Simulation and spatiotemporal analysis of meteorological Drought in Karoon, Karkhe, and Dez basins

Drought is one of natural disaster that unlike of others has gradually essence. It causes economic، social and environmental damages such as famine، waning civilization and ecosystem changes. Drought analyzing has a main role to recognize its essence that leads to reduce harmful effects. In this paper the meteorological drought has been analyzed in Karkhe، Karoon and Dez basins. In outset monthly rain was modeled by a method that includes empirical orthogonal function’s (EOF)، stochastic modeling and Kriging interpolation. Based such method the homogenous regions were determined in mentioned basins. The four regional time series of PC that explained 86. 9% of variance were modeled by stochastic modeling then time series of monthly rain was produced as long as 1000 years for every 291 cells. Meteorological drought was analyzed by method of truncation level (at 70% level) for every one of cells and drought characteristics includes of severity، duration، effected area، total of deficit volume، and relative deficit volume were calculated. After classifying drought according percentage affected area return periods of droughts، duration and deficit volume were calculated by fitting the best probability distribution models. Then severity-area-frequency (SAF) and duration-area-frequency (DAF) curves were concluded.