Prediction of Climate Change using General Circulation Models and SDSM and LARS-WG Downscaling Models under RCP Scenarios in Dez Watershed

Climate change is one of the greatest challenges facing humanity in the 21st century. Therefore, prediction of climate change is very important to predict the future situation and to consider the necessary measures to adjust and adapt to climate change. Therefore, in this study, climate change was predicted in the Dez watershed. For this purpose, the data of two global models HadGEM2 and CanESM2 were used under three scenarios RCP2.6, RCP4.5 and RCP8.5 and the application of two downscaling models of LARS-WG and SDSM and the climate changes in the next three periods compared to the base period (1989-2018) were examined. The results showed that both downscaling models have good accuracy in simulating climate change in the study watershed. The results of prediction the studied models also showed that in the future periods the amount of precipitation in the watershed will change between -6.3 to 15.7% compared to the base period. The most decreasing and increasing changes will be related to the eastern and southwestern areas of the watershed, respectively. Also, the maximum temperature of the watershed will fluctuate between 1.3 to 3.9 oC and the minimum temperature will fluctuate between 1.5 to 3.5 oC. The highest and lowest changes will be related to the southeastern and northwestern areas of the watershed, respectively. Therefore, due to the increase in temperature and precipitation, as well as the mountainous nature of the watershed under study, it is necessary to consider flood control and containment and management strategies.