Abstract

Ocean Tides in the Ross Sea and Under the Ross Ice Shelf

We describe a data assimilation model for ocean tides in the Ross Sea. Our work is motivated by the need to accurately model sea surface height (SSH) in the ocean cavity under the Ross Ice Shelf (RIS) so that tides can be removed from satellite-based measurements of ice shelf vertical motion to reveal changes over long time scales. Tides are also responsible for much of the ocean kinetic energy that causes mixing under the RIS, and also along the shelf break where dense water is formed at the Antarctic Slope Front. (Along the shelf break in the northwestern Ross Sea, predicted tidal currents sometimes exceed 100 cm s^-1.) The data that are assimilated include TOPEX/Poseidon satellite altimetry (north of ~66^oS), tide gauges, gravimetric records on the RIS, and current meters. The model is validated with additional current meters and gravimetric records, and hull-mounted acoustic Doppler current profilers (ADCPs). We demonstrate the effect of data assimilation by comparing our results with predictions from a standard (non-assimilative) ocean model of circum-Antarctic tides.