Open AccessNontidal oceanic contributions to gravitational field changes: Predictions of the Parallel Ocean Climate Model
Author(s) -
Johnson Thomas J.,
Wilson Clark R.,
Chao Benjamin F.
Publication year - 2001
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000jb900438
Subject(s) - gravitational field , atmosphere (unit) , satellite , gravitation , ocean current , physics , climatology , environmental science , climate model , field (mathematics) , atmospheric sciences , geodesy , geophysics , geology , meteorology , climate change , oceanography , classical mechanics , mathematics , astronomy , pure mathematics
This study examines the nontidal contributions of the oceans to the Earth's gravitational field variations as predicted by a global ocean general circulation model: the Parallel Ocean Climate Model. Such variations in the gravitational field Stokes coefficient are determined up to spherical harmonic degree and order 20 and compared with satellite laser ranging (SLR) data from LAGEOS I and LAGEOS II. For most Stokes coefficients except the lowest‐degree ones, this investigation indicates that the application of sea level adjustment to reduce the effects of the model's lack of mass conservation due to the Boussinesq approximation has a negligible effect on timescales less than a few years. Predicted gravitational changes show strong seasonal variability and account for a portion of the variations estimated from SLR. We conclude that, in addition to the atmosphere, the oceans are an important contributor to the temporal variations in the Earth's gravitational field. The Stokes coefficients are useful in examining oceanic mass transport between hemispheres and ocean basins. The estimated oceanic power spectrum has a spectral shape similar to the atmosphere and is well above the noise level of planned satellite missions like the Gravity Recovery and Climate Experiment (GRACE).