Twenty-first century hydrologic and climatic changes over the scarcely gauged Jhelum river basin of Himalayan region using SDSM and RCPs

Climatic and hydrological changes of the scarcely gauged mountainous basins remain a challenge to study due to unavailability of observed data. The recent study aims to assess these changes using spatial decision tool statistical downscaling method (SDSM) and snowmelt runoff model (SRM) for the twenty-first century under representative concentration pathways (RCPs). SDSM considered absolute partial correlation coefficient (abs. Pr.) to evaluate efficiency predictors or the predictands of the Jhelum river basin. The performance evaluation of SDSM assessed using coefficient of determination (R2) values for RCP 4.5 and RCP 8.5 under CMIP5 (CCSM4). The biases of the daily time series downscaled data removed by using mean-based biased correction method (MB-BC). Stream projection carried out using SRM by incorporating MODIS snow product. Statistical parameters R2 and volume difference (Dv %) calculated for accuracy assessment of SRM for the simulated and observed discharge (2001–2018). Streamflow projections for the twenty-first century carried out by SRM using de-biased downscaled data. The R2 indicator of SDSM ranged between 78–81% for temperature and 82–86% for precipitation under RCP 4.5 and RCP 8.5, respectively. The temperature results indicated an increasing trend of 1.5oC and 3.8oC for the twenty-first century under RCP 4.5 and RCP 8.5, respectively. The mean annual precipitation showed a rise of 2–7% while surface runoff projected a rising trend of 3.3–7.4% for RCP-4.5 and RCP-8.5 respectively till the end of the twenty-first century. The study results revealed that Jhelum basin will be wetter and warmer for the twenty-first century as compare to the baseline period. The hydrographs of the river predicted the occurrence of more extreme events in the region for the twenty-first century. These hydrographs may help for better water conservation and management strategies in the Jhelum basin for the twenty-first century.