O. Eisen
Alfred-Wegener-Institut für Polar- und Meeresforschung, Bremerhaven

Ch. Kottmeier
Institut für Meteorologie und Klimaforschung, Universität Karlsruhe/Forschungszentrum, Karlsruhe

Laurie Padman
Earth and Space Research, Seattle, WA 98102-3620

P. Lemke
Alfred-Wegener-Institut f¨ur Polar- und Meeresforschung, Bremerhaven

The effects of tides on the seasonal fluctuation and regional differences of sea-ice cover in the Weddell Sea are investigated using an improved dynamic-thermodynamic sea-ice model. Tidal currents are calculated using an 8-constituent barotropic, ocean only, tidal model. Tidal currents add a highly variable stress force at the ice-water interface. Results from runs of the sea-ice model with and without this additional stress demonstrate that tidal currents alter the local and, to lesser extent, basin-wide evolution of sea ice. The tidal currents reduce the expansion of the ice cover, mostly cause a speed up of the retreat, and lead to smaller minimum ice extent. The most significant local differences between the two models are found in tidally active regions over the continental shelf breaks of the western Weddell Sea, in front of Filchner-Ronne Ice Shelf, and offshore Dronning Maud Land.