ITSG-Grace2016 - Daily Gravity Field Solutions from GRACE

The Gravity Field And Climate Experiment (GRACE) has granted invaluable insight into the redistribution of surface mass by providing monthly snapshots of the Earth’s gravity field. Highly dynamic events such as floods, which can build up and drain on time scales from hours to weeks, are however difficult to capture with the comparatively coarse sampling rate of one month. ITSG-Grace2016 is the latest time series of GRACE solutions computed at Graz University of Technology (TU Graz), providing daily, global, Kalman smoothed gravity field snapshots. The release covers the complete GRACE observation time span starting from April 2002 and is continuously updated. The processing strategy applied is also the basis of the EGSIEM (European Gravity Service for Improved Emergency Management) Near Real-Time Service aiming to provide daily gravity field solutions with a maximum delay of five days. The service will be jointly run by GFZ (German Research Centre for Geosciences) and TU Graz, with each analysis center providing an independent solution.
We show the added value of the daily solutions by comparison with in-situ data and output from different global hydrological models. High frequent variations in river discharge are well reflected in the GRACE derived total water storage anomalies for mid- to large scale flood events. These comparisons suggest that daily GRACE products contain high-frequency gravity field information and represent a suitable data source for the monitoring of hydrological extreme events.