Extreme Southern Ocean Tide Modeling

Abstract

Predictability of barotropic ocean tides is significantly less accurate in the coastal regions, littoral and shallow seas, and oceans not covered by TOPEX/POSEIDON (T/P) than in deep oceans (>1000 m depth) within ±66° latitude. Barotropic ocean tide models (mostly with spatial resolutions at 50 km or longer), benefited primarily from T/P altimetry and hydrodynamic modeling, allow predictions of deep ocean tidal amplitudes with an estimated accuracy of 1-2 cm (1 σ). Even with the availability of most recent suite of available global tide models based primarily on T/P data, e.g., GOT00, NA099, Delft, FESOO, extreme Southern Ocean tides below 60S are limited both in accuracy and resolutions, especially in regions near Antarctica where parts of ocean surfaces are seasonally or permanently covered with ice. In our initial study with the objectives to improve tides in Antarctic 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, regional models such as the Padman models (Weddell Sea and Ross Sea) are currently available. Test models below 50S are presented using available T/P and ERS-2 altimeter data over ocean surfaces as well as retracked ERS-2 data over sea surfaces covered with ice.