Impacts of Climatic Variables and Cryosphere on the Future Projections of Water Cycle Components Using Observations and Hydrological Models.

Water cycle, being the critical process to advance life on earth, is essential to comprehend, especially at the mountainous topography, where the runoff generates from snowmelt and rainfall feed the rivers, which benefits millions of population. It is inevitable to devise water resources policies, future planning, and management in the environment of climate change without a complete understanding of the future projections of water cycle components (Streamflow, snowmelt runoff, rainfall runoff, evapotranspiration, and snow water storage). The two high altitude watersheds, Kings River Experimental Watershed (KREW), California, US and Jhelum River Basin (JRB), located in northern areas of Pakistan, were evaluated. Hydrological Modeling System (HEC-HMS) and Snowmelt Runoff Model (SRM) were used to estimate water cycle components. The climate data for future projections were utilized from bias-corrected Coupled Model Intercomparison Project (CMIP6) models and used in the hydrologic models to estimate water cycle components. The Distribution Mapping (DM) approach for the bias correction of the projected climate data from General Circulation Models (GCMs) was incorporated in the study. For future projections, Representative Concentration Pathways (RCP4.5 and 8.5) were used. Overall, the study help enhance the understanding of the future impacts of climate on the snow-dominated high-altitude watersheds and planning water resources using state-of-the-art modeling and observational techniques under changing climate. Keywords: Hydrological models, high-altitude, Future projections, Water cycle, Climate change, Cryosphere