Assessment of Geoid Models Offshore Western AustraliaUsing In-Situ Measurements

摘要

In Western Australia, coastal dynamics are influenced by a major ocean boundary current system, the LeeuwinCurrent, which is characterised by mesoscale features. To fully understand the Leeuwin Current using satellite al-timeter measurements, we must have a precise (1-2 cm) and full-spatial-scale (<100 km) geoid model. This paperfocuses on a comparison between two mean dynamic ocean topography models derived from independent hydrographicclimatologies, and an altimeter-observed mean sea surface referenced to recently released geoid models offshore ofWestern Australia (20°S to 45°S, 108°E to 130°E). The geoid models used include combined global geopotential modelsfrom the GRACE satellite mission and AUSGeoid98. The estimated mean dynamic ocean topography models arecompared with independent dynamic ocean topography from CSIRO's Atlas of Regional Seas (CARS) climatology. Theresults show that the EIGEN_GLO4C and GGMO2C + EGM96 global geopotential models to degree and order 360give the best comparisons against CARS in the Leeuwin Current region, suggesting that they should be used in thefuture for computing ocean transport, surface current velocities, and dynamic topography, and be used as a referencefield for future computations of regional marine geoid models.