations that had these conditions were selected. 4- Wet years were determined based on standard precipitation indices (SPI), Chinese Z (CZI), Z score (ZSI). 5- To check the anomaly of precipitation RAI index is used. 6- Based on the declared indicators, with the criteria of 30% repetition in selected stations, 6 severe wet and based on 50% repetition in selected stations, three severe wets have occurred in the statistical period of 33 years. 7- In this research, two seasons of 1992-1993 and 1995-1996 have been examined in terms of anomaly indices and other rainfall characteristics. In the wet and extremely severe years, the annual rainfall was more than two and sometimes three times the long-term average in many stations. In terms of the number of rainy days in the years 1993-1992 in 10 stations and in the wet years 1996-1995 in 17 stations, rainy days over 30 days have been recorded. However, the number of rainy days in both wet years does not show a proportional Manuscript profile -
Open Access Article
72 - Analysis of the effect of drought phenomenon on dust events in different regions of Ghazvin province
Samira Zandifar mohammad khosroshahi Zohre Ebrahimi-KhusfiThis study was conducted to investigate the effect of drought on dust events in different cities of Qazvin province. Rainfall and temperature data were used to calculate the standardized precipitation-evapotranspiration index (SPEI) and three-hourly dust events data wer MoreThis study was conducted to investigate the effect of drought on dust events in different cities of Qazvin province. Rainfall and temperature data were used to calculate the standardized precipitation-evapotranspiration index (SPEI) and three-hourly dust events data were used to calculate the number of dusty days in the study stations. Based on the Spearman correlation coefficient, the impact of dust events on the drought phenomenon was investigated by considering different time delays. The maximum correlation between SPEI and the number of dusty days in Ghazvin city without considering the time delay of -0.38 and at the level of 99%, was significant, indicating the simultaneous impact of dust events from the drought phenomenon in the center of the province. The results also showed that the response time of dust events to meteorological drought with a delay of one year in Moallem Kalayeh city is significant at 90% confidence level (r = -0.52). Meanwhile, in other cities of Ghazvin province, no significant relationship was observed between the two phenomena of dust occurrence and meteorological drought. Manuscript profile -
Open Access Article
73 - Climate change detection Persian Gulf region using data output CGCM. A1B
Zahra Hejazizadeh Mohamad salighe Samad KamaliFirst, it was determined to detect climate change of temperature, precipitation, sea level pressure and not particularly Persian Gulf, And was divided into two parts, the northern coast and South Coast. Specified period (2015-1970) was selected for the stations listed w MoreFirst, it was determined to detect climate change of temperature, precipitation, sea level pressure and not particularly Persian Gulf, And was divided into two parts, the northern coast and South Coast. Specified period (2015-1970) was selected for the stations listed were selected and were taken from the website of climate change Canada's network of station data (rainfall, temperature, heights, and not special). And then the same process was used for the next period (2050-2016). Given that the quantities mentioned factors are affecting climate change, The quantity mentioned in the current and future period, seasonally and annually were investigated based on the output of the model for all stations CGCM2.3.2a SR_A1B. The results showed that temperature changes in winter has changed dramatically in the southern part of the Persian Gulf, As predicted to rise in the coming period, roughly 3 degrees relative to the current time. In spring, temperatures are expected(Abu Musa area, Bandar Lengeh, Kish Island and western parts of the island) to increase compared to the current period in the southern coast of the Persian Gulf and The temperature will be 28 to 31 degrees Celsius.In the summer monsoon summer dominated by an increase in temperature across the Persian Gulf as the total area, the temperature is between 30 and 38 degrees Celsius. This chapter also predicts that in the coming period will be automatically increased as temperatures increase. In the autumn season is also expected to be higher than 28 ° C extended temperature zones and involve large part of the Persian Gulf. Manuscript profile -
Open Access Article
74 - Evaluation of air temperature and precipitation changes in the rainy region of western Iran under climate change conditions
Sadi Abdoli Ghasem Azizi Reza BornaThe phenomenon of climate change is one of the vital issues for human beings today. Investigation of air temperature and precipitation in the second rainiest region of the country, namely the western half; It is important. In the present study, observational data of 51 MoreThe phenomenon of climate change is one of the vital issues for human beings today. Investigation of air temperature and precipitation in the second rainiest region of the country, namely the western half; It is important. In the present study, observational data of 51 meteorological stations in the region were used as baseline data. For the next period up to 2061 horizon, the output of simulation models in the fifth report of climate change was used in two models of induced upper and middle limits, as microscale data. The non-parametric Man-Kendall test was used to investigate the trend of changes in air temperature and precipitation series. The results showed that in the base period based on observational statistics, in most areas in the series and the pattern of air temperature, there is a significant upward trend. For rainfall, a significant decreasing trend was observed in most areas and a negative slope was observed in all stations. Evaluation of the output of the models in comparison with the base period showed that in the western and Zagros regions of the country, the minimum and maximum air temperatures in the coming decades in the upper and middle limits pattern, respectively, will increase by 3.1 and 1.1 ° C, respectively. Will have. Precipitation in some stations will increase slightly in the spring months, but in the annual pattern in most areas the precipitation will be lower than the base period. Therefore, the rainy region of the western half in the Zagros region of Iran will be accompanied by an increase in air temperature and a decrease in precipitation. Manuscript profile -
Open Access Article
75 - Detection of air temperature and precipitation changes in Kohgiluyeh and Boyer-Ahmad provinces under climate change conditions using MIROC5 model
Ahmad Fakhir Nasab Behlol Alijani Farideh AsadianThe abnormalities and the occurrence of climate hazards, the importance of the phenomenon of climate change is becoming increasingly apparent. Changes in air temperature and precipitation play a significant role in detecting the effects of climate change. In this study, MoreThe abnormalities and the occurrence of climate hazards, the importance of the phenomenon of climate change is becoming increasingly apparent. Changes in air temperature and precipitation play a significant role in detecting the effects of climate change. In this study, the perspective of changes in air temperature and precipitation in Kohgiluyeh and Boyer-Ahmad provinces was evaluated with a statistical approach. In this regard, the statistics of weather stations in the period (1986-2015) was used as the base period. For future period, the output of the MIROC5 as general circulation model (GCM) under RCP8.5 and RCP4.5 scenarios in the form of downscaled data from the MarksimGCM database was used. Results of projecting the future period in the form of high and medium radiative forcing scenarios (RCP) shows an upward trend in the minimum and maximum temperatures of the study area in the future period compared to the base period. This incremental deviation is greater in the decades relative to the present period. Spatially to the time horizon 2061; areas with cooler and warmer temperatures will be added in the province. From the low altitudes or southern part of the province, with the passage to the following decades, the range of milder and warmer temperatures will gradually increase compared to the base period. The Precipitation parameters in the coming period will face a sharp and significant decrease compared to the base period, especially in the wet months of the year. This rainy region of high Zagros range,will face a significant decrease in rainfall in the coming period. Manuscript profile -
Open Access Article
76 - The Role of Topography in Intensification of Precipitations in the south and South-west of Iran((Case Study:3 December 2015))
