List of Articles Return Period

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  1 - Frequency analysis of floods with joint functions, case study: Zayandehrood Dam
  Fatemeh Valaei Esfahani Zahra  Valaei Esfahani Mehran Iranpour
  Analyzing the frequency of floods and knowing the probability of occurrence and return period of this phenomenon is important in how to exploit the reservoir. This phenomenon is inherently multivariate and the use of classical multivariate functions to analyze this phen More

  Analyzing the frequency of floods and knowing the probability of occurrence and return period of this phenomenon is important in how to exploit the reservoir. This phenomenon is inherently multivariate and the use of classical multivariate functions to analyze this phenomenon is limited. Therefore, it is recommended to use copula functions for multivariate flood frequency analysis. These functions combine the distribution function of the univariate distribution function by considering the type of correlation of the variables. For frequency of this phenomenon, the variables of peak discharge, volume and duration of flood are used. This study was conducted on statistical data of Zayandehrood dam. Based on goodness of fit criteria, the best function is fitted to the each of the variables. The correlation of each pair of variables is calculated and the copula function is selected based on the Akaike, NSE, and RMSE criteria. After that, the obtained univariate and combined return periods have been displayed. These results can be used to estimate the risk. Manuscript profile
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  2 - Estimation of the probability of occurrence of heat waves with different periods of continuation in Ardabil province
  batool zeynali fatemeh rouhi
  10.30495/sarzamin.2023.71948.2086
  Heatwaves are one of the natural and intrinsic phenomena of the climate in different parts of the world whose frequency of occurrence as a result of global fluctuations in climate over recent years is similar to other climatic phenomena. Rising air temperatures due to p More

  Heatwaves are one of the natural and intrinsic phenomena of the climate in different parts of the world whose frequency of occurrence as a result of global fluctuations in climate over recent years is similar to other climatic phenomena. Rising air temperatures due to periodic droughts or because of heating The world is very likely in the coming years .To evaluate the temperature in Ardebil province data on the maximum daily temperature of the stations of Ardebil Parsabad Khalkhal and Meshkinshahr for the years 1991 to 2016 were obtained from Ardebil's meteorological conditions. In this study in order to study the heating periods in different months of Ardebil province also to illustrate the changes The period of continuity and the return period of heat waves have been identified and the Markov chain has been usedAccordingly in no fish the waves are the most frequent and the short and long wave were the highest in April and the lowest in September.Using these tables of the period of continuity and the calculated return period of the heat wave during the warm year the level of stations in the province of Ardabil we find that in April May and June Parsabad station has the least heat recovery period and the months of July August And in September Ardebil station has the shortest period of return. The most frequent return periods were observed in April May June July and August at Meshkinshahr Station and observed in Khalkhal Station in September.Also, the existence of Azores dynamic high pressure in Iran has caused a strong heat rule in our study area. Manuscript profile
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  3 - 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 Mirabbasi
  10.30495/wsrcj.2022.19226
  Background 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 More

  Background 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
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  4 - 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 Mirabbasi
  Drought 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 More

  Drought 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
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  5 - برآورد دبی سیلاب طراحی برای مطالعات ساماندهی رودخانه سرخه‌حصار (محدوده شهرک ولی عصر شهر ری)
  مجید عبادی فر سید علی حسینی ابری امین عبادی فر مهدی شمس آبادی زاده
  اصلاح و به‎سازی مسیر رودخانه­ها بر خصوصیات سیلاب از قبیل پهنه سیل، شکل هیدروگراف و سرعت جریان در مقاطع مختلف تأثیرگذار است و برای آن که بتوان این اقدامات را به بهترین شکل ممکن به انجام رساند، نیاز به برآورد صحیح دبی سیلاب با دوره بازگشت­های مختلف م More

