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AGU: Geophysical Research Letters

 

Keywords

  • Antarctica
  • Greenland
  • gravity
  • oblateness

Index Terms

  • Geodesy and Gravity: Time variable gravity (7223, 7230)
  • Geodesy and Gravity: Mass balance (0762, 1223, 1631, 1836, 1843, 3010, 3322, 4532)
  • Geodesy and Gravity: Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions (0762, 1218, 3319, 4550)
  • Geodesy and Gravity: Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
  • Global Change: Cryospheric change (0776)

Abstract

GEOPHYSICAL RESEARCH LETTERS, VOL. 38, L13501, 6 PP., 2011
doi:10.1029/2011GL047879

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

Key Points
  • The Earth's oblateness has been changing
  • GRACE shows this change is caused by melting ice in Greenland and Antarctica
  • This suggests the polar ice might be responsible for the recent J2 changes

R. S. Nerem

Colorado Center for Astrodynamics Research, Aerospace Engineering Sciences, University of Colorado at Boulder, Boulder, Colorado, USA

Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, Colorado, USA

J. Wahr

Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, Colorado, USA

Department of Physics, University of Colorado at Boulder, Boulder, Colorado, USA

We use temporal gravity variations from GRACE to investigate changes in a 34-year time series of Earth's oblateness (J2) observed by satellite laser ranging (SLR). We use 2002–2010 GRACE data to compute the effects of Greenland and Antarctic ice mass variations on J2 (2.0 and 1.7 × 10−11/year respectively). Their combined effect on the J2 trend during the GRACE mission is 3.7 × 10−11/year, which agrees well with the GIA-corrected SLR J2 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 J2 trend, which apparently began sometime in the 1990s.

Received 20 April 2011; accepted 26 May 2011; published 13 July 2011.

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.

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