Remote Sensing of Terrestrial Water Storage Variations Using GRACE

After its launch in late 2001, the Gravity Recovery and Climate Experiment (GRACE) will measure the time variable component of Earth's gravity field with unprecedented accuracy. On land, changes in the time-variable gravity field are largely due to changes in the storage of water. Recent research indicates that GRACE observations of the time-variable gravity field, when combined with auxiliary data, will yield estimates of changes in terrestrial water storage with sufficient accuracy for applications in large-scale hydrology. These include changes in basin water storage and aquifer level variations, and potentially, changes in large lake volumes, snowpack or floodplain storage. In this presentation, past research on the potential of GRACE applications in hydrology will be briefly reviewed, and new research on sources of estimation uncertainty due to irregularly-shaped hydrologic units and due to high frequency variations in water storage will be discussed.