Recent changes in the Earth's oblateness driven by Greenland and Antarctic ice mass loss

摘要

We use temporal gravity variations from GRACE to investigate changes in a 34-year time series of Earth's oblateness (J_2) observed by satellite laser ranging (SLR). We use 2002-2010 GRACE data to compute the effects of Greenland and Antarctic ice mass variations on J_2 (2.0 and 1.7 × 10~(-11)/year respectively). Their combined effect on the J _2 trend during the GRACE mission is 3.7 × 10 ~(-11)/year, which agrees well with the GIA-corrected SLR J_2 trend over the same time period. The results suggest that at least since 2002, ice loss from Greenland and Antarctica has been the dominant contributor to the current GIA-corrected J_2 trend, which apparently began sometime in the 1990s.