Comparison ofin situ and remotely sensed ocean waves off Marineland, Florida

Abstract

Some early results from an oceanographic experiment staged off Marineland, Florida, in December 1975 are presented, viz., intercomparisons between the X-band and L-band imagery obtained by the Environmental Research Institute of Michigan's (ERIM) dual-wavelength, dualpolarization multiplexed radar. This radar allows direct comparison since the images are produced simultaneously. The wave data obtained from the radar imagery are compared with surface measurements of waves obtained with a pitch- and-roll buoy. The conclusions are only applicable to medium and low wind and wave conditions encountered during the Marineland test. The results indicate that X-band images provide superior quality wave imagery and more useful Fourier Transforms compared to L-band under equivalent signal-to-noise ratios and resolution. Optimum wave imagery is seen when waves propagate in the range direction. Comparisons betweenin situ measurements and X-band imagery of the same area indicate that the dominant wave direction can be obtained from imagery to within a few degrees. A one-dimensional spectrum obtained from X-band imagery compares favorably with an equivalent wave frequency spectrum obtained from the pitch- and-roll buoy after suitable transformation asing linear wave theory.