zynab mohammadi hasan lashkariIn this study, 10 precipitation systems were selected as prototypes between October and June 2016-2015. Then, 70 stations from the country's satellite stations were divided into four general groups in the south, southwest and center of Iran. The daily precipitation of t MoreIn this study, 10 precipitation systems were selected as prototypes between October and June 2016-2015. Then, 70 stations from the country's satellite stations were divided into four general groups in the south, southwest and center of Iran. The daily precipitation of the stations was extracted from each platform. To determine the patterns of precipitation occurrence in the Sudan low pressure region, atmospheric data from 1000 to 500 HPa are extracted from the NCEP / NCAR site and in the GRADS the maps of these ten systems were mapped. One of the most important systems that provide rainfalls in the Middle East is Sudan low pressure Lashkari (1996). The results showed that the systems entering Iran and the Middle East from the mentioned Sudan low pressure have a special mechanism. These systems have strong convection mechanisms because of having a thermal nature in their source and receiving a huge amount of moisture from the surrounding warm seas. They form deep boiling clouds and cause intensive and torrential showers when accompanied by deep waves in layers 700 and 850 HPa. Therefore, the cloud always forms in a convective way, and the height does not play a significant role in the intensification of its precipitations. In other words, it does not have a significant role by itself, at least in the windward slopes of the Zagros Mountains. The intensity of precipitation is, therefore, sometimes higher in the plains compared to the mountain summits. It seems heights play a more effective role in elevations above 1,500 meters in both windward and leeward slopes. However, in the Alborz mountain chain, there is a very clear and impressive correlation between precipitation and height because of re-creation of systems Manuscript profile -
Open Access Article
77 - Evaluation of Interpolation Indexes in Droughts Using GIS (Case Study Larestan)
Marzieh MogholiDrought is one of the most important environmental events and also it’s the integral part of climate fluctuations. This phenomena is a specific condition of precipitation loss and high temperature that might happen in every climate condition. Drought condition awa MoreDrought is one of the most important environmental events and also it’s the integral part of climate fluctuations. This phenomena is a specific condition of precipitation loss and high temperature that might happen in every climate condition. Drought condition awareness and drought intensities zoning might decrease risks of drought losses significantly. Present study is an attempt to evaluate accuracy of place interpolation methods for occurred drought intensities zoning in LARESTAN in 1387 using Percentage of normal precipitation Index (PNPI), standard precipitation index (SPI), deciles precipitation index (DPI), and Rainfall anomaly index (RAI). Therefore, it used data of 20pluviometry stations in LARESTAN that distributed appropriately and inverse distance weight (IDW) with 1 to 3 powers, ordinary kriging (OK), and universal kriging (UK) Methods, were studied Manuscript profile -
Open Access Article
78 - FutureProjection of temperature and precipitation changes in the southern coast of Caspian sea
مریم کثیری مسعود گودرزی مسعود گودرزی غلامرضا جانباز قبادی غلامرضا جانباز قبادی صدرالدین متولی صدرالدین متولیTemperature and precipitation are among the most important climatic elements in the study of climate change due to significant temporal and spatial changes, and the projection of their changes is agreat importance in environmental planning and hazards. Therefore, in thi MoreTemperature and precipitation are among the most important climatic elements in the study of climate change due to significant temporal and spatial changes, and the projection of their changes is agreat importance in environmental planning and hazards. Therefore, in this study, future projection of temperature and precipitation changes in the southern cost ofcaspian sea was investigated. For this purpose, the data of CanESM2 model was used under three scenarios (RCP2.6, RCP 4.5 and RCP 8.5) using the SDSM downscaling model the temperature and precipitation changes in three different periods (2021-2050, 2051-2080- and 2081-2100) were examined in relation to the basic period (1989-2018). To calibration and validation the SDSM model, stationary observation data and NCEP data were used, as well as MAE, MSE, RMSE and R2 indicators. The results showed that the SDSM model has the ability to simulate temperature and precipitation changes in the study. Based on the results of the CanESM2 model output, the minimum and maximum temperatures will be increase in all studied periods and each period compared to the previous period, the average amount for the minimum temperature is 2 oC and for the maximum temperature, it will be 2.2 oC compared to the base period. Most of the temperature changes are related to the western regions of the study area. The projection of precipitation changes also shows that except ofGorgan station in other stations study, the amount of precipitation will decrease in all future periods compared to the base period, the average of which will be during the next period (2021-2100),Will be equal to 3.6%. Most of its changes are related to the central and western areas of the study area. Also, the RCP8.5 scenario showed the most changes in temperature and precipitation. Manuscript profile -
Open Access Article
79 - An Agro-Climatic Zoning of dryland whea Based on the date of the first rainfall 10 mm In the cultivation season in Kermanshah
Rastegar Mohammadi Javad Khoshhal Dasjerdi Daryosh RahimiClimate is the most important factor that determines the type of crop to planting in each region. Due to the fact that the cultivation of dryland wheat is a priority in the province, this study was selected. In this study, climatic data of 6 synoptic stations (1989-2012 MoreClimate is the most important factor that determines the type of crop to planting in each region. Due to the fact that the cultivation of dryland wheat is a priority in the province, this study was selected. In this study, climatic data of 6 synoptic stations (1989-2012) and 8 climatology stations (2008-2013) were used. Due to the date of the beginning of autumn rains, planting date was suggested for each region of the province. Then different types of probabilistic distributions were fitted to the planting date. The best statistical distribution was selected from the coefficient of determination and different growth stages of dryland wheat were determined. From the precipitation element, the required types of precipitation maps were extracted. Also from the temperature element, various temperature maps and temperature stresses were prepared. Finally, climatic zoning map of dry land wheat were extracted and from this map the areas with no potential of cultivation were omitted. The final map comprised four very good, good, medium and weak areas. And maps of zoning for 5 mm Precipitation revealed that very suitable area for cultivation of wheat was located in some parts of the Northwest, West and South west of Kermanshah province. And suitable areas, was in the Northwest, West, Southwest and medium areas was located in Southwest, West,Center, North, Northeast, and southeast, And weak areas are often located in center and northeast. Manuscript profile -
Open Access Article
80 - Classification of changes in the length of rainfall-dependent dry periods in Iran
seyed keramat hashemi anaTo study the behavior of dry period lengths, precipitation data were used on a daily scale for 45 synoptic stations in Iran (1985-2017). In order to spatially distribute the dry periods, sequences of 10, 20, 30 and more than 30 days were used and turned into zones. The MoreTo study the behavior of dry period lengths, precipitation data were used on a daily scale for 45 synoptic stations in Iran (1985-2017). In order to spatially distribute the dry periods, sequences of 10, 20, 30 and more than 30 days were used and turned into zones. The results showed that the highest frequency of long-term dry periods (30 days and more), with 86 events is related to the south-eastern part of Iran and Iranshahr station. The lowest frequency with 3 cases belonged to Rasht station on the southwest coast of the Caspian Sea in northern Iran. The second-order Markov probability distribution was used to evaluate the type of dry period distribution, return continuity and their probability of occurrence. Probability matrix and return period for 10, 20 and 30 day continuities were calculated on a monthly scale and it was determined that June and April were the shortest dry period return periods (18 days) in the arid central and eastern regions of the country with the highest probability of occurrence ( 89%) and the longest return period is related to October and November in the wetlands of the north and northwest coast of the country (338 days) and the lowest probability of occurrence (28%). Manuscript profile -
Open Access Article
81 - Trend Analysis of Extreme Climate Changes Index’s in Precipitation and Temperature in Bushehr Province
Reza Borna Aigin JahanClimate variability and change behavior of extreme events is important. To review some events, some climate indices for the detection surface by the Working Group on Climate Change and the World Meteorological Organization and climatology Committee research program on c MoreClimate variability and change behavior of extreme events is important. To review some events, some climate indices for the detection surface by the Working Group on Climate Change and the World Meteorological Organization and climatology Committee research program on climate variability and predictability are introduced. In this paper, the changes in temperature and precipitation at the weather station 6 Bushehr Province during the period 1391-1371 using threshold values, and the nonparametric Mann-Kendall test for the presence of a linear trend has been used. The results show, Bushehr is highly exposed to the mean temperature, the frequency profile so reducing heating and cooling profiles. Cold nights and warm nights to other index increased thresholds of them have been impressive. Prolonged periods of increased summer heat in recent decades to a great show. DTR drop in the station area, tropical nights and warm nights increase in the length of the stations there. The research findings showed that: During the study period, a negative trend for the series of one-day maximum precipitation (Rx1day), maximum 5-day precipitation (Rx5day) and the simple daily intensity (SDII) can be seen in the province. The R10 index in research stations with positive trends. Check the index R20 and R25, shows that during the period studied, the research station has negative trends in the linear gradient. CDD index of consecutive dry days with precipitation have also increased in recent years coordinated. CWD index showed a decrease in rainfall in the region in recent years, coordinated by the number of consecutive wet days (CWD) is greatly reduced. Indexes Series R95 p and R99 p represent the province at the station volatility and decline in the latter years of the study period. Trends in Bushehr Province PRCPTOT index shows that the average rainfall in this region is low, thus decreasing trend is coupled with high volatility Manuscript profile -
