Model used in the simulation: Navy Coastal Ocean Model (NCOM) with 1 sigma layer
Model domain: barotropic ocean over a long shelf (1100 km) on the f-plane. The coast is at the right (eastern) side. The shelf is 200 km wide at the 100m isobath, with a shelf break (from 200 to 400 km) and a flat bottom (400 to 500 km). The bathymetry is shown in figure wind_topogr.jpg.

The model is forced with a cyclonic wind stress calculated from an analytical wind (wind speed profile is shown in the figure wind_topogr.jpg). The center of the hurricane is placed at ~430 km off the coast. The hurricane is translated northward with a speed of 20 km/hour along the shelf (from bottom to top in the movie).

In the movie (hurr20.mov), sea surface height (in meters) is shown with superimposed wind velocity vectors. Southerly wind near the coast generates a high SSH anomaly which propagates northward as a barotropic wave. Since the hurricane is moving in the same direction as the wave propagation, the SSH anomaly is amplified (up to 70 cm in this experiment) as it travels northward along the coast.

From the preliminary analysis of scatterometer data, the wind speed over the shelf region used in the simulation (less than 20 m/s) is lower than that experienced with Hurricane Dennis. Therefore one might expect a larger SSH anomaly at the wave crest (> 1 m). Simulation of the West Florida Shelf dynamics during hurricane Dennis using NCOM with realistic forcing and baroclinic ocean is in progress. Also, a sensitivity study of the dependence of the shelf wave on the translation speed of the hurricane will be conducted.

D.S. Dukhovskoy
S.L. Morey