Assessment of groundwater storage derived from IPCC models, and projections for the next 50 years

We compare estimates of groundwater storage from the GRACE mission to values derived from IPCC simulations. Published work has shown that GRACE water storage estimates are consistent with observations for many of the western river basins (Columbia, Klamath, San Joaquin, Sacramento, and Colorado (within Arizona)); GRACE data can therefore serve as a proxy for groundwater storage data, and can be used to validate hydrological output from IPCC models. Based on this, we can then examine groundwater projections for the next 50 years for the Western US. Preliminary results from the GISS model show good correlations with GRACE data for the upper Midwest region, which is relatively well covered by both model grid points and GRACE observations. These results will be shown, along with projections for both the Midwest and the western states, especially California. The results from this project can be used with existing hydrologic forecasting tools to improve long-term water management planning.