Abstract:

We have developed techniques that convert the GRACE gravity data into spatially-averaged water storage estimates. Applying these techniques to the GRACE gravity fields, we have derived regional estimates of water storage variations for specific regions of the world. We compare these estimates to those produced by macroscale hydrologic models, as well as remotely-sensed estimates of snow water. In addition to providing direct estimates of water storage change, GRACE data can be used to estimate other components of the water cycle as residuals by combining GRACE water storage estimates with estimates of other quantities, such as precipitation and river discharge, in the appropriate water balance equation. We also compare estimates of precipitation minus evapotranspiration made using this approach to those obtained from both hydrologic models and global circulation models.