Open Access Article
82 - Climatic Classification for Hormozgan Province Based on Litynski Method
صدیقه پرون صدیقه پرون غلامرضا یاوری غلامرضا یاوری مریم رضازاده مریم رضازادهTraditional climate classification methods are very diverse. Despite their historical and comparative importance, these methods have weaknesses that reduce their efficiency. Implementing sustainable developments in disadvantaged areas in need requires precise planning b MoreTraditional climate classification methods are very diverse. Despite their historical and comparative importance, these methods have weaknesses that reduce their efficiency. Implementing sustainable developments in disadvantaged areas in need requires precise planning based on talents and resource constraints. The climate of each region is one of the most important determinants of local development potentials. The purpose of this research is to determine the climate of Hormozgan province based on the Litynski method which is described in this paper. In the Liyinski system, three primary elements of temperature, precipitation and barry coefficient are used. This method utilizes auxiliary indicators for categorical comprehensiveness, which includes three indicators of the coincidence, a dry season and the state of sunlight. Required data were collected from seven weather stations of Hormozgan province including Haji Abad, Minab, Bandarlenge, Qeshm, Rudan, Jask and Bandar Abbas during the years 2002-2017 and used in Excel and SPSS environment. Finally, the climate of stations was estimated using five indicators. The results showed that the two stations of Bandar Abbas and Qeshm are more similar in terms of climate. Rudan has a warm tropical climate based on temperature division. Jask also has the most dry months. Regarding the compliance index of all stations, the main precipitation is in the cold season. In terms of the radiation status index, the same results were obtained for all stations. Manuscript profile -
Open Access Article
83 - Change Time Study Pricipitain of Hamadan Province Using Statistic’s and Neural Network Methods
Zohreh Maryanaji Hamed AbbasiClimate change is one of the common problems in today’s societies and considerate as threat for earth. Increasing of earth temperature is cased to extensive changes in earth climates and also it laded to same variations of spatial and temporal of precipitation so MoreClimate change is one of the common problems in today’s societies and considerate as threat for earth. Increasing of earth temperature is cased to extensive changes in earth climates and also it laded to same variations of spatial and temporal of precipitation so that these variations cased to a lot of damages especially in last decade. This study to identify of variations and the trend of season and duration of precipitation in different times intervals. Then it is predicted same changes in the future by the method of artificial neural network. In this study we have us of the data from two synoptic stations Hamadan and Nojeh .The statistic’s years in this study; it seems the rainfall season in the central part of Hamadan province in started later and ended later in last decade. In other words the starter of rainfall season in Hamadan which occurred in the fall season, at present tend to ward the winter season and the fall season is more dryer than before ages. This shows that the rainfall season is interchanged in this district. in using of the method of artificial neural network we should consider to two main points in the predicting of precipitation the first one, the low attention of this method in the long –term predicting of precipitation and the second one, the exaggerate in the minimum and maximum amount of precipitation in different seasons of year. Manuscript profile -
Open Access Article
84 - Assessment of NARX Neural Network in Prediction of Daily Precipitation in Kerman Province
Kamal Omidvar Maasomeh Nabavizadeh Meysam SamarehghasemPrecipitation is one of important parameters of climatology and atmospheric science that have more importance in human life. recently, extensive flood and drought entered many damage to most parts of the world. Precipitation forecasting has important role in management MorePrecipitation is one of important parameters of climatology and atmospheric science that have more importance in human life. recently, extensive flood and drought entered many damage to most parts of the world. Precipitation forecasting has important role in management and warning of this problem. Due to the interaction of various meteorological parameters in the calculation of rain, leads it to a very irregular and chaotic process. The purpose of this study, assessment of forecasting precipitation, using data from meteorological stations of the using common statistical period (2012-1989) in Kerman, Baft, Miandeh Jiroft. In this way, to the training of the artificial neural networks with structure Perceptron, Nonlinear Autoregressive External. Effective Factors in the rain, as input for Artificial Neural Networks and precipitation was considered as the output of the Network. Statistic indicators MSE, R were used for performance evaluation of the models. The analysis of output results from, Nonlinear Autoregressive External Neural Networks shown that these models have better accuracy and a high ability to forecast precipitation than Perceptron Neural Networks. The results showed the more exact method concerned to the (NARX) model. The 42 models with all parameters with Levenberg Marquat rule and sigmoid function had the best topology of the model in three stations. Overall, evaluation of NARX results showed that the errors of ANN were negligible. The NARX showed high sensitivity to relative humidity. Manuscript profile -
Open Access Article
85 - Analysis and Comparison of SPI and GRI Indices in Assessing Meteorological Drought and Groundwater, Case Study: Mehran Plain, Ilam Province
Ali Abbasinia jafar morshedi Mnizheh Zohoriyan Jebrael GhorbaniyanDroughts are one of the most devastating weather events, causing significant damage to both natural resources and human life. The purpose of this study is to analyze and compare meteorological drought and groundwater of Mehran plain using standardized precipitation inde MoreDroughts are one of the most devastating weather events, causing significant damage to both natural resources and human life. The purpose of this study is to analyze and compare meteorological drought and groundwater of Mehran plain using standardized precipitation index (SPI) and groundwater index (GRI). In order to study the meteorological drought, the monthly rainfall information of Mehran synoptic station was used and in order to study the dryness of the groundwater of Mehran plain, the changes of groundwater level of Mehran plain were analyzed based on water level data of 23 observation wells. Also, SPI index was used for meteorological drought monitoring and GRI index was used for hydrological drought monitoring of Mehran plain. The statistical period required for drought analysis of a 25-year statistical period from the water year of 75-74 to 97-96 was selected. After determining the moisture periods of the indices, monthly groundwater zoning maps were prepared. To prepare these maps, the kriging model was selected from among different models. Finally, by applying the optimal half-change model in kriging and entering groundwater data as a point layer, raster maps were prepared using Arc GIS software. The results of the study of SPI index show that during the statistical periods in question, 4 severe droughts occurred, the most severe of which was 90-91, with a value of SPI index of -1.73. Also, the results obtained from the GRI index in the region show that an 11-year drought period of groundwater occurred, ie it started from the water year 88-87 and continued until the water year 98-97, the most severe of which was 90-91 with the amount of The index is -1.11. Manuscript profile -
Open Access Article
86 - Classification of residential and tourism comfort using climatic indicators (Case study: Ilam province, Iran)
