Sea level is rising and this trend is projected to increase over the next century

The water budget over the global land surface plays an important part in altering the rate of this change. Several over-land water cycle storages contribute to this change: pumping of groundwater glacier melt endorheic drainage basins permafrost thaw and draining of thermokarst lakes. There is significant regional and temporal variability often masking the long-term trend in water storage change that can be a significant contributor to sea level over long time scales. The overall goal of this proposed work is to provide land surface hydrological cycle change projections along with estimates of uncertainty and trends in terms of over-land total water storage pertinent to sea level rise. We will use a water balance model (WBM) to account for major natural and anthropogenic hydrologic cycle processes. Historical runs will be used to evaluate the model compared to grace total water storage. Discharge data from in situ observations as well as data from remotely sensed arctic discharge reanalysis (RADR) and new products based on the NASA swot mission will also be applied for model evaluation. Future projections will generate a large suite of WBM runs using a large set of climate drivers from CMIP5/6/7 and downscaled products. A diverse set of runs is important to capture the range of variability and will be used to characterize the uncertainty of the land water flux to the ocean.