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

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.