Free air gravity anomalies over the oceans from Seasat and GEOS 3 altimeter data



Satellite altimetry measurements have been used extensively in the last few years to compute local or global grids of values of geoid heights with respect to a given reference ellipsoid [see Balmino et al., 1979; Marsh and Martin, 1982; Marsh et al., 1982; Marsh et al., 1984[. Such grids have different spacings in latitude and longitude, with the typical step size of 0.5°×0.5°. The grids have been used for a variety of applications [Lazarewicz and Schwank, 1982], especially for correlating the high- and medium-frequency part of the gravity field with bathymetry [e.g., Cazenave et al., 1983[. Equal-angular 1°×1° mean free air gravity anomalies have also been derived, generally by collocation [Rapp, 1979, 1983a,b], and used in global geopotential models in spherical harmonics [Reigber et al., 1985].