S band Doppler radar measurements of bathymetry, wave energy fluxes, and dissipation across an offshore bar

The use of a shore-based microwave Doppler radar for the remote sensing of ocean wave propagation over an offshore sand bar was investigated. The radar yielded high spatial resolution measurements of several quantities of importance in the study of bar dynamics. The spatial variation in wave phase with distance along the radar beam direction was used to calculate bathymetry with sufficient accuracy and resolution to clearly reveal the presence of the bar and the tidal cycle variation of water depth. This real-time bathymetry enabled the calculation of ocean wave energy fluxes from the radar velocity data. These energy fluxes showed good agreement with predictions from a numerical wave propagation model, except in regions of significant wave breaking, where the discrepancy between measured and modeled fluxes was found to be closely related to the modeled wave dissipation rate.

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