OGE12, A New 360 Gravity Field Model

Abstract

A new high resolution Earth gravity field model with harmonic coefficients complete to degree and order 360 is presented. As in an earlier solution, a-priori information is taken from the GRIM4 gravity field (complete to degree and order 50). High frequency determination is based on both, surface gravity and ocean geoid heights. Surface gravity is corrected for topographic and atmospheric effects. Ocean geoid heights were derived from a one year mean sea surface height model determined from Geosat altimetry and corrected for sea surface topography and permanent tidal deformation. The estimation of the 360 field is based on a rigorous least squares harmonic analysis. With globally distributed, equally spaced data sets, the normal equation system decomposes to block diagonal structure. Undefined data are successively substituted by block mean values from intermediate results. Data preparation and weighting scheme of a-priori information and surface data have been improved for the present solution.