The Study of Drought and Climate Change in Perioud Future By Using Genral Circulation Atmosphere Model Case study: Gorgan roud - Ghrasou - IRAN

Climate change, especially on account of greenhouse effect, has created disastrous problems in recent years directly or indirectly affecting different sectors in Iran. One of the most important misfortunes is the increase of climate and environmental crises such as flood, drought, tropical cycles, sea level rise and the dust storm, the commonest of which in Iran are flood and drought. In this study, by using GCM model (two models of ECHAM4 and hadCM3) and down scaling the output by the help of statistical models of LARS_WG, raining data for the next period and also for the next 20-year period (from 2011 to 2030) were calculated. Afterwards, by the use of drought criteria (ZSI,PN,SPI) , the drought condition in Gorganrood-Gharehsou Basin were studied.. Moreover, droughts in a basic 20-year period from 1989 to 2008 were analyzed and the frequency and strength of the droughts compared to the next period were studied. The results, while proving the criteria for the study of drought, showed that in the following years drought will be increased compared to the basic period. This proves the climate change in the region. Moreover, rain patterns in winter will change and thereof there will be drought problems in next periods.