Time-variable gravity observations of ice sheet mass balance
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Material Information

Title:
Time-variable gravity observations of ice sheet mass balance precision and limitations of the GRACE satellite data
Series Title:
American Geophysical Union
Creator:
Velicogna, I.
Wahr, J.
Publisher:
American Geophysical Union
Publication Date:
Language:
English

Subjects

Subjects / Keywords:
Climate Change ( lcsh )
Ice Sheets ( lcsh )
Gravity ( lcsh )

Notes

Abstract:
Tie-variable gravity data from the Gravity Recovery And Climate Experiment (GRACE) mission have been available since 2002 to estimate the mass balance of the Greenland and Antarctic Ice Sheets. We analyze current progress and uncertainties in GRACE estimates of ice sheet mass balance. We discuss the impacts of errors associated with spherical harmonic truncation, spatial averaging, temporal sampling, and leakage from other time-dependent signals (e.g. Glacial Isostatic Adjustment (GIA)). The largest sources of error for Antarctica are the GIA correction, the omission of l=1 terms, non-tidal changes in ocean mass, and measurement errors. For Green- land, the errors come mostly from the uncertainty in the scaling factor. Using Release 5.0 (RL05) GRACE finds for Jan 2003 through Nov 2012, we find a mass change of -258 ACK 41 Gt/yr for Greenland, with an acceleration of -31 ACK 6 Gt/yr2, and a loss that migrated clockwise around the ice sheet margin to progressively affect the entire periphery. For Antarctica, we report changes of -83 ACK 49 and -147 ACK 80 Gt/yr for two GIA models, with an acceleration of -12 ACK 9 Gt/yr2 and a dominance from the southeast pacific sector of West Antarctica and the Antarctic Peninsula. ( English )

Record Information

Source Institution:
Florida International University
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