پديد آورندگان :
خاني تمليه، ذبيح‌اله دانشگاه اروميه , رضايي، حسين دانشگاه اروميه - گروه مهندسي آب , ميرعباسي نجف‌آبادي، رسول دانشگاه اروميه - گروه مهندسي آب
كليدواژه :
تابع مفصل , تحليل دومتغيره , دوره‌ي بازگشت , ريسك خشك‌سالي , شاخص SPImod
چكيده فارسي :
ﺧﺸﮏ ﺳﺎﻟﯽ ﻫﺎ ﭘﺪﯾﺪه ﻫﺎي ﺣﺪي ﻫﺴﺘﻨﺪ ﮐﻪ ﺑﺮ اﺳﺎس ﺧﺼﻮﺻﯿﺎت ﺗﺪاوم در زﻣﺎن و ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ اﺛﺮات ﻣﮑﺎﻧﯽ آن ﻫﺎ ﺗﻮﺻﯿﻒ ﻣﯽ ﺷﻮﻧﺪ و ﻣﯽ ﺗﻮاﻧﻨﺪ در ﻫﺮ وﺿﻌﯿﺖ اﻗﻠﯿﻤﯽ رخ دﻫﻨﺪ. ﺷﻨﺎﺧﺖ و رﻓﺘﺎر ﺧﺸﮏ ﺳﺎﻟﯽ ﻫﺎ ﮐﻪ ارﺗﺒﺎط ﺗﻨﮕﺎﺗﻨﮓ و ﺑﯽ واﺳﻄﻪ اي ﺑﺎ ﻣﺪﯾﺮﯾﺖ ﻣﻨﺎﺑﻊ آب دارد، از اﻫﻤﯿﺖ وﯾﮋه اي ﺑﺮﺧﻮردار اﺳﺖ. ﻫﺪف اﺻﻠﯽ اﯾﻦ ﻣﻄﺎﻟﻌﻪ، ارزﯾﺎﺑﯽ رﯾﺴﮏ ﺧﺸﮏ ﺳﺎﻟﯽ ﺑﺎ اﺳﺘﻔﺎده از ﺗﻮاﺑﻊ ﻣﻔﺼﻞ، در ﺗﺤﻠﯿﻞ دوﻣﺘﻐﯿﺮه ﭘﺪﯾﺪه ي ﺧﺸﮏ ﺳﺎﻟﯽ در ﺷﺮق ﮐﺸﻮر اﺳﺖ. ﺑﺪﯾﻦ ﻣﻨﻈﻮر، اﺑﺘﺪا ﺑﺎ اﺳﺘﻔﺎده از ﺷﺎﺧﺺ ﺑﺎرش اﺳﺘﺎﻧﺪاردﺷﺪه ي اﺻﻼﺣﯽ )SPImod( ﺧﺼﻮﺻﯿﺎت ﺧﺸﮏ ﺳﺎﻟﯽ ﺷﺎﻣﻞ ﺷﺪت و ﻣﺪت اﺳﺘﺨﺮاج ﮔﺮدﯾﺪ. در اداﻣﻪ ﺟﻬﺖ ارزﯾﺎﺑﯽ رﯾﺴﮏ ﺧﺸﮏ ﺳﺎﻟﯽ و ﺗﺤﻠﯿﻞ دوﻣﺘﻐﯿﺮه ي آن، ﻋﻤﻠﮑﺮد 9 ﺗﺎﺑﻊ ﻣﻔﺼﻞ ﮐﻼﯾﺘﻮن، ﻋﻠﯽ-ﻣﯿﺨﺎﺋﯿﻞ-ﺣﻖ، ﻓﺎرﻟﯽ-ﮔﺎﻣﺒﻞ-ﻣﻮرﮔﻨﺴﺘﺮن، ﻓﺮاﻧﮏ، ﮔﺎﻣﺒﻞ، ﮔﺎﻣﺒﻞ-ﻫﻮﮔﺎرد، ﭘﻼﮐﺖ، ﻓﯿﻠﯿﭗ-ﮔﺎﻣﺒﻞ و ﺟﻮﺋﯽ ﺑﺮازش ﺑﺮ داده ﻫﺎي ﺷﺪت و ﻣﺪت ﺧﺸﮏ ﺳﺎﻟﯽ ﻣﻮرد آزﻣﻮن ﻗﺮار ﮔﺮﻓﺖ. ﺟﻬﺖ ﺗﺸﺨﯿﺺ ﺗﺎﺑﻊ ﻣﻔﺼﻞ ﺑﺮﺗﺮ از ﻣﻌﯿﺎرﻫﺎي آﮐﺎﺋﯿﮑﻪ، ﺣﺪاﮐﺜﺮ درﺳﺖ ﻧﻤﺎﯾﯽ و ﺿﺮﯾﺐ ﻧﺶ-ﺳﺎﺗﮑﻠﯿﻒ اﺳﺘﻔﺎده ﮔﺮدﯾﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﺗﻮاﺑﻊ ﺗﻮزﯾﻊ ﮔﺎﻣﺎ و ﻧﻤﺎﯾﯽ ﺑﻪﻋﻨﻮان ﺗﻮاﺑﻊ ﺗﻮزﯾﻊ ﺣﺎﺷﯿﻪ اي ﺑﺮﺗﺮ ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﺮاي ﻣﺘﻐﯿﺮﻫﺎي ﺷﺪت و ﻣﺪت ﺧﺸﮏ ﺳﺎﻟﯽ ﺷﻨﺎﺳﺎﯾﯽ ﺷﺪﻧﺪ و ﺿﺮﯾﺐ ﻧﺶ-ﺳﺎﺗﮑﻠﯿﻒ در ﻣﺤﺪوده ي 0/76 ﺗﺎ 0/99، ﻣﯿﺎﻧﮕﯿﻦ ﻣﺮﺑﻌﺎت ﺧﻄﺎ در ﻣﺤﺪوده ي 0/007 ﺗﺎ 0/034، ﺟﻬﺖ ﺗﻌﯿﯿﻦ ﺗﺎﺑﻊ ﻣﻔﺼﻞ ﺑﺮﺗﺮ ﺑﻪ دﺳﺖ آﻣﺪ ﮐﻪ ﺗﺎﺑﻊ ﻣﻔﺼﻞ ﺟﻮﺋﯽ ﺗﺎﺑﻊ ﺑﺮﺗﺮ ﺑﺮاي اﯾﺠﺎد ﺗﻮزﯾﻊ دوﻣﺘﻐﯿﺮه در ﻣﻨﻄﻘﻪ ي ﻣﻮردﻣﻄﺎﻟﻌﻪ ﺷﻨﺎﺧﺘﻪ ﺷﺪ. ﻫﻤﭽﻨﯿﻦ ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از ارزﯾﺎﺑﯽ رﯾﺴﮏ ﺧﺸﮏ ﺳﺎﻟﯽ ﺑﺎ اﺳﺘﻔﺎده از دوره ي ﺑﺎزﮔﺸﺖ ﺗﻮأم ﻧﺸﺎن داد ﮐﻪ ﺑﯿﺶ ﺗﺮﯾﻦ ﺧﻄﺮ رﯾﺴﮏ ﻣﺮﺑﻮط ﺑﻪ اﯾﺴﺘﮕﺎه ﻫﺎي ﺑﺠﻨﻮرد، ﺳﺒﺰوار، ﺗﺮﺑﺖ ﺣﯿﺪرﯾﻪ و ﻣﺸﻬﺪ اﺳﺖ؛ ﺑﻪ ﻃﻮري ﮐﻪ در اﯾﺴﺘﮕﺎه ﺳﺒﺰوار ﺣﺪود 53 درﺻﺪ از ﮐﻞ ﻣﺎه ﻫﺎ در ﻃﯽ دوره ي آﻣﺎري ﺧﺸﮏ ﺑﻮده اﺳﺖ و ﺑﺮاي اﯾﺴﺘﮕﺎه ﺑﺠﻨﻮرد ﺣﺪود 55 درﺻﺪ اﺳﺖ. ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از ﺗﺤﻠﯿﻞ رﯾﺴﮏ ﺑﺮ ﻣﺒﻨﺎي دوره ي ﺑﺎزﮔﺸﺖ و ﺗﻮاﺑﻊ ﻣﻔﺼﻞ ﻣﯽ ﺗﻮاﻧﺪ اﻃﻼﻋﺎت ﻣﻔﯿﺪي را در اﺧﺘﯿﺎر ﺑﺮﻧﺎﻣﻪ رﯾﺰان ﻣﻨﺎﺑﻊ آب، ﻣﺴﺎﺋﻞ زﯾﺴﺖ ﻣﺤﯿﻄﯽ، ﮐﺸﺎورزان ﻗﺮار دﻫﺪ.
