A comprehensive assessment of seasonal changes in future maximum temperature of Iran during the warm period based on GCM Models

Assessment of climate change impacts is quite necessary in the temperature extremes. In this study, the changes in maximum temperature of Iran were comparatively examined in two future periods (2041-70 and 2071-99) and based on the output of general circulation models of Hadcm3 under existing scenarios (A2 and B2) than the base period (1981-2010). Also, in the field of uncertainty analysis in occurrences prediction of future maximum temperature, the outputs of two general circulation models of Hadcm3 and CGCM3 under all existing scenarios (A2, A1B, B1 and B2) were carried out for comparison examination onto the results of the 7 representative climatic stations of Iran.For this purpose, after examining the ability of statistical model of SDSM in simulation of base period (2010-1981), the daily future values of maximum temperature were downscaled in the studied stations scales. The results of spatial distribution of maximum temperature showed that in the future decades, mountainous areas and high lands located in northern areas of Iran, during spring, and the central areas of Iran, during summer, will experience the greatest increase in temperature. This is while; during both seasons of warm period of the year the areas adjacent to the southern coasts of Iran will experience the lowest temperature increase. Meanwhile, the largest increase in maximum future temperature for spring and summer in compare to base period are estimated according to A2 scenario about (2-4 degrees Celsius) and according to B2 scenario about (1-2 °Cg), respectively. In uncertainties analysis related to model-scenarios, it was found that CGCM3 model under scenario B1 had the best performance in the simulation of future maximum temperatures among different scenario-models. Also, the increase in maximum temperature has been more severe based on various scenarios of Hadcm3 model than the CGCM3 model.