Frequency Analysis of Regional Meteorological Drought in Karun-1 Basin of Iran

Due to severe fluctuations in rainfall in different regions of Iran, droughts are amongst natural disasters which occurs in negative fluctuations, when rainfall is lower than long term average and forcing adverse effects on agriculture and economy. Meteorological drought is one of the droughts that occurs in the earliest stages of drought phenomenon. In this study, using standardized precipitation index (SPI) the status of meteorological drought is reviewed and linear moment method is used to analysis regional frequency. For regional analysis, with linear moment method, a computer program, developed by Hosking, is used. After surviving distorted criterion and homogenous degree criterion, it be came clear that one of the stations of Karun basin 1, has distorted criterion. Also, the results of goodness-of-fit criteria showed that the pearson distribution type III, can be fitted regionally for whole region. So this distribution will be used to analysis drought indexes in this area.