Projected Changes in Temperature and Precipitation over Kashafrood Basin Based on Statistical and Dynamical Downscaling Methods

It is well-known that climate is changing continuously under the intricate influences of natural and artificial factors at global and regional scales. The global Coupled Model Intercomparison Project (CMIP) already provides multi model data resources in order to improve the scientific research for investigating the vulnerability of climate change and future climate risk at regional or local scales and then developing the corresponding adaptation strategies. Global climate models (GCMs) have proven to be unable to resolve the details of regional climate change features because of the limitation of their coarse resolution. To bridge these gaps, downscaling methods, that is, statistical and dynamical downscaling, are multi method ways to get fine resolution projections of GCMs.Since the provision of robust climate information with a multimodel, multimethod, and multiscale (M5S) method can assist decision-making responding to climate change in agriculutral and water sectors, this study aims to provide the climate change scenarios of temperature and precipitation over Kashafrood Basin (KB) using three downsclaing methods. In this study the CanESM model outputs have been downscaled using two statistical downscaling methods (BCSD and SDSM) and one regional climate model (RegCM) during the period of 1984-2005 and the near future period (2021-2050) under RCP4.5. Results show that the mean temperature is projected to increase in the Kashafrood basin throughout all seasons. Precipitation changes exhibit a larger variability. By the end of the near future, an annual precipitation decrease by 4% and 9% are projected under RCP4.5 based on SDSM and RegCM model respectively in Mashad station, while an increase of over 24% is projected using BCSD downscaling method which is statistically significant.