Investigating spatiotemporal variations of precipitation and temperature over Iran under climate change condition considering AOGCM models and emission scenarios uncertainty

Climate change impacts on precipitation and temperature world-wide are not yet well understood (especially for precipitation), due to their complexity and regional variability. In this study In order to explicit the impact of climate change on Precipitation and temperature in Iran, 15 AOGCM whose greenhouse gases scenarios ran under A2, A1B and B1 were used. Monthly precipitation and temperature data were calculated for 21 synoptic stations for two future periods (2016-2045 and 2070-2099) under all of three scenarios. Result showed that increases in temperature during summer months are higher in comparison with the winter months for both future periods. All three emission scenarios predict same increase in temperature (approximately 1 to 1.5oC) for the first future period while A2 and B1 scenarios predict the highest and lowest increase in temperature over the period of 2070-2099, respectively. It is expected that mean temperature of Iran increases about 3.5oC for the areas close to Caspian Sea and central regions and 4.5oC for other regions under the A2 critical scenario. It is also found that precipitation amounts will be increased in Gilan province and also slightly in Ardabil Province under second future period while the precipitation amounts will be decreased in other regions. Generally, it can be concluded that annual precipitation volume of Iran will be decreased about 1.02 (0.25 percent) and 16.52 billion cubic meter (4.13 percent) for the first and second periods, respectively.