Extending the GRACE Data Record with Gravity Field Solutions Based on a Single GRACE Satellite

Abstract:

Since 2002, the Gravity Recovery and Climate Experiment (GRACE) has enabled unprecedented scientific discovery in a variety of physical Earth sciences. However, with the launch of GRACE Follow-On not taking place until 2017 and the declining health of the current GRACE satellites, it is necessary to cultivate the ability to estimate the Earth’s gravity field without the full suite of GRACE measurements. Using a single GRACE satellite, equipped with an accelerometer and a GPS receiver, as well as a compliment of SLR satellites, large-scale features of the Earth’s gravity field can be determined. While the accuracy of such solutions are noticeably degraded relative to the nominal GRACE product and smaller-scale features of the Earth’s gravity field are impossible to discern without the use of GRACE’s satellite-to-satellite (SST) tracking measurements, single satellite solutions do capture continental scale variations in the Earth’s gravitational field. These large-scale variations can be used to track global trends such as polar ice loss and water storage, in the event of a gap between GRACE and GRACE Follow-On. In addition, the lessons learned from gravity field solutions computed using only GRACE GPS data provide valuable insight into the optimal combination of GPS data with SST for GRACE Follow-On and other future missions.