  اصلاح و به‎سازی مسیر رودخانه­ها بر خصوصیات سیلاب از قبیل پهنه سیل، شکل هیدروگراف و سرعت جریان در مقاطع مختلف تأثیرگذار است و برای آن که بتوان این اقدامات را به بهترین شکل ممکن به انجام رساند، نیاز به برآورد صحیح دبی سیلاب با دوره بازگشت­های مختلف می­باشد. تحقیق حاضر با هدف تعیین ابعاد سیلاب طراحی رودخانه سرخه­حصار در محدوده شهرک ولی­عصر شهر ری نظر انجام گرفته است. برای این کار، ضمن بهره­گیری از قابلیت­های نرم­افزار Hyfran-plus، از روش منطقه­­ای (با انتخاب 16 ایستگاه هیدرومتری) و همچنین روش­های دبی ویژه سیلاب و نسبت دوره ­بازگشت (با انتخاب ایستگاه تقی­آباد به عنوان مبنا) استفاده گردید. نتایج تحقیق نشان داد که بین مقادیر دبی سیلابی محاسبه شده از روش­های مختلف اختلاف فاحشی وجود دارد که علت این امر را می‌توان به شرایط خاص حوضه آبریز رودخانه مورد مطالعه و برخورداری از کمترین توان تولید سیلاب در مقایسه با حوضه­های اطراف آن نسبت داد. اگرچه به نظر می­رسد که استفاده از دبی ویژه سیلاب ایستگاه مبنا نتایج منطقی­تری نسبت به روش منطقه­­ای بدست می­دهد، اما بررسی­های میدانی نشان داد که «نسبت دوره ­بازگشت در ایستگاه مبنا»، از مقبولیت بیشتری نسبت به سایر روش­ها برخوردار بوده و بر این اساس، دبی پیک سیلاب رودخانه با دوره بازگشت­های 25، 50 و 100 سال، به ترتیب برابر 118، 128 و 137 مترمکعب در ثانیه بدست می­آید. در نهایت، جهت تهیه ابعاد هیدروگراف سیلاب طراحی، با توجه به عدم دسترسی به سیلاب­های ساعتی مشاهده­ای در ایستگاه مبنا، از روش تجربی SCS استفاده گردید. Manuscript profile
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  6 - Prediction Probable Flood and Maximum precipitation Using Poldukhtar Basin Suffered partial Series
  مهدی Mehdinasab تقی Tavoosi رضا Mirzaei
  Floods are natural phenomenon that human societies have accepted it as an inevitable event but the event size and frequency of flooding is caused by several factors That is, depending on climatic conditions, natural and geographical each region changes. Annually in diff More

  Floods are natural phenomenon that human societies have accepted it as an inevitable event but the event size and frequency of flooding is caused by several factors That is, depending on climatic conditions, natural and geographical each region changes. Annually in different parts of the world, many people's lives and properties due to flood risk falls And millions of tons of precious soil are destroyed by floods. One of the world is a flood natural disaster losses Bartryn. Statistical analysis has shown that about 70 percent of flood damage is caused by natural disaster in Iran This study estimated the a probable flood and maximum precipitation using Poldukhtar suffered minor series is action. The number 20 Heavy rainfall 24Hours over 40 millimeters The number  30 seals with more than 500 cubic meters per second was chosen discharge. Selection criteria for floods had chosen the first seal is attached to the previous flood. Thus, the interval between Two flood peaks from each other, must be at least 3 times the amount of time discharge began to reach the stage of the flood hydrograph peak flow needs. Secondly, the amount of discharge after the first flood and before the second flood in less than one third flood peak is reached first.The series detailed method to estimated the flood discharge and The maximum sustained 24-hour rainfall return periods of 2, 5, 10, 25, 50, 100 and 200 years has been And the results showed that each year, probably 99.99 percent slapped with a flow rate 606.32 cubic meters and a 24-hour precipitation amount of 43.07 millimeters Poldukhtar happening in theBasin Manuscript profile
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  7 - Estimation of Krieger Regional Coefficient in Mountainous Areas
  rohoullah mohtashamzadeh sajad mashali Bfhrooz Dahanzadeh
  Iran has different climatic conditions due to its climatic characteristics. These climatic differences necessitate a suitable hydrological study in each region. Lorestan province, due to its mountainousness, is more humid than other parts. Therefore, this region is more More

  Iran has different climatic conditions due to its climatic characteristics. These climatic differences necessitate a suitable hydrological study in each region. Lorestan province, due to its mountainousness, is more humid than other parts. Therefore, this region is more favorable for flood occurrence and requires specific hydrological studies. The purpose of this study is to investigate the Krieger regional coefficient in mountainous areas. Therefore, based on the latest statistics published by the provincial water company, the statistics of the maximum instantaneous flow rates of 24 hydrometric stations were obtained in different parts of the province .The area of ​​the studied watersheds varied from 9550 km2 (Kashkan Poldokhtar) to 35 km2 (small plumber). The results of this study showed that the range of Chigger coefficients in Lorestan province catchment areas is much lower than the cultivars that have been recommended so far. Also, with the increase of the return period, the Krieger coefficient increases in mountainous regions with higher trend than arid regions. This issue should be considered in the planning and management of quantitative water resources. Manuscript profile
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  8 - Estimating of seismicity parameters in Golab 2 conveyance water tunnel with preliminary Gutenberg - Richter Method
  Mohammad Azarafza Shahrzad Nikoobakht Ebrahim Asghari-Kaljahi Mirali-Akbar Nogol Sadat
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