چكيده لاتين :
Droughts are extreme phenomena that are described based on the characteristics of continuity in time and according to their spatial effects and can occur in any climatic situation. Recognition and behavior of droughts, which are closely and directly related to water resources management, are of particular importance. The main purpose of this study is to assess the risk of drought using Copula functions in the bivariate analysis of drought in the east of the country. For this purpose, drought characteristics including intensity and duration were extracted using modify standardized precipitation index (SPImod). To assess the risk of drought and analyze its two variables, the performance of nine copula functions of Clayton, Ali-Michael-Haq, Farli-Gumble-Morgenstern, Frank, Gumble, Gumble-Hoggard, Plackett, Filip-Gumble and Joe fits the intensity data and Drought duration was tested. Akaike criteria, maximum likelihood, and Nash-Sutcliffe coefficient were used to identify the superior joint function. The results showed that gamma and exponential distribution functions were identified as superior margin distribution functions for the variables of intensity and duration of drought, respectively, and the Nash-Sutcliffe coefficient ranged from 0.76 to 0.99, and the mean square error ranged from 0.007 to0 034., to determine the superior copula function, it was obtained that the copula function of the superior function was known to create a bivariate distribution in the study area. Also, the results of drought risk assessment using the joint return period showed that the highest risk is related to Bojnourd, Sabzevar, Torbat Heydariyeh, and Mashhad stations, so that Sabzevar station was dry about 53% of the total months during the statistical period and for Bojnourd station is about 55%. The results of risk analysis based on return period and copula functions can provide useful information to planners of water resources, environmental issues, farmers.
