Determination of crisis areas of precipitation in Iran for period of 2021-2040 by climate change

The climate change effect on future precipitation (2040-2021) of Iran is investigated in this study. For this purpose, the results of three general circulation models (GCM) named GFDL-ESM2M, HadGEM2-ES and IPSL-CM5A-LR were analyzed for two scenarios of greenhouse gas emissions RCP2.6 and RCP8.5. CCT model and daily precipitation data of the base period (1986-2019) were used to downscale and bias correction of future daily precipitation data. According to the annual results, the weighted average of annual precipitation of rain gauges due to all scenarios except RCP8.5 in the IPSL-CM5A-LR model was increasing. The weighted average of seasonal precipitation in winter increased in all of the studied climate change conditions, but in other seasons the amount of precipitation decreased or increased. The highest increase in the weighted average of seasonal precipitation was in winter due to the RCP2.6 scenario and GFDL-ESM2M model (23 mm). The highest decrease in the weighted average of seasonal precipitation was in autumn due to the RSP8.5 scenario and IPSL-CM5A-LR (10.5 mm). Slight changes in mean precipitation, on the other hand, a sharp decrease in minimum precipitation (446 mm due to G3S4) and a sharp increase in maximum precipitation (233 mm due to G2S1), indicate the occurrence of severe extreme events (drought and flood) in the future.