Application of a quantitative screening approach in statistical downscaling model (SDSM) to generate climate change scenarios (Case study: the Gorgan-roud River Basin)

In this research, the performance of the SDSM in downscaling of three variables including precipitation, minimum temperature, and maximum temperature in Gorgan-roud River Basin was examined. Screening the predictor variables was done using a quantitative approach. Considering the efficiency of the SDSM to downscale the CanESM2 outputs at the scale of Gorgan-roud River Basin, the model was used to downscale the mentioned variables under two scenarios of RCP2.6 and RCP8.5 for three time periods of 2006-2040, 2041-2070, and 2071-2100. Also, the trend of mentioned changes was examined for the period of 2006-2040. Based on the results, under two scenarios, amount of precipitation will show an increase in the stations of Tamer, Cheshme Khan, Bahlake Dashli, and Ghafar Haji for the three time periods In contrast, precipitation will decrease for the stations of Gorgan and Arazkouse. In addition, amount of minimum temperature will increase during the explored time periods under two scenarios for the stations of Gorgan, Cheshme Khan, and Arazkouse (except in the period of 2071-2100 under RCP8.5) and will show a reduction for the stations of Tamer, Bahlake Dashli, and Ghafar Haji. Amount of maximum temperature during all three time periods and under two scenarios will increase in the stations of Gorgan, Tamer, Cheshme Khan and Arazkouse and will decrease in the stations of Bahlake Dashli and Ghafar Haji. In general, a single direction in the change of the climate variables cannot be projected across all stations investigated.