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

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 x 10(-11)/year respectively). Their combined effect on the J(2) trend during the GRACE mission is 3.7 x 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. Citation: Nerem, R. S., and J. Wahr (2011), Recent changes in the Earth's oblateness driven by Greenland and Antarctic ice mass loss, Geophys. Res. Lett., 38, L13501, doi:10.1029/2011GL047879.