Radar Remote Sensing Estimates of Waves and Wave Forcing at a Tidal Inlet

Guillermo M. Díaz Méndez, Merrick C. Haller, Britt Raubenheimer, Steve Elgar, David A. Honegger
2015 Journal of Atmospheric and Oceanic Technology  
The time and space variability of wave transformation through a tidal inlet is investigated with radar remote sensing. The frequency of wave breaking and the net wave breaking dissipation at high spatial resolution is estimated using image sequences acquired with a land-based X-band marine radar. Using the radar intensity data, transformed to normalized radar cross section s 0 , the temporal and spatial distributions of wave breaking are identified using a threshold developed via the data
more » ... ility density function. In addition, the inlet bathymetry is determined via depth inversion of the radar-derived frequencies and wavenumbers of the surface waves using a preexisting algorithm (cBathy). Wave height transformation is calculated through the 1D cross-shore energy flux equation incorporating the radar-estimated breaking distribution and bathymetry. The accuracy of the methodology is tested by comparison with in situ wave height observations over a 9-day period, obtaining correlation values R 5 0.68 to 0.96, and root-mean-square errors from 0.05 to 0.19 m. Predicted wave forcing, computed as the along-inlet gradient of the cross-shore radiation stress ›S xx /›x was onshore during high-wave conditions, in good agreement (R 5 0.95) with observations.
doi:10.1175/jtech-d-14-00215.1 fatcat:ybgsnitxwrcotg3ft2ad4gu3ke