Ali Arefi Mohsen Ranjbar Reza BornaIdentifying areas prone to residential comfort and tourism based on climatic parameters is one of the most used topics for climate, geography and tourism researchers. Considering the importance of the topic, the current study aimed to classify the climatic and tourism c MoreIdentifying areas prone to residential comfort and tourism based on climatic parameters is one of the most used topics for climate, geography and tourism researchers. Considering the importance of the topic, the current study aimed to classify the climatic and tourism comfort using climatic indicators in Ilam province. First, using climatic data of rainfall, temperature, relative humidity and speed from six synoptic stations, descriptive statistics were analyzed. The statistical period of the study case was 30 years (water year 2010-2018 to 2019-2019). Next, using Baker's climatic indices, effective temperature and probability distribution, the degree of climatic comfort was determined for each month. This research analyzed the consequences of changes in temperature and precipitation on the climatic comfort of Ilam province in terms of geographical territory. The results of Baker's climatic indices, effective temperature and probability distribution showed that the months of April, May, October, November and March are prone to climatic comfort. According to the results, the cities of Darreh Shahr and Lomar have the greatest potential for climatic comfort in the months of transition from heat to cold (October and November) and cold to heat (April and May). In general, the northern and eastern cities of Ilam province have higher climatic comfort in spring and autumn. On the other hand, in winter season, the southern and border cities (Mehran and Dehloran) have a comfortable climate. Manuscript profile -
Open Access Article
87 - Investigation of arid vegetation compatibility toward precipitation variation with NDVI index (a case study, Ardakan-Aghda plain)
منیرالسادات Tabatabaii Zadeh فاطمه Hadian S.Z Hosseini جلال Barkhordari حسن KhosraviDrought monitoring is a important management program, but have some limitation as economical, huge and arduous natural areas. Then nowadays have been used satellite images for drought monitoring and management of areas as fastest and low cost method. In this research ha MoreDrought monitoring is a important management program, but have some limitation as economical, huge and arduous natural areas. Then nowadays have been used satellite images for drought monitoring and management of areas as fastest and low cost method. In this research have been used NOAA satellite images and annual/seasonal precipitation data during 2005-1982 then studied effect of Precipitation on vegetation cover in a part of Yazd province (Ardakan- Aghda area). The 92 precipitation maps have been prepared For determination of precipitation value in every vegetation type by using climate data and classified by distance weighting interpolation method. The results show an alone vegetation index could not define vegetation cover of study area that necessary to used multi-regression methods with other climatic factors. Furthermore, this index is not useful for arid area because have very low correlation between INDVI index and precipitation then is necessary to use other indexes and satellite images with more quality. Manuscript profile -
Open Access Article
88 - Application of TiO2/ZnS as a nano photocatalyst for degradation of Acid Red 18 in aqueous media using a central composite design
Aref Shokri Mahdi Sanavi Fard -
Open Access Article
89 - Employing ZnFe2O4 as a nano photocatalyst for degradation of Tert- Butyl alcohol in synthetic wastewater
Ali hassani joshaghani Fariba Soleimani Mahdi Sanavi Fard Aref Shokri -
Open Access Article
90 - Photocatalytic degradation of Congo Red dye by using nano ZnO and Ni-Co-ZnO nanocomposites
Sara Poorarjmand Maryam Kargar Razi Ali Reza Mahjoob Morteza Khosravi -
Open Access Article
91 - Wet chemical synthesis and physical characterization of doped CeO2 nanoparticles
J. Jasmine Ketzial A. Samson Nesaraj -
Open Access Article
92 - The effect of different pHs, Surfactants and dialyses times on preparation of nano Rod Hydroxyapatite
Fateme Mirjalili -
Open Access Article
93 - Using ZnO based on Bentonite as a nano photocatalyst for degradation of Acid Red 114 in synthetic wastewater
Reza Hekmatshoar Ahmad Reza Yari Aref Shokri -
Open Access Article
94 - Climate change impacts on nitrogen and phosphorus loading in New England watersheds
Jenna Baker Timothy Randhir -
Open Access Article
95 - Pilot scale study of Co-Fe-Ni nanocatalyst for CO hydrogenation in Fischer-Tropsch synthesis
Hamid Reza Azizi Ali Akbar Mirzaei Razieh Sarani Massoud Kaykhaii -
Open Access Article
96 - P-type semiconducting NiO nanoparticles synthesis and its photocatalytic activity
Alireza Heidarineko Azar Bagheri Ghomi -
Open Access Article
97 - Enhancement of photocatalytic degradation of 4-nitrophenol by integrating Ag nanoparticles with ZnO/HZSM-5 nanocomposite
Baharak Divband Azadeh Jodaei Masumeh Khatamian -
Open Access Article
98 - Synthesis of Fe-doped TiO2 with improved photocatalytic properties under Vis-L irradiation
Imane Ellouzi Boutaina Regraguy Souad El hajjaji Mourad Harir Philippe Schmitt-Kopplin Hinda Lachheb Larbi Laânab -
Open Access Article
99 - Facile wet chemical synthesis and characterization of zinc doped gadolinium oxide nanoparticles for enhanced photodegradation of Rhodamine B dye under illumination of UV light
Leena Vinolia Thaninki Arputharaj Samson Nesaraj Manasai Arunkumar -
Open Access Article
100 - Development of a Wavelet Hybrid Models for Estimating Regional Droughts in Siminehroud Basin
Erfan Rostam Zade alireza parvishiIn the present study, the drought of Siminehroud basin was investigated by intelligent Support Vector Machine (SVM) models, Artificial Neural Network (ANN) and Wavelet theory (W). Data from six rain gauge stations in the region were used and drought index was calculated MoreIn the present study, the drought of Siminehroud basin was investigated by intelligent Support Vector Machine (SVM) models, Artificial Neural Network (ANN) and Wavelet theory (W). Data from six rain gauge stations in the region were used and drought index was calculated in four time scales. The first-order autocorrelation was also selected as the optimal delay. Then the appropriate structure of the Artificial Neural Network was determined using Trial and Error Method and the three coefficients of the SVM model were determined and modeled. The results of evaluating individual models showed that there is no significant difference between two methods in predicting droughts. Then WANN and WSVM hybrid models were prepared. The results showed that the application of Wavelet theory greatly improved the performance of individual models and the amount of RMSE and MAE indices decreased by 19% and 21% and the correlation coefficient increased by 30%, respectively. Manuscript profile -
Open Access Article
101 - Drought in Gorgan Synoptic Station. Estimation and Analysing
Hossein Mohammadi Mohsen Soltani Ali HanafiDrought is the most important kinds of natural hazards and it is a secret and slow phenomena which results from climate processes. The intensity and frequency of it depends on geographical position. it occurs due to decrease of raining rate once at several years. In ord MoreDrought is the most important kinds of natural hazards and it is a secret and slow phenomena which results from climate processes. The intensity and frequency of it depends on geographical position. it occurs due to decrease of raining rate once at several years. In order to study of Gorgan station droughts we used from Meteorological organization data for a period (1976-2005).After primary investigation, drought was analysed by using of standard distribution, Percentage Normal and Deciles, so that it was extracted the weak and intermediate droughts and its trend on station. Results showed that 85-95 decades were the driest decade in statistical duration and according to used indexes, the year of 1990 had the severest drought value. Manuscript profile -
Open Access Article
102 - The Effects of Climate Change on Iran's Sugarcane Production (Case study: Khuzestan Sugarcane)
Abdulah Rajabalinejad Niv Nozari Bita Rahimi BadrClimate change due to global warming cause a lot of concern that requires comprehensive and reciprocal world wide action. The agricultural sector is one of the most dependent sectors on the climate, in the production cycle and food security of Iran, with a dry and hot c MoreClimate change due to global warming cause a lot of concern that requires comprehensive and reciprocal world wide action. The agricultural sector is one of the most dependent sectors on the climate, in the production cycle and food security of Iran, with a dry and hot climate is at a higher risk of global damages for these climate changes. Moreever, the major sugarcane industries of Iran are located in Khuzestan province which climatic variables in this region have recorded drastic and increasing changes procedure. In this article the effects of climate change on sugarcane industry in Khuzestan are studied (1971-2020). The usage of Dynamic Ordinary Least Squares (DOLS), an econometric model, helped examining the effect of climate factors such as temperature and precipitation on production. The results depicts a nonlinear relation between the climatic factors temperature and precipitation and production. As a matter of fact, the nonlinear relation in the form of an inverted U-shape in the graph shows the importance of climate change on agricultural production. The government's ownership of Khuzestan's sugarcane cultivation and the assignment of exclusive rights should provide maximum productivity, but not achieving an ideal goal. In conclusion, because of the negative effects of climate change on sugarcane production, it, is highly recommended to 1) Limit human intervention in nature, 2) Utilize varieties of other crops which are more resilientistant to climate change, 3) Alternate the cultivation patteren,and finally (4) To consider supportive policies in this matter to cope with the effects of climate change . Manuscript profile -
Open Access Article
