The GRACE Mission: Status and Future Prospects

The mass transport between the earth's atmosphere, oceans and solid earth is a critical component of global climate change processes and is an important component of the signals associated with global sea level and polar ice mass change, depletion and recharge of continental aquifers, and change in the deep ocean currents. This mass exchange has a gravitational signal, which can be monitored as an indication of the mass exchange process. The Gravity Recovery and Climate Experiment (GRACE) is a joint NASA and DLR mission whose purpose is to improve our understanding of the Earth's dynamical system by making pioneering measurements of the gravity signals associated with mass exchange between its components. The twin satellites involved in the GRACE mission were launched on March 17, 2002 and initiated scientific measurements in May 2002. The mission completed a six-year measurement sequence in March 2008. During this interval, GRACE has provided an accurate measurement of the time-variability and long-term mean mass distribution of the Earth's dynamic system. During the six-year interval, GRACE has provided global measurements of mass flux between the land, ocean, atmosphere and the cryosphere with un-precedented detail and accuracy. In this presentation, we will summarize the state of the GRACE mission, and describe plans for the coming years. We will survey the state of the multi-disciplinary science applications of the GRACE mission that are conducted in conjunction with various satellite missions (TOPEX/Poseidon, Jason-1, ICESat, GOCE) and discuss the scientific concerns for a Grace Follow-on Mission.