Earth Science and future satellite gravity missions

Reiner Rummel
Institute of Astronomical and Physical Geodesy, Technische Universität München, 80290 München, rummel@bv.tum.de

Among of the most important processes related to climate change are the melting of the large ice shields and of the Arctic sea ice, a possible slow down of the Atlantic branch of the global conveyor belt, changes in the global water cycle and in continental water stocks and sea level rise. It is typical to them that they are associated with temporal changes of the oceanic, ice or land surfaces and/or with mass redistribution. Radar and laser altimetry as well as positioning with GNSS proves to be very successful in the determination of geometric surface changes; GRACE is currently providing accurate time series of mass changes, and GOCE is expected to deliver the geoid surface - serving as reference surface of ocean circulation - with very high spatial resolution. This means, geodetic space techniques are capable of providing metric and weight of some of the key climate parameters with very high accuracy.

GGOS is offering the necessary framework for a long-term monitoring of the processes listed above and of geophysical fluids in general. An important requirement is thereby an un-interrupted time series of gravity variations, in the way currently provided by GRACE.