103 - اثر تغییرات آب و هوا بر هزینههای مواد غذایی خانوارهای روستایی ایران
علیرضا کرباسی چیمن صیادیاین پژوهش به بررسی تغییرات آب و هوا بر هزینه مواد غذایی خانوارهای روستایی در ایران میپردازد. هزینه موادغذایی خانوارهای روستایی ایران به عنوان تابعی از متوسط درآمد خانوارهای روستایی، شاخص قیمت خرده فروشی مواد غذایی، هزینه موادغذایی خانوارهای روستایی، سطح زیرکشت و آب و Moreاین پژوهش به بررسی تغییرات آب و هوا بر هزینه مواد غذایی خانوارهای روستایی در ایران میپردازد. هزینه موادغذایی خانوارهای روستایی ایران به عنوان تابعی از متوسط درآمد خانوارهای روستایی، شاخص قیمت خرده فروشی مواد غذایی، هزینه موادغذایی خانوارهای روستایی، سطح زیرکشت و آب و هوا با استفاده از روش پانل پویا و نرمافزار Stata11برای 26 استان کشور بررسی شده است. بارندگی، دما و رطوبت نسبی به عنوان شاخص­هایی برای متغیر آب و هوا در نظر گرفته شده است. نتایج نشاندهنده تأثیر معنیدار و مثبت متوسط درآمد خانوارهای روستایی، شاخص قیمت خرده فروشی مواد غذایی، هزینه مواد غذایی خانوارهای روستایی با یک وقفه و بارندگی بر هزینه مواد غذایی خانوارهای روستایی است، سطح زیرکشت و رطوبت نسبی بر هزینههای مواد غذایی خانوارهای روستایی اثر نداشته است و دما اثر منفی و معناداری بر هزینههای مواد غذایی خانوارهای روستایی دارد. در پایان با توجه به تأثیری که هر کدام از متغیرهای گفته شده به طور صریح بر هزینه مواد غذایی خانوارهای روستایی و بطور ضمنی بر امنیت غذایی این خانوارها دارند پیشنهادهایی برای حفظ و همچنین بهبود امنیت غذایی در خانوارهای روستایی ارائه شده است. Manuscript profile -
Open Access Article
104 - Synthesis of cobalt ferrite nanoparticles and investigation of magnetic hyperthermia properties at different concentrations
Salah Khanahmadzadeh kamran heydaryanIn this paper, cobalt ferrite nanoparticles were synthesized using a co-precipitation method. The properties and characteristics of the cobalt ferrite nanoparticles were studied using XRD, VSM, and FESEM analyses. The FESEM images showed that the cobalt ferrite nanopart MoreIn this paper, cobalt ferrite nanoparticles were synthesized using a co-precipitation method. The properties and characteristics of the cobalt ferrite nanoparticles were studied using XRD, VSM, and FESEM analyses. The FESEM images showed that the cobalt ferrite nanoparticles had almost spherical morphology, and that the particle size distribution (determined with the help of Digimizer software) was in the range of 25–60 nm. Moreover, the average size of the nanoparticles was calculated to be in the range of 37-47 nm. The VSM results indicated superparamagnetic properties of the cobalt ferrite nanoparticles at room temperature. Besides, the saturation magnetization and coercivity were found to be 30 emu/g and 39 Oe, respectively. The specific loss power (SLP) was investigated by preparing ferrofluid concentrations of 3, 5, and 8 mg/ml under a magnetic field of 400 Oe and at a frequency of 400 kHz. In this case, the rate of the increase in temperature of the cobalt ferrite nanoparticles was measured in a certain period of time, and the related SLP was calculated. The results of the measurements showed that the highest rate of the heat generation occured at the concentration of 8 mg/ml, leading to an SLP value of 162 W/g. Manuscript profile -
Open Access Article
105 - Continuous and controlled production of dexamethasone nanoparticles in a microfluidic system
payam zahedi maryam tabatabai morteza fathi pour amin sohrabiThe aim of this work is to produce continuously dexamethasone nanoparticles (DEX NPs) in a microfluidic (MF) system via nanoprecipitation method to control particle size, possessing their physical structure, and enhancing the efficiency of this hydrophobic drug in physi MoreThe aim of this work is to produce continuously dexamethasone nanoparticles (DEX NPs) in a microfluidic (MF) system via nanoprecipitation method to control particle size, possessing their physical structure, and enhancing the efficiency of this hydrophobic drug in physiological environments. In order to fabricate a MF chip, a series of microchannels with dimensions 1 cm in length, 200 μm in width, and 50 μm in depth are embedded using ultraviolet soft lithography on a sheet based on polydimethylsiloxane (PDMS), and then the laminar fluid flow ability is investigated through it. The effective factors on the optimized production of the drug NPs are determined by the design of experiment. In this line, the optimum values for drug solution concentration, surfactant concentration, drug solution flow rate, and non-solvent flow rate are 15 mg/ml, 1 mg/ml, 4.5 ml/h, and 8 ml/h, respectively. By adjusting these values the average sizes of DEX NPs are obtained 590 ± 20 nm based on the model and 500 ± 20 nm according to the experiments. In the following, the results of dynamic light scattering (DLS) test show the narrow size distribution of DEX NPs fabricated using the MF chip. Also, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) assays reveal that application of the MF system does not affect the crystallinity of the drug NPs and does not alter their structure after the process. Finally, MF-assisted DEX NPs sample shows the drug solubility rate of about 8-fold compared to the commercial powder ones Manuscript profile -
Open Access Article
106 - Synthesis of nanoporous molecularly imprinted polymers for extraction of naringenin compound
مینا هویه گر علیرضا امیری محسن جهانشاهیIn this research for the first time, an adsorbent based on molecularly imprinted polymers )MIPs( for selective extraction of Naringenin using methacrylic acid )functional polymer(, trimethylolpropane trimethacrylate )cross linker(, azobisisobutyronitrile )initiator( via MoreIn this research for the first time, an adsorbent based on molecularly imprinted polymers )MIPs( for selective extraction of Naringenin using methacrylic acid )functional polymer(, trimethylolpropane trimethacrylate )cross linker(, azobisisobutyronitrile )initiator( via precipitation polymerization technique in a ratio )1:4:20( were synthesized. After template removal, nanoporous imprinted polymeric lattice was prepared which is able to extract Naringenin as a bioactive compound from the mixtures containing this component. Non-imprinted polymers )NIPs( with the same materials )instead of the template molecule( were synthesized to compare the efficiency of the MIPs. Selectivity of the MIPs for Naringenin has been evaluated. Quercetin as a similar molecule of the template was selected which the binding capacity for Naringenin and Quercetin were 284 mg.g-1 and 70 mg.g-1, respectively. Imaging scanning electron microscope )SEM( was used for morphological studies on the synthesized polymer particles and brannauer-emmet-teller (BET) analysis method was applied to measure the porosity, specific surface area and poor diameters of the polymer Manuscript profile -
Open Access Article
107 - The synoptic study of heavy rain fall (200mm or more during 24 hours) over the southern coasts of Caspian Sea due to mean temperature of thickness 1000/500mb, in 2th of October 2001
H. Ardakani M. Poratashi M. KheirandishThe mean annual precipitation over the southern part of Caspian coastal area is around 1000-1500 mm; therefore, this amount of precipitation is very important and is a considerable point of attention. With reference to statistical data, during 30 years (1972-2001), it MoreThe mean annual precipitation over the southern part of Caspian coastal area is around 1000-1500 mm; therefore, this amount of precipitation is very important and is a considerable point of attention. With reference to statistical data, during 30 years (1972-2001), it showed that there were only 10 cases of similar events. We found that, best synoptic patterns for this condition is the mobile cold anticyclones which is moving almost rapidly from Europe and Scandinavia to the north of Black Sea and then moving to the Caspian Sea. These anticyclones have strong cold advection in eastern part and warm advection in the western part and their pressure center are about 1040 mb or more. But those anticyclones are very slow moving or almost stagnant over the area and could not cause these events. The upper-air chart showed that, spatial axis of upper ridge over them is a normal baroclinic condition. The value of cold advection in eastern part of anticyclones computed from 700 mb was -12ºc/12hours, but warm advection in western part of them, were not the same values. Consequently, the month of October is the most effective with compassion of the other months, because, during the summer times (July, August, September). The thermal low over the country frequently extending over the Caspian Sea and SST will increase, so, such patterns with strong cold advection, will cause severe instability over Caspian Sea. Manuscript profile -
Open Access Article
108 - Study of influence of Arctic Oscillation (AO) Index on Siberian High Pressure and their probable impacts on precipitation in southern coastal region of Caspian Sea
