HR: 1340h
AN: G33B-1239    [Abstracts]
TI: Climate Interpretations of GRACE Gravity Field Data: Implications of the Accuracy of the ICE- 5G(VM2)GIA Model for the Inference of Mass Loss from the Antarctic Ice Sheet
AU: Drummond, R
EM: rmarie@atmosp.physics.utoronto.ca
AF: Department of Physics, University of Toronto, 60 St George Street, Toronto, ON M5S 1A7, Canada
AU: * Peltier, W R
EM: peltier@atmosp.physics.utoronto.ca
AF: Department of Physics, University of Toronto, 60 St George Street, Toronto, ON M5S 1A7, Canada
AB: Application of the ICE-5G(VM2)GIA model to the interpretation of RL04 GRACE data from the CSR demonstrates that this model delivers a highly accurate prediction of the time dependent gravity field over the North American continent. In this region the signal is dominated by the contribution of the ongoing process of glacial isostatic adjustment to the removal of the ancient Laurentide ice-sheet that once covered the region. When the GRACE field is filtered by the removal of the ICE-5G(VM2) prediction, significant residuals exist over both Greenland and Alaska that must be attributed to the melt-back of land ice from these regions due to high latitude climate warming. The corrections in these regions due to Late PLeistocene deglaciation are small. For Antarctica, however, the inferred rate of mass loss depends entirely upon the GIA correction, with a state of near modern day mass balance being inferred in the absence of the application of a GIA correction and a significant rate of mass loss being implied when such a correction is applied to the raw data. Using the latest masscon solutions for the inference of the rate of surface mass loss from Antarctica (Luthcke et al., personal communication), corrected for the influence of GIA using the ICE-5G(VM2) model, one infers a rate of mass loss from Antarctica of approximately 105 Gt/annum. The issue of the accuracy of the ICE-5G(VM2) model for Antarctic applications is therefor extremely important.The presentation will address this issue in detail.
DE: 1213 Earth's interior: dynamics (1507, 7207, 7208, 8115, 8120)
DE: 1217 Time variable gravity (7223, 7230)
DE: 1218 Mass balance (0762, 1223, 1631, 1836, 1843, 3010, 3322, 4532)
DE: 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions (0762, 1218, 3319, 4550)
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
SC: Geodesy [G]
MN: 2007 Fall Meeting