List of Articles Standard precipitation index

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  1 - 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 BazErafshan
  Drought 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 More

  Drought 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
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  2 - 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 Pormanafi
  Land 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- More

  Land 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
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  3 - Evaluation of indices based on remote sensing in drought monitoring of Neyriz city
  Mohammad Shabani
  10.30495/girs.2022.690925
  Background 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 More

  Background 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
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  4 - 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 معروفی
  خشک 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 More

  خشک 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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  5 - 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 afifi
  In 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, More

  In 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
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  6 - Drought effects on surface water quality in Golestan province for Irrigation Purposes, Case study: Gorganroud River
  Nader Jandaghi Ali Heshmatpour Mojtaba Ghareh Mahmoodlu Saeedeh Pasand
  In 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 More

  In 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
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  7 - Assessment of the Vegetation Dryness Index Based on Satellite Imagery in Sistan & Balouchestan province
  kamal omidvar Masoumeh NabaviZadeh Hamid Reza Ghafarian malmiri Ahmad Mazidi
  Decreasing 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 More

  Decreasing 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