T. Azizian A. AskariIn this research, to investigate the relationship between AO (Arctic Oscillation) index and Siberian high pressure and the impact of it on the amount of rainfall in seven synoptic stations that have the ability to cover the southern coasts of Caspian Sea, we used 30- ye MoreIn this research, to investigate the relationship between AO (Arctic Oscillation) index and Siberian high pressure and the impact of it on the amount of rainfall in seven synoptic stations that have the ability to cover the southern coasts of Caspian Sea, we used 30- year period (1976 to 2005) precipitation data of those stations using correlation and regression analyses. We also used mean sea level pressure maps to analyze synoptically some special cases of extreme rainfalls. Our obtained results showed significant correlation at 95% level between extreme rainfalls and AO indices and also between rainfall and extreme AO indices in some stations of this region at monthly, seasonal and annual scales. In this context, using multiple regression analysis, rainfall was considered as the dependent variable and features of Siberian high pressure considered as independent variables. Results of this analysis showed that there is a strong relationship between precipitation and features of Siberian high pressure for eastern stations of the region under study in January and February. This relationship was quite evident for western stations in October. In most cases, coefficient of correlation of rainfall with central pressure of Siberian high was negative and, with latitude it was positive. Multiple regression analysis between AO indices and features of Siberian high pressure showed negative relationship between central pressures in Siberian high with AO indices and positive relationship between longitude of Siberian high pressure centers and AO indices in most months of autumn and winter. Manuscript profile -
Open Access Article
109 - The analysis of seasonality and seasonal precipitation anomaly changes in Iran during 1977-2006
S. ZarrinkamarMajd P. S. Katiraie-BoroujerdyRainfall change as a result of climate change is one of the important issues of recent decades. Climate change can be represented as changes in the inter-annual precipitation distribution and seasonality. Furthermore, the seasonality changes and the transposition of the MoreRainfall change as a result of climate change is one of the important issues of recent decades. Climate change can be represented as changes in the inter-annual precipitation distribution and seasonality. Furthermore, the seasonality changes and the transposition of the seasonal precipitation are very important for agricultural and hydrological domains decision makings. In this paper, in order to quantitatively investigat the inter-annual distribution of precipitation, at first the seasonality index and the normalized seasonal precipitation anomaly are calculated. For this purpose the monthly rainfall of 33 synoptic stations are used over Iran. The spatial distribution of the seasonality index average and also the year occurrence of maximum and minimum index for each station are identified. Then the significant trends of seasonality indices and also the normalized seasonal precipitation anomaly are examined using Mann-Kendall test for the period 1977-2006.The results show the minimum seasonality index for Gorgan station in the south east of the Caspian Sea, and the maximum seasonality index for Bandarabas station in the south of the country (the coast of the Persian Gulf). The precipitation tends to be concentrated in few months of the year in most stations for the study period (only three stations show significant trends). The maximum seasonality index is observed after 1990 in most stations. However, the trends of seasonal rainfall anomalies for all four seasons in the northwest parts of Iran are negative, but in the central and western regions changes in anomaly trends are positive. This means that seasonal rainfall year to year variations are reduced in the northwest of the country. Highest number of significant trends is observed in winter precipitation. Manuscript profile -
Open Access Article
110 - Application of Caspian Sea SST and SLP data for studying drought in Mazandaran Province
M. Abediny H. Askary Shirazi A. RanjbarIn this research, application of seasurface temperature, sea surface pressureandprecipitationin theprovince ofMazandaranwasstudied. Meanmonthlyseasurfacetemperaturedatain30-yearperiodwas obtainedfrom NOAA. Thirty-yearaveragemonthlyprecipitationdata was taken frommeteoro MoreIn this research, application of seasurface temperature, sea surface pressureandprecipitationin theprovince ofMazandaranwasstudied. Meanmonthlyseasurfacetemperaturedatain30-yearperiodwas obtainedfrom NOAA. Thirty-yearaveragemonthlyprecipitationdata was taken frommeteorologicaloffice of Mazandaran provinceforBabolsar, Qharakhyl,Noshahrand Ramsar stations. The correlation betweenseasurfacetemperaturesand rainfallindifferent months inthe provincewas calculated. Ineachmonth,the thirddegreeregressionlinewasusedforstatisticalestimation. In thepresent study it wasshownthat there is negative correlation,with 95 percent confidence interval,betweensea surface temperatureof Caspian Seaagainstprecipitation and standardizedprecipitationindex inthe inMazandaran Province. It can be deducedthat decreasing sea surface temperature at different months of the year decreases precipitationand rising seasurfacetemperature increases rainfall. Sea surface pressure study also showed that increase in SSP increases rainfall and decrease in SSP increases drought in Mazandaran province. Manuscript profile -
Open Access Article
111 - Study of effect of NAO Index on temperature and precipitation of southern coastal region of Caspian Sea in 1977-2009 periods
S. Tabarestani A. AsgariThe North Atlantic oscillation (NAO) is one of the effective indices in changing atmospheric situation of northern hemisphere .Southern coastal region of Caspian Sea is affected by different atmospheric systems and teleconnections such as NAO because of its special geog MoreThe North Atlantic oscillation (NAO) is one of the effective indices in changing atmospheric situation of northern hemisphere .Southern coastal region of Caspian Sea is affected by different atmospheric systems and teleconnections such as NAO because of its special geographical situation. In this research, precipitation and temperature data of southern coastal region of Caspian Sea are examined for 8 synoptic stations in 1977-2009 period. NAO index data are also received from cpc.noaa.gov website. Precipitation and temperature data were examined with their corresponding NAO indices data by correlation test in monthly and yearly time scales. Furthermore, we found that in this region, when NAO index increases, precipitation will increase and temperature will decrease and vice versa. During recent years, NAO index shows negative trend, so we expect decrease of precipitation and increase of temperature in the region. Manuscript profile -
Open Access Article
112 - Evaluation of precipitation forecasts of WRF model for daily heavy rain in Qazvin Province during 2002-2011
F. Arkian N. Mashatan P. S. Katiraie Borojerdi E. Mirzaei Haji BaghloIn this study, the precipitation forecasts by WRF model for daily pervasive heavy rains in Qazvin province was evaluated. For this purpose, 30 cases of the heavy and pervasive rains in Qazvin province during (2002-2011) with two different configurations (KFMYJ, GDMYJ) s MoreIn this study, the precipitation forecasts by WRF model for daily pervasive heavy rains in Qazvin province was evaluated. For this purpose, 30 cases of the heavy and pervasive rains in Qazvin province during (2002-2011) with two different configurations (KFMYJ, GDMYJ) schemes by the WRF model at intervals of 24, 48 and 72 hours, have been simulated. Because of various heights and different climates of Qazvin and considering average rainfall, Qazvin was divided into five precipitation regions containing plain, plain margins, submontane, and mountains of Northeast and Southwest. Then with the two methods, point and areal, simulated rainfall and the corresponding observed values were evaluated. According to evaluated results, for GDMYJ configuration, root mean square error and bias multiple, with respective values of about 8.7 and 1.7 for 24-hour rainfall simulation are better than 48 and 72 hours. Also correlation coefficient between observations and model simulations of precipitation in the submontane region in comparison with other regions has slightly higher accuracy of approximately 0.5. In general, the fraction of systematic error to total error is very low and it is more due to random errors. Considering the rainfall threshold ≥10 mm and the 2×2 contingency tables for the occurrence or absence of precipitation, skill scores were calculated for the model in Qazvin region. The results showed that the model skill in predicting precipitation in 24, 48 and 72 hours on the threshold has acceptable accuracy and on average about 71% of cases were correctly predicted. Manuscript profile -
Open Access Article
113 - The effect of various parameters on the Jarosite formation in bioleaching of Sarcheshmeh copper mine sulfide ores
Bahman Nazari Hadi Hani Esmaeil Jorjani Zahra ManafiAbstract: Background and Objective: Jarosite is one of the limiting factors for recovery of copper from copper sulfide minerals. This study aimed to evaluate the influence of concentration of ferrous sulfate, pH and temperature on the jarosite formation during the sulf MoreAbstract: Background and Objective: Jarosite is one of the limiting factors for recovery of copper from copper sulfide minerals. This study aimed to evaluate the influence of concentration of ferrous sulfate, pH and temperature on the jarosite formation during the sulfide ore bioleaching of Sarcheshmeh copper mine. Material and Methods: In this study, samples were collected from the depot crushing heap bioleaching site of Sarcheshmeh Copper Mine. The bioleaching experiments were performed in 500 ml flasks, containing 10% solids of sulfide ore (w/v), pulp (200 ml), the 9K culture medium, bacteriainoculation (10% v/v of Acidithiobacillus ferrooxidans). The flask were shaked at 130 rpm throughout incubation. Results: Our results showed that increase in pH and concentration of ferrous sulfate facilitate rate of ferric iron precipitation. Maximum precipitation rate of ferric was achieved in 50 g/l of sulfate concentration, temperature 32 ° C and pH 2/2. According to XRD and FTIR analysis of Bioleaching residue, the produced ferric precipitations are often potassium and ammonium jarosite. Conclusion: With regard to the optimal conditions in this study in terms of pH, temperature and concentration of ferrous sulfate it is possible to regulate Jarosite formation through bioleaching process and to increase the production of copper efficiency from copper sulfide ores. Manuscript profile -
