Advances in Southern Ocean tide modeling

Tides in the polar region play a major role in the dynamics of sea ice and floating glacial ice shelves. Existing ocean tide models are much less accurate in coastal and shallow seas and polar oceans than other ocean areas. In particular, ocean tides are largely unknown in parts of polar oceans that are covered by permanent or seasonal sea ice and in regions that are beyond the coverage of the TOPEX/POSEIDON (T/P). We conducted a periodogram analysis using simulated satellite altimeter data (T/P or JASON, ERS-2 or ENVISAT) at single and dual satellite crossover locations. Our results indicate that the TOPEX/ERS-2 dual satellite crossovers show considerable improvements to mitigate tidal aliasing and are, therefore, preferable for tidal modeling. Empirical ocean tide models have been determined using the T/P and ERS-2 altimetry at crossovers in the Southern Ocean below 55°S and employing the response method. Evaluations using in situ pelagic tidal constants and altimeter data indicate that the resulting empirical tide models are as good as the selected contemporary models (NAO.99b, TPXO.6.2, and CATS02.01) in the Southern Ocean. Solutions for the M2, O1, N2, and Q1 tides that are obtained from the ERS-2 data only show a reasonable accuracy, indicating that extensions of the tide modeling domain beyond the T/P coverage are feasible.