Global Marine Gravity and Mean Sea Surface from Multi Mission Satellite Altimetry
Satellite altimetry from the GEOSAT and the ERS-1 geodetic missions provide altimeter data with a very dense coverage. Hence, the gravity field may be recovered very detailed. Satellite altimetry from the 35 days repeat cycle mission of the ERS satellites and, especially, from the 10 days repeat cycle TOPEX/POSEIDON satellite mission provide accurate mean sea surface heights along the ground tracks of those missions. In this study the global marine gravity field has been derived using the altimetry from the geodetic missions. This was done in small cells covering the worlds ocean using advanced techniques for crossover adjustment, gridding by local collocation, and conversion of sea surface heights into gravity by FFT. Then averaged sea surface heights of the repeat missions were used to construct an accurate mean sea surface. To enhance the resolution of the mean sea surface the altimetry from the geodetic missions was utilized. Marine geoid heights derived from the altimetric gravity was used for this task. The advantage of such a procedure is that inconsistences along the edges of the small cells may be avoided.
KeywordsGravity Field Satellite Altimetry Altimeter Data Spherical Harmonic Expansion Geoid Undulation
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