HR: 11:20h
AN: G31C-05    [PDF]
TI: Earth Tides, Mantle Anelasticity, and the Post-1998 Change in the Earth's Oblateness
AU: * Benjamin, D
EM: David.Benjamin@colorado.edu
AF: Dept. of Physics and CIRES, U of Colorado, Boulder, CO 80302 United States
AU: Wahr, J
EM: wahr@lemond.colorado.edu
AF: Dept. of Physics and CIRES, U of Colorado, Boulder, CO 80302 United States
AU: Desai, S
EM: Shailen.D.Desai@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 United States
AB: A large change in the Earth's oblateness that apparently began in 1998, was recently detected using satellite laser ranging data (Cox and Chao, 2002). The characteristics of this anomaly, though, are sensitive to the way in which the 18.6-year tidal contributions are modeled. Results obtained by fitting and removing in-phase and out-of-phase 18.6 year terms, suggest that the anomaly could, instead, be part of a quasi-periodic perturbation with an approximately 10-year cycle. The results we obtain for the 18.6 year tide, combined with other earth tide and earth rotation estimates, are consistent with an anelastic model of the Earth that assumes a frequency-dependence for Q that is in rough agreement with that inferred from laboratory measurements.
DE: 1214 Geopotential theory and determination
DE: 1249 Tides--Earth
DE: 1645 Solid Earth
DE: 3909 Elasticity and anelasticity
DE: 8162 Rheology--mantle
SC: Geodesy [G]
MN: 2003 Fall Meeting