G - I
type: Concept

ICE MASS BALANCE BY SATELLITE G
type: Concept
in scheme: projects
definition: The main objective of the proposed work is the study space and time mass variations of ice mad snow over polar regions, the estimation of the water mass balance using monthly GRACE geoids for the recent period, as well as its connection with global climate change, the global hydrological cycle, and in particular the investigation on the possible causes of the sea level rise from ice melting. GRACE (Gravity Recovery and Climate Experiment) is the first geodetic mission dedicated to the measurement of the time-variations of the Earth’s gravity field, it enables the detection of water mass transfers. The on-going GRACE mission (launched in 03/2002 for a nominal lifetime of 5 years; quasi-polar orbit) provides monthly maps of tiny spatio-temporal variations of gravity due to the redistributions of mass inside the surface fluid envelops of the Earth. These satellite measurements represent vertically-integrated gravity effects of water mass reservoirs (oceans, atmosphere, continental waters and ice sheets) and of the solid Earth that need to be unravelled. Monthly solutions of the continental water storage (2002 to present) have been recently extracted from the raw GRACE geoids (at the resolution of 500 km), using an iterative generalized least-squares approach developed in our laboratory (LEGOS; Schmidt et al., 2005; Ramillien et al., 2005). After correction of important geophysical effects like mass changes induced by vertical s to study the ice sheets for the following objectives: (1) Mass balance of the ice sheets: mapping for the first time the time variations of loss/gain of ice mass observed by GRACE, in response to climate change. This will provide monthly time series and geographical maps of the integrated variations of mass over large remote regions like Antarctica and Greenland. (2) Contribution to the sea level rise: Estimating the mass balance of these polar regions, which can be further expressed in terms of sea level contribution. Recent results indicate th…