Investigation of Climate Change Impact on 24-h Probable Maximum Precipitation in a Sub-humid Climate

In this study, the impact of climate change on 24-h probable maximum precipitation (PMP24) was investigated in a part of Qareh-Su basin located in Golestan province. For this purpose, the daily and hourly climatic data during years 1987–2017 were applied. In order to generate future data, the outputs of CanESM2 model as a general circulation model (GCM) under three emission scenarios including optimistic (RCP 2.6), middle (RCP 4.5) and pessimistic (RCP 8.5) and statistical downscaling model (SDSM) were used in two near and far future periods. The PMP24 values were estimated using physical, Hershfield standard and revised methods in the baseline and future periods under the three scenarios. The PMP24 value was estimated 421 mm for the baseline period, using Hershfield standard method. These values under the three RCP scenarios were obtained 202, 228, and 213, for the near future and 216, 201, and 230 mm for the far future. The result of Hershfield revised method was 230 mm for the baseline period. The PMP24 values under the three scenarios were calculated 81, 85, and 76 mm for the near future, and 83, 80, and 79 mm for the far future. The PMP24 resulted from physical method was 143 mm for the baseline period. These values were 98, 105, and 109 for the near future, and 129, 122, and 126 mm for the far future period.