seasonal surface mass loading; mass conservation; space geodesy
Abstract :
[en] Increasingly, models of surface mass loads are used either to correct geodetic time coordinates by removing seasonal and other ‘‘noise’’, or for comparison with other geodetic parameters. However, models of surface loading obtained by simply combining the mass redistribution due to individual phenomena will not in general be self- consistent, in that (i) the implied global water budget will not be mass-conserving, and (ii) the modelled sea level will not be an equipotential surface of Earth’s total gravity field. We force closure of the global water budget by allowing the ‘‘passive’’ ocean to change in mass. This medium-term passive ocean response will not be a uniform change in non- steric ocean surface height, but must necessarily be spatially variable to keep the ‘‘passive’’ ocean surface on an equipotential. Using existing load models, we demonstrate the effects of our consistency theory. Geocenter motion is amplified significantly, by up to 43%.
Disciplines :
Earth sciences & physical geography Physics
Identifiers :
UNILU:UL-ARTICLE-2008-944
Author, co-author :
Clarke, Peter J.; School of Civil Engineering and Geosciences, University of Newcastle
Lavallée, David A.; School of Civil Engineering and Geosciences, University of Newcastle
Blewitt, Geoffrey; School of Civil Engineering and Geosciences, University of Newcastle
Wahr, J. M.; Department of Physics and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado
van Dam, Tonie ; European Center for Geodynamics and Seismology, Walferdange, Luxembourg
Language :
English
Title :
Effect of gravitational consistency and mass conservation on seasonal surface mass loading models