Welcome to GravIS, the Gravity Information Service of the German Research Centre for Geosciences (GFZ), in collaboration with the Alfred-Wegener-Institut (AWI) and Technische Universität Dresden. Data products derived from the gravimetric Earth observation satellite mission GRACE are widely used by scientists and other interested users to study mass variations in the Earth system. However, processing of GRACE data into user-friendly products for dedicated geophysical applications is nontrivial, neither when starting from original satellite observations nor from the level of gravity field products. In order to enable the usage of satellite gravimetry data for a broader community, user-friendly ('Level-3') products are generated by various institutions.
GravIS visualizes and describes Level-3 products based on the most recent GRACE data release from GFZ. All products presented at GravIS will be available for download at GFZ's Information System and Data Center (ISDC) in the near future.
The Gravity Recovery and Climate Experiment (GRACE; 2002 - 2017) and its Follow-On mission (GRACE-FO; due for launch in spring 2018) typically provide monthly independent estimates of the Earth's global gravity field. Differences between consecutive months are caused by mass redistribution and mass transport in the Earth system, particularly in the geophysical fluid layers of the atmosphere, oceans, and continental hydrosphere.
GRACE/GRACE-FO data processing is structured into sensor data analysis (Level-0 to Level-1), global gravity field estimation (Level-1 to Level-2), and geophysical mass anomaly inversion (Level-2 to Level-3). Resulting Level-3 products comprise globally gridded mass anomalies as well as basin average time series and are available for terrestrial water storage over non-glaciated regions, bottom pressure variations in ocean basins, and ice mass changes in both Antarctica and Greenland. In order to achieve the highest possible accuracy of the mass anomalies, several post-processing steps have been applied to the Level-2 spherical harmonic coefficients before inversion.