We use satellite solutions to the low degree zonal coefficients of the Earth’s gravitational potential, J 2 through J7, to reveal large scale features of rates of thickness change of the polar ice sheets, and the lower mantle viscosity. The polar ice sheets may each be divided into two regions, whose change in thickness and shape were adjusted to predict gravity that agrees well with observation. If the postglacial rebound model of Han and Wahr  is used, the predicted viscosity is 1 X 1022 Pa-s, predicted sea level rise from Antarctica is 0.1 ±0.8 mm/yr, and the sea level rise from Greenland is 0.4 ± 0.3 mm/yr. The total meltwater from both ice sheets is 0.5 ± 1.1 mm/yr.We also set the thickness change over 63 per cent of the grounded Antarctic ice sheet equal to the ERS satellite altimeter measurements and compute the variation of thickness change for Greenland. This can be done with J 2 through /5. The incomplete coverage of Antarctica makes the determination of lower mantle viscosity uncertain, but, if we assume this viscosity 1 X 1022 Pa-s, then the predicted combined sea level rise remains 0.5 ±1.0 mm/yr.
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- Determination of Mass Balance of Polar Ice from Gravity
Andrew S. Trupin
C. K. Shum
- Springer Berlin Heidelberg
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