Surf zone surface displacement measurements using interferometric microwave radar

Vertically polarized backscattered power, Doppler velocity, and interferometric height were measured in the nearshore ocean region using a high-resolution imaging microwave radar. The interferometric surface displacement measurements are compared with normalized radar cross sections (NRCS) and Doppler velocities, and with in situ pressure sensor estimates of wave height. The rms uncertainty in the interferometric surface displacement is computed from the data. The interferometric surface displacement measurements are intuitively satisfying in that positive displacements are generally associated with pixels that have larger NRCS values. Interferometric surface displacements compare well with heights derived from in situ pressure sensors, and we provide some possible explanations for the differences.