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Oceanic tides from Geosat altimetry

1990; American Geophysical Union; Volume: 95; Issue: C3 Linguagem: Inglês

10.1029/jc095ic03p03069

2156-2202

David E. Cartwright, Richard D. Ray,

Astro and Planetary Science

Direct tidal analysis of the altimetry from the Geosat Exact Repeat Mission's first year is used to derive estimates of the diurnal and semidiurnal oceanic tides. The geoid is removed by collinear differences at 34.1‐day separation, and the orbit error is reduced by subtracting a slowly modulated 1 cycle/revolution term. A sequence of independent analyses at grid areas of 1° latitude×1.5° longitude using “orthotide” functions ensures complete definition of the diurnal and semidiurnal species. Global admittance maps for M 2 and S 2 within the latitudes 58°N and 59°S compare well with ground truth at 66 open‐ocean sites. Maps of differences between Geosat and the Naval Surface Weapons Center model show important areas of the order of 10–15 cm. The integral for the global power input from the moon gives 2.51 TW (M 2 ), 0.44 TW (S 2 ), lower than many previous estimates, but in agreement with figures deduced from a recent analysis of satellite orbits.