Spatial Distribution of Meteorological Drought in Northern Karun Basin

Scientific investigation of drought is essential for water resources management, and reduction it's consequences. But point data of rain is available, where drought affect a range of land. The purpose of this study is spatial analysis of meteorological drought intensity, using geostatistical Kriging in Northern Karun Basin. For this purpose, the standardized precipitation index (SPI) was calculated for 24 rain stations in the area using DIC software.Then, spatial distribution of SPI was determined with ordinary Kriging (OK) submodels: spherical, exponential, linear, Gussian, and linear-to-sill for three years (normal, extremely dry and moderately wet). The results of varigram analysis and error criteria indicated that the geostatistical method Kriging with exponential model due to have lower error rates, has the higher ability in SPI zoning. Finally, the zoning maps if SPI in North Karoun Basin show that in 2007 (extremely dry), drought intensity is higher in eastern parts of basin specially in Broojen station and northern parts of basin like Dashtak, Hiregan and Shahrekord Stations have received more precipitation in 2005 (moderately wet) compared to the rest of the basin. Distribution of drought intensities could be due to rein production fronts and mountainous range direction.