Ross Tide Modeling Using INSAR and Radar Altimetry

Ocean tides play a significant role in the complex interactions between the atmosphere, ocean, sea ice and floating glacial ice shelves. Tidal currents create turbulent mixing at the bottom of the ice shelf contributing to the creation of rifts for the possible detachment of part of the ice bergs and can influence heat transport between the ice shelf and sea water. Tides near and under floating ice shelves and sea ice, and depending on surface and basal slopes, grounding line migrates with time within a grounding zone. Improved knowledge of the grounding line is inherently necessary to study ice mass balance and its contribution to the global sea level change. Even with the availability of most recent suite of global tide models based primarily on TOPEX/POSEIDON data, e.g., GOT00, NAO99, Delft, FES00, extreme southern ocean tides (-60 deg. latitude South pole-ward) are limited both in accuracy and resolutions, especially in regions near Antarctica, seasonally or permanently sea-ice-covered oceans. InSAR tidal deformation analysis using ERS-1/-2 tandem missions over Ross Sea and in a test region over the Sulzberger Ice Shelf, Ross Sea (-77.50 latitude, 1500 East Longitude) will be presented. In our initial study with the objectives to improve tides in Antarctica oceans for accurate prediction of ground-line locations to enhance ice mass balance studies, we provide an assessment of accuracy of tide models in the region. In addition to global models, finer resolution regional models in the Antarctica Ocean such as the Padman model are available. Coarse resolution tide models using (-50 deg latitude South pole-ward) using available over-ocean and over sea ice and ice-shelf data from ERS-1 and ERS-2, and GFO, will be presented. A fine-resolution test ocean tide model using combined radar altimeter and ERS tandem mission InSAR data over the Sulzberger Ice Shelf is described.