Open Access Article
114 - Victimization of women in the national and transnational realm with emphasis on criminological theories
Mahdiyeh Vejdani fakhr Shahrdad Darabi Ali Najafi TavanaField and Aims: From the second half of the twentieth century, criminologists changed their views on crime and considered crime as something beyond the offender, and in this regard, the victim was also considered. The purpose of this study is to explain the victimizatio MoreField and Aims: From the second half of the twentieth century, criminologists changed their views on crime and considered crime as something beyond the offender, and in this regard, the victim was also considered. The purpose of this study is to explain the victimization of women with emphasis on criminological and victimological theories. And theories of rational choice, routin activities and lifestyle are known as theories of crime opportunities, and the theory of victim precipitation is defined as the victimilogical theory. In this article, these theories are used as the most important basis for victimization of women.Method: The present research was carried out using a descriptive-analytical method.Finding and Conclusion: According to the theory of victim precipitation, the victim has a role in the process of committing criminal behavior, and according to this role, the victim deserves blame, and the victim's actions, such as age, gender, are the primary characteristics that can make her a target for crime. her position in situations that make it difficult for her to make optimal decision.. But regardless of their role as provocateurs or facilitators or lifestyles, women deserve differential support because of their vulnerability characteristics. And opportunity theories, in addition to acknowledging that crime opportunities can belong to different domains, claim that opportunity factors interact in different domains. Manuscript profile -
Open Access Article
115 - Water- Balance and Agro- climatic Analysis in Shiraz Region, By Thornthwaite's methods
Abbas Ali AbounooriDrought is a random characteristic of natural phenomena, brought about by the irregulardeficit or shortage of available water, affects injuriously the plant growth and reduces their yield. Drought does not begin when rain ceases but rather only when plant roots can no l MoreDrought is a random characteristic of natural phenomena, brought about by the irregulardeficit or shortage of available water, affects injuriously the plant growth and reduces their yield. Drought does not begin when rain ceases but rather only when plant roots can no longer obtain soil moisture in needed amounts. To estimate the intensity and the frequency of droughts will help to reduce the injurious effect of drought. In this Study we used the water- budget methods and Thornthwaite's aridity index and its standard deviation for Shiraz during 88<8-9228 to show the frequency and the intensity of drought effects in this place. During this period this station is faced :< times different type of droughts on that five time severe and from the years of 9222 its severity and intensity is increased. We also find out that every ten year this station will affect : times severe type of drought. The most severe drought was the years 9228,and it was repeated lower intensity in the year of 9221 Manuscript profile -
Open Access Article
116 - Ecological Effects of Climate Factors on Rangeland Vegetation (Case Study: Polour Rangelands)
Diana Askarizadeh Hossein Arzani -
Open Access Article
117 - Investigating the Fluctuations of Precipitation on Rangeland Vegetation Yield and Cover in Steppic Rangelands (Case study: Sadrabad Rangelands of Nadoushan-Yazd province-Iran)
hadi farokhi Saeid Mohtashamnia Majid AbbasizadehInvestigating rangeland vegetation cover and yield changes in relation to precipitation fluctuations is considered as an important factor which can be affected on range ecosystem analysis, grazing management, rehabilitation and reclamation programs. In this research, th MoreInvestigating rangeland vegetation cover and yield changes in relation to precipitation fluctuations is considered as an important factor which can be affected on range ecosystem analysis, grazing management, rehabilitation and reclamation programs. In this research, the precipitation fluctuations on rangeland vegetation cover and yield of steppic rangelands was considered in Nadoushan-Yazd province. For investigating cover and precipitation effect, three main species were selected and measured. Based on palatability, yield has been measured in random plots. Finally, statistical analysis was conducted by using stepwis regression techniques. Results showed the most dominant species reacted to precipitation fluctuations. Erotia ceratoides cover showed positive regression with recent precipitation whereas Stipa barbata and Artemisia sieberi cover had related with January to March precipitation. Basically, precipitation has the most effect on whole vegetation particularly class III plants and growth season besides winter season caused production in class II and I respectively. Manuscript profile -
Open Access Article
118 - Synthesis of ZnWO4 nanoparticles and manufacturing scintillator for detecting Gama- rays
رسول صراف ماموری آرزو عبدالرحمانی خیراله محمدی محسن روشنIn this study, ZnWO4 nanoparticles were synthesized through co-precipitation method with sodium tungstate dehydrate (Na2WO4.2H2O) and zinc nitrate hexahydrate (Zn (NO3)2.6H2O) as starting materials. In order to optimize the conditions for obtaining smallest mean particl MoreIn this study, ZnWO4 nanoparticles were synthesized through co-precipitation method with sodium tungstate dehydrate (Na2WO4.2H2O) and zinc nitrate hexahydrate (Zn (NO3)2.6H2O) as starting materials. In order to optimize the conditions for obtaining smallest mean particle size, Central Composite Design (CCD) was used and three parameters of temperature, weight ratio of precursors, and pH value were studied in five levels. The obtained ZnWO4 nanoparticles were characterized by Field Emission Scanning Electron Microscopy (FE-SEM), powder x-ray diffraction (XRD), thermal gravimetric- differential scanning calorimetry (TG-DSC) and photoluminescence (PL). The results showed that optimal conditions for smallest mean nanoparticles with particle size of 37.3 6.9 nm were temperature =83 , weight ratio of precursor equal to 1.1, and pH=6. The resulting ZnWO4 nanoparticles were dry- pressed to green compact pellets with a diameter of 11mm and thickness of 1.5 nm at the compaction pressure of 500 MPa. The densification of nanoparticles compacts was carried out by a pressure less sintering at 950 for 2 hours in air atmosphere. Scintillation properties of pellets were determined by means of Gama-rays spectroscopy. The results showed that manufactured ZnWO4 pellets illustrated counting sensitivity to Cs137 and Am241 irradiation sources and couldn’t detect energy of Gama-rays emitted from this two source. Manuscript profile -
Open Access Article
119 - The effect of temperature and time of calcination on synthesis of YAG nano-crystalline by normal co-precipitation method
امید میرزایی mahsa rahmani mohammad tajallyNano-crystalline Yttrium aluminum garnet (YAG, Y3Al5O12) were synthesized by normal co-precipitation method using yttria and aluminum nitrates as the starting materials and ammonium hydrogen carbonate (AHC, NH4HCO3) as precipitant. To investigate the effect of temperatu MoreNano-crystalline Yttrium aluminum garnet (YAG, Y3Al5O12) were synthesized by normal co-precipitation method using yttria and aluminum nitrates as the starting materials and ammonium hydrogen carbonate (AHC, NH4HCO3) as precipitant. To investigate the effect of temperature and holding time the resultant precursors were calcined at 900-1100 °C for 2 h also at 1100 °C for other durations (15, 30, 45 and 60 min). The evolution of phase composition and micro-structure of the as-synthesized YAG powders were characterized by different techniques such as X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermal analyses (TG/DTA), Specific surface area analyses (BET) and field emission electron microscopy (FESEM). The cubic YAG phase with an average grain size of 33 nm and specific surface area of 30 m2/g was completely formed at 1000 °C. In addition, pure YAG nano powders were obtained at 1100 °C in only 15 min calcination. Results showed that compared with increasing holding time, raising of temperature have more intense effect in increasing YAG crystal or particle size. Manuscript profile -
Open Access Article
120 - An investigation on the behavior of manganese cobaltite spinel oxide as the SOFC interconnect coating materials
