What Might GRACE Contribute to Studies of Post Glacial Rebound?
The NASA/DLR satellite gravity mission GRACE, launched in March, 2002, will map Ihe Earth’s gravity field at scales of a few hundred km and greater, every 30 days for five years. These data can be used to solve for time-variations in the gravity field with unprecedented accuracy and resolution. One of the many scientific problems that can be addressed with these time-variable gravity estimates, is post glacial rebound (PGR): the viscous adjustment of the solid Earth in response to the deglaciation of the Earth’s surface following the last ice age.
In this paper we examine the expected sensitivity of the GRACE measurements to the PGR signal, and explore the accuracy with which the PGR signal can be separated from other secular gravity signals. We do this by constructing synthetic GRACE data that include contributions from a PGR model as well as from a number of other geophysical processes, and then looking to see how well the PGR model can be recovered from those synthetic data. We conclude that the availability of GRACE data should result in improved estimates of the Earth’s viscosity profile.
KeywordsSatellite Laser Range Lower Mantle Uppermost Mantle Lithospheric Thickness Viscosity Profile
Unable to display preview. Download preview PDF.
- Beck, J.V., and Arnold, K.J.: 1977, Paranzeter Estimation in Engineering and Science, 501 pp.’ Wiley. New YorkGoogle Scholar
- Chao, BR, and Gross, R.S.: 1987, ‘Changes in the Earth’s rotation and low-degree gravitational held induced by earthquakes’. Geophys. I R. Astron. Soc. 91, 569–596.Google Scholar
- Cheng, M. K., ShLIm, C. K., and Tapicy, B.: 1997, ‘Determination of long-term changes in the Earth’s gravity field from satellite laser ranging observations’, J. Geophys. Rex. 102, 22,377–22, 390.Google Scholar
- Church. iA., Gregory. i.M., et al.: 21, Changes in sea level, in Climate change 2001: The Science of Climate Change: contribution of Working Group I to rile Second Assessment Report of the Intergovernmental Panel on Climate Change, edited by.J,T, Houghton, l-.G. Meira Fitho. BA. Callander, N. Harris, A. Kattenberg, and K. Maskell. Cambridge Univ. Press, New York, 503–555, in press.Google Scholar
- Dickey, J.O., ci al.: 1997, Satellite Gravity and the Geosphere: Contributions to the Study of the Solid Earth and Its Fluid Envelope, 112 pp.. Nail. Aead. Press, Washington. D.C.Google Scholar
- Dukowicz, i.K., and Smith. R.D.: 1994. ‘Implicit free-surface method for the Bryan-Cox-Semtner ocean model, I Geophn. Rex. 99. 7991–8014.Google Scholar
- Dziewonski, A., and Anderson, D,L.: 1981, ‘Preliminary reference Earth model’, Phys. EarthPlaner. Inter 25, 297–356.Google Scholar
- European Centre for Medium-Range Weather Poreasts: 1995, The description of the ECMWF/WC’RP level 111-A global aonospheric data archive. Data Services publication, Reading, England.Google Scholar
- Kalnay, E., et al,: 1996, ‘The NMCINCAR 40-year reanalysis project’. Bull. Am. Meteorol. Soc. 77. 437–47 I.Google Scholar
- Tushingham, AM., and Peltier, W.R.: 991, ‘ICE-3G: A new global model of late Pleistocene deglaciation based upon geophysical predictions of postglacial relative sea level change’, J. Geophys. Res. 96, 4497–4523.Google Scholar
- Velicogna, I. and Wahr, J.: 2002a, ‘Post Glacial Rebound and Earth’s Viscosity Structure From GRACES, J. Geopkys. Res., submitted.Google Scholar
- Velicogna. I. and Wahr, J.: 2002b, ‘Post-glacial rebound and ice mass balance in Antarctica from 1CESaIIGLAS, GRACE and GPS measurements’, I Geaphys. Res., in press.Google Scholar
- Wahr, 1., Molcnaar, M., and Bryan. F: 1998, ‘Time-variability of the Earth’s gravity held: hydrological and oceanic effects and their possible detection using GRACE’, J. Geophys. Rex. 103, 30,205–30, 230.Google Scholar
- Wahr. J., Wingham, D.. and Bentley. C.R.: 2000, ‘A method of combining GLAS and GRACE satellite data to constrain Antarctic mass balance’, J. Geophys. Rex. 105. 16,279–16. 294.Google Scholar
- Wu, X., Watkins, M., Kwok, R., Ivins, E., and Wahr,J.: 2002, ‘Measuriog present-day secularchange in Greenland ice mass with future GRACE gravity data’, I Geophys. Rex., in press.Google Scholar