SEASONAL MODULATION OF THE WEST FLORIDA CONTINENTAL-SHELF CIRCULATION

Velocity data from 28 degrees N, 84 degrees W on the west Florida cont inental shelf are presented. The data were sampled from October 1993 t hrough January 1995 at 1 m intervals between 3 m and 42 m in a total w ater depth of 47 m. Their monthly means suggest an annual cycle hypoth esized to be driven by a seasonally varying shelf-wide baroclinic stru cture. Motions at semi-diurnal, diurnal and synoptic time scales are s easonally modulated, both by wind forcing and stratification that deco uples fluid motions from the damping effects of bottom friction. These motions are presented in the form of progressive vector plots. With 1 6 months of data, probability density and distribution functions for a long-shore and across-shore particle displacements over specific time intervals are constructed. For daily intervals, particles are equally likely to travel approximately 5 km (depending upon confidence interva l) in any direction. For monthly intervals, particles may travel a few hundred km, primarily along-shore.