Assessment of Climate Change Impact on Precipitation and Temperature Variation in Watershed of Karoon 3 Dam

This study aimed at investigating climate change impacts on precipitation and temperature variations in the watershed of Karoon 3 Dam using LARS-WG statistical model in the future. For this purpose, the climate data of 10 atmospheric general circulation models (GCM) were used under three distinict emission senarios in the watershed of Karoon 3 Dam. The precipitation and temperature parameters of the study area were simulated for 2011-2099 using the data of 1980 - 2007 in six synoptic stations. First, mean monthly precipitation was calculated using daily data by Inverse Distance Weighted interpolation method. In order to investigate six months’ precipitation variation, the summation of 6, 12, and 24 months’ precipitation were calculated.The model calibration and verification was evaluated using LRAS-WG5 model for the base year (2007-1980) in order to determine the production feasibility and simulation of meteorological data in future periods. Using atmospheric GCM and the IPCC climate change scenarios, the simulation and production of meteorological data was performed for future periods. The monthly precipitation and minimum and maximum temperature difference were analyzed. The research showed thatdifference between monthly maximum and minimum temperature decreases under climate change in spring and summer. Spring precipitations increase while summer and autumn precipitations decrease. The most increase of precipitation takes place in winter and in January. Moreover, the results showed that the frequency of normal and wet years with respect to the long-term average rainfall in the area was more in B1 and A2 emissions scenarios compared with A1B.