The effect of ocean tidal loading on satellite altimetry over Antarctica

Vertical displacements of emerged land caused by oceanic tidal loading are of the order of several tens of millimetres in polar regions. They constitu te a long wavelength signal, the amplitude of which is comparable to elevat ion changes that might be associated with climate-driven changes in ice-she et volume. Using bilinear interpolation on a 1 degrees by 10 global grid, w e examine the amplitudes and phases of vertical displacements caused at any given epoch by the eight most important ocean tide constituents of recent ocean tide models, extrapolated to high latitudes. This permits estimation of the oceanic tidal loading corrections to measurements made by a satellit e altimeter along the satellite ground track. We have done so systematicall y over Antarctica, for a scenario flight of ICESAT, which carries the Geosc ience Laser Altimeter System (GLAS), whose primary science goal is to monit or ice-sheet mass balance. Ocean loading tide corrections near the coast of Antarctica can reach several centimetres; overall they average about 10 mm .