Monitoring and Regionalization of Meteorological Drought in Karkhe Watershed Using Standardized Precipitation Index and Precipitation Deciles

Drought is one of the most important natural hazards which usually happens in different regions of Iran. This study was conducted in order to determine meteorological droughts in Karkhe watershed according to precipitation data for 12 meteorological stations using SPI and Deciles indices. The data homogeneity was examined by run test performance. Then all the required data were prepared for 9, 12 and 24-month SPI's and annual deciles were computed. Drought intensity and percent of drought frequency were regionalized using Kriging method for both SPI and decide of 10 percent. The results showed that at first droughts happen in short time scales of SPI and if drought conditions continue, they will happen in longer time scales. Meteorological drought intensity and percent of drought frequency decrease from west to east of Karkhe watershed. Also, if the drought frequency percent (the ratio of drought periods to total record periods) increases, the drought intensity will increase.