Temporal and Spatial Analysis of Drought with use of SPI Index in Iran

In this study the temporal and spatial patterns of drought with the use of daily precipitation data of 30 synoptic weather stations for common period of forty years, and for five temporal series (3-, 6-, 12-, 24- and 48-month) by using SPI index, with three characteristics of intensity, frequency and duration on a national scale were investigated. The results show drought's maximum frequency in the 3- and 6-month scale in the extremely dry category is Sanandaj Station. In the 6-month scale in the moderately dry category is Ahvaz Station, in the severely dry category is Noshahr Station, and in the extremely dry category is Sanandaj Station. In the 12-month scale in the moderately dry category is Orumieh Station, in the severely dry category is NoshahrStaion, and in the extremely dry category is BabolsarStaion. In the 24-month scale in the moderately dry category is Bandar Abbas staion, in the severely dry category is Noshahr Station, and in the extremely dry category is Ramsar Station. In the 48-month scale in the moderately dry category is Bandar Abbas station and among of two other stations, Noshahr Station has the drought's maximum frequency. Moreover, the highest intensity is occurred in Semnan Station in the 3-monthscale with amount of -3.89.