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Combined GRACE and InSAR estimate of West Antarctic ice mass loss

Publication at Faculty of Mathematics and Physics |
2010

Abstract

We estimate the mass balance of eight drainage basins in West Antarctica from the Gravity Recovery and Climate Experiment (GRACE) data (GFZ RL04, GSM Level 2) using a constrained inverse‐gravimetric approach. We consider InSAR observations of ice surface velocity as an indication of mass change, assuming that large mass loss occurs in areas of fast glacier flow.

From these mass distribution functions we construct forward models of the geoid height change and their spatial correlations for each drainage basin. Then the difference between the GRACE data and the forward model is minimized by adjusting the total amount of mass change within each drainage basin.

To overcome the ambiguity inherent in this inverse problem, we constrain its solution by including a priori estimates based on the InSAR mass‐budget method. However, unconstrained (GRACE only) mass‐change estimates can be recovered for three to four combined drainage basins.