ارزيابي تطبيقي شاخص‌هاي SPI، RDI و SDI در تحليل مشخصه‌‍‌هاي خشكسالي هواشناسي و هيدرولوژيكي (مطالعه موردي: دشت بم)

Adaptive Evaluation of SPI, RDI and SDI Indices in Analyzing the Meteorological and Hydrological Drought Characteristics (Case Study: Bam Plain

هدف از اين تحقيق تعيين سه شاخص SPI، RDI و SDI در پايش خشكسالي‌­هاي هواشناسي و هيدروﻟﻮژﯾﮑﯽ در دﺷــﺖ ﺑــﻢ و ﺑﺮرﺳــﯽ ارﺗﺒــﺎط آن ﻫــﺎ ﺑــﺎ ﯾﮑــﺪﯾﮕﺮ، ﺗﺤﻠﯿــﻞ ﻣﺸﺨﺼــﻪ ﻫــﺎي ﺧﺸﮑﺴــﺎﻟﯽ در ﻣﻘﯿــﺎسﻫــﺎي زﻣــﺎﻧﯽ ﻣﺨﺘﻠــﻒ و اﺣﺘﻤــﺎل وﻗــﻮع آنﻫﺎﺳــﺖ. ﺑﺮرﺳــﯽ ﻧﺘــﺎﯾﺞ ﺣﺎﺻــﻞ ﺑــﺎ اﺳــﺘﻔﺎده از آزﻣــﻮن t ﺟﻔــﺖ ﺷــﺪه ﻧﺸــﺎندﻫﻨــﺪه ﺗﻔــﺎوت ﻣﻌﻨــﯽدار در ﻧﺘــﺎﯾﺞ ﺷــﺪت، ﻣــﺪت و ﻓﺮاواﻧــﯽ در ﺷــﺎﺧﺺ SPI ﺑــﺎ RDI ﺑــﻮده و ﺑﯿﺸــﺘﺮﯾﻦ ﺷــﺒﺎﻫﺖ وﯾﮋﮔــﯽﻫــﺎي ﯾــﺎد ﺷــﺪه SDI ﺑــﺎ RDI ﺑــﻪدﺳــﺖ آﻣــﺪ . ﻧﺘــﺎﯾﺞ آزﻣــﻮن ﻫﻤﺒﺴــﺘﮕﯽ ﻣﺘﻘــﺎﻃﻊ ﻧﺸــﺎن دﻫﻨــﺪه ﺿــﺮاﯾﺐ ﺑــﺎﻻي ﻫﻤﺒﺴــﺘﮕﯽ ﺑـــﻪﺻـــﻮرت ﻫـــﻢزﻣـــﺎن در ﻣﻘﯿـــﺎس زﻣـــﺎﻧﯽ 48 ﻣﺎﻫـــﻪ ﺑـــﻮده ﮐـــﻪ 48-SDI-48:RDI-48 ،SPI-48:RDI و 48-SPI-48:SDI ﺑــﻪﺗﺮﺗﯿــﺐ داراي ﺿــﺮاﯾﺐ ﻫﻤﺒﺴــﺘﮕﯽ 1، 1 و 0/53 ﻣــﯽﺑﺎﺷــﺪ. ﻧﺘﯿﺠــﻪ ﺣﺎﺻــﻞ از ﺑﺮرﺳــﯽ روﻧــﺪ ﭘــﺎراﻣﺘﺮﻫــﺎي اﻗﻠﯿﻤــﯽ ﺑــﺎ آزﻣــﻮن ﻣــﻦ- ﮐﻨــﺪال ﻧﺸــﺎن داد ﮐــﻪ دﺑــﯽ ﺟﺮﯾــﺎن و ﺑــﺎران داراي روﻧــﺪ ﮐﺎﻫﺸــﯽ و دﻣــﺎ داراي روﻧــﺪ اﻓﺰاﯾﺸــﯽ، اﻣــﺎ ﻓﺎﻗــﺪ روﻧﺪ ﻣﻌﻨﯽدار ﺑﻮده اﺳﺖ.

The purpose of this study was to determine the RDI, SPI and SDI indices for monitoring the meteorological and hydrological droughts in Bam plain, investigate their relationships with each other, and analyze the drought characteristics in different time scales and the probability of their occurrences. The results of paired t-test revealed significant differences in the results of severity, magnitude and frequency of the SPI and RDI and the most similar characteristics were obtained between RDI and SDI. Cross correlation coefficient test results indicated a high correlation in the 48-month time scale, simultaneously, and SPI-48-RDI-48, SDI-48-RDI-48 and SPI-48-SDI-48 had the coefficients values of 1, 1 and 0.53, respectively. The results of trend studies of climatic parameters using the Mann Kendall method showed decrease in the precipitation and flow rate trends and increase in the temperature trend which were not significant.