Analysis of Regional Droughts by Standardized Precipitation Index (SPI), Percent of Normal (PN) and Z Standard Indexes in Kohghiloieh and BoirAhmad Province

The identification and monitoring of drought are of great importance in the most regions of Iran. Because of a-periodic distribution of precipitation that causes many regions and many provinces of Iran are prone to drought. Kohgiloieh and BoirAhmad province is in the south west of Iran. Drought characteristics were derived for this region to identify regional drought periods and the regional coverage of droughts having a given severity. In this work we analyzed drought in Kohgiloieh and BoirAhmad province (intensity, duration, trend and area) using SPI, five time scales (3, 6, 12, 24 and 48 months) , percent of normal precipitation index and Z standard were used. Results indicate that frequency of short range droughts in the region was 13 in the period 1362-1381 but that in long range droughts, it was less, and duration in long range droughts was very long (80 months). In addition, severe droughts in the years of 1372 and 1378 covered more than 80% surface area of the region.

کلیدواژه ها:

drought ، regional droughts ، standardized precipitation Index (SPI) ، percent of normal precipitation (PN) ، Kohgiloieh and BoirAhmad