Pooria Lesani Alireza Babaei Abolghasem AtaieIn this study, Manganese cobaltite (MnCo2O4) spinel powders were synthesized by co-precipitation method. X ray diffraction (XRD) patterns show that the spinel phase was formed at around 350°C. Formation of spinel phase was further completed by increasing temperature MoreIn this study, Manganese cobaltite (MnCo2O4) spinel powders were synthesized by co-precipitation method. X ray diffraction (XRD) patterns show that the spinel phase was formed at around 350°C. Formation of spinel phase was further completed by increasing temperature up to 1000°C. Additionally, XRD patterns prove that MnCo2O4 spinel material has been stable in this temperature range. Field emission scanning electron microscope observations show that plate like particles with an average diameter of 148 and thickness of 18 nm was converted to equiaxed particles with an average particle size of 1.5 µm by increasing calcination temperature from 350 to 1000°C. Investigation of the coating of uncalcined and calcined powder on AISI 430 ferritic stainless steel shows that a proper dense coating is developed on the stainless steel surface by using uncalcined precursor powders. And also, this coating performs well by prohibiting of outward diffusion of Fe from the substrate. In this way, a low thickness chromia layer (Cr2O3) is formed between the coating and the substrate. EDX analysis shows that a mixed spinel zone is formed in the interface of the coating and the substrate due to diffusion of some elements such as Mn, Cr, and Fe from substrate to the coating, as well as Mn and Co from coating to the substrate. Manuscript profile -
Open Access Article
121 - Precipitation synthesis and luminescence properties of MgAl2O4 nanoparticles doped with samarium
مژده ملک پور جرقویه سید علی حسن زاده تبریزی علی صفارA surfactant assisted Co-Precipitation method was employed for the synthesis of magnesium aluminate spinel with nanocrystalline size and high specific surface area. Calcination operations were performed in 800-1000° C for two hours. Different percentages of samarium MoreA surfactant assisted Co-Precipitation method was employed for the synthesis of magnesium aluminate spinel with nanocrystalline size and high specific surface area. Calcination operations were performed in 800-1000° C for two hours. Different percentages of samarium were doped to magnesium aluminate spinel to examine the properties of magnesium aluminate spinel. The prepared samples were characterized by thermal gravimetric and differential thermal gravimetric analyses (TG/DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Transmission electron microscopy (TEM), and photoluminescence spectrum (PL). XRD results showed that nanocrystals of magnesium aluminate spinel were influenced by the type of surfactant in 800° C. The results of luminescence spectrum show that by increasing the amount of samarium after 0.15 of weight percentage, concentration suppression happens and reduces the intensity of luminescence properties. Manuscript profile -
Open Access Article
122 - Synthesis of Cadmium Doped Nickel Copper Ferrite Nanoparticles and Investigation of Their Sensing Properties for the Detection of Acetonitrile in Little Accounts
Hossein Emami Hamid Reza EbrahimiIn this study cadmium doped nickel copper ferrite Ni0.5Cu0.5Fe2O4 (cd doped) nanoparticles with spinel structure were synthesized using co-precipitation method. The nanoparticles were employed as a gas sensing material. X-ray diffraction (XRD), X-ray fluorescence (XRF) MoreIn this study cadmium doped nickel copper ferrite Ni0.5Cu0.5Fe2O4 (cd doped) nanoparticles with spinel structure were synthesized using co-precipitation method. The nanoparticles were employed as a gas sensing material. X-ray diffraction (XRD), X-ray fluorescence (XRF) and transmission electron microscopy (TEM) techniques were used to characterize the nanoparticles structure. The sensing behavior of the nanoparticles was examined in the presence of different gases including. Acetone, acetonitrile, acrylonitrile, formamide, caron tetrachloride, vinyl acetate, ethanol, ammonia, and methanol. The characterization process was performed for a concentration of a 200 ppm and within a temperature interval from 50 ˚C to 300 ˚C and the best sensing behavior was found to be at 200 ˚C. Furthermore, various concentrations of acetonitrile gas at 200 ˚C within a concentration interval of 20 to 200 ppm were tested and it is found that the higher concentrations will result in a better response. Manuscript profile -
Open Access Article
123 - Synthesis of Zinc Ferrite Ferrofluid and Investigation of its Rheology and Magnetic Properties
Farshid Mahdavi Babak HashemiIn this study, we first synthesized zinc ferrite nanoparticles by using co-precipitation method and adding zinc to iron ferrite in different amounts. Redistribution of Fe and Zn cations in tetrahedral and octahedral locations can significantly alter and increase saturat MoreIn this study, we first synthesized zinc ferrite nanoparticles by using co-precipitation method and adding zinc to iron ferrite in different amounts. Redistribution of Fe and Zn cations in tetrahedral and octahedral locations can significantly alter and increase saturation magnetization. The saturation magnetization of the synthesized ferrite nanoparticles was 57% higher than that of iron ferrite, and the nanoparticles had an average size of 35 nm. The synthesized nanoparticles were then functionalized using oleic acid and polyethylene glycol and three types of stable fluids based on water, engine oil and ethylene glycol were prepared. Optimal Ferro-fluid with the highest stability properties and amount of saturated magnetization was used to investigate the rheological properties. The non-Newtonian behavior of the fluid with different percentages of nanoparticles was investigated and the greatest change in behavior from the Newtonian state was related to the fluid with 15% by volume of nanoparticles. Manuscript profile -
Open Access Article
124 - Modeling of aging process for pre-rolled Ni-Span C 902 superalloy
Mohammad Rasool Moazami Godarzi Maryam Morakabati Seyed Mahdi Abbasi Hassan BadriThe age-hardening curves of hardness measurements obtained for Ni-Span C 902 superalloy under different amounts of cold work, aging temperatures and times showed leveling and pronounced oscillations, indicating instability and reflecting a competition between the effect MoreThe age-hardening curves of hardness measurements obtained for Ni-Span C 902 superalloy under different amounts of cold work, aging temperatures and times showed leveling and pronounced oscillations, indicating instability and reflecting a competition between the effect of sub-structure coarsening and the effect of solute drag and precipitation hardening. An artificial neural network (ANN) was used to model the nonlinear relationship between the parameters of the aging process and the corresponding hardness measurements. The predicted values of the ANN are in accordance with the experimental data. Results showed that the non-deformed and 50 pct cold rolled alloy exhibited a maximum hardness at a tempering parameter of 22 and 21, respectively. Manuscript profile -
Open Access Article
125 - Fabrication of NO2 gas sensor structure based on ZnMn2O4 nanoparticles
Mahsa Mojiri Andani Parviz Kameli Saeid Salari Mehdi RanjbarNO2 as a toxic gas in the environment and industry, is abundantly produced and needs to be detected. In this research, the measurement of NO2 gas using ZnMn2O4 nanoparticles made through a simple co-precipitation, process has been investigated. The structure and surface MoreNO2 as a toxic gas in the environment and industry, is abundantly produced and needs to be detected. In this research, the measurement of NO2 gas using ZnMn2O4 nanoparticles made through a simple co-precipitation, process has been investigated. The structure and surface morphology of the prepared samples have been analyzed by X-ray diffraction and scanning electron microscopy, respectively. The X-ray diffraction spectrum shows that the structure of the sample is well formed without impurities. Electron microscope images show that the nanoparticles are formed as nanoplates with an average thickness of 30 nm. Gas sensing measurements were performed by exposing the sensor to %0.5 of NO2 gas at temperatures between 150 ℃ and 375 ℃. The measurements made in terms of temperature showed the maximum response at the temperature of 300 ℃, to %0.5 of NO2 gas. Also, the ZnMn2O4 sensor showed a repeatable and stable electrical signal. Therefore, ZnMn2O4 nanoparticles have a promising potential in the field of gas sensors. Manuscript profile -
Open Access Article
126 - A Simple Polymer-based Co-Precipitation Method for Tuning Magnetic Properties of Cobalt-Doped Nickel Ferrite Nanoparticles
Sharareh MirzaeeIon distribution on the spinel structure of ferrite nanoparticles is one of the critical factors that can affect magnetic properties. Therefore, if a method changes ion distribution, it can be used for fabrication (synthesis) of nanoparticles with different magnetic p MoreIon distribution on the spinel structure of ferrite nanoparticles is one of the critical factors that can affect magnetic properties. Therefore, if a method changes ion distribution, it can be used for fabrication (synthesis) of nanoparticles with different magnetic properties that apply in the diverse of technology field. In this work, the dependence of magnetic characteristics of the cobalt-doped nickel ferrite nanoparticles on Polyvinyl alcohol (PVA) assisted co-precipitation processes was studied. The structural and magnetic measurements were made employing XRD and VSM. Nanoparticles with a cubic spinel structure and an average size of about 29 nm have been synthesized, and their structure was confirmed using the XRD pattern and Sherrer’s equation. According to the obtained hysteresis loops of the five sets of synthesized nanoparticles, the coercive field and magnetization are different because of the interaction between polymer and metal ions in the reaction medium that causes a kind of ion immobilization and different ion distribution over the spinel structure. Such polymer-based synthesis procedures can be used to fabricate of magnetic nanoparticles with tunable magnetic properties. Manuscript profile
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