Radar sensing of the ocean

Radar remote sensing of the ocean has been the subject of research for about 20 years. Spaceborne radar altimetry and scatterometry are approaching maturity, and synthetic-aperture radars (SAR) show great promise. The principles of radar scattering from the sea are outlined here, along with some recently discovered questions. For wind-vector scatterometry, the principle is presented, and remaining uncertainties are outlined. Principles of SAR imaging of moving targets, and particularly the ocean surface, are outlined. The theory of SAR wave imaging is the subject of considerable controversy, and some principles that can be used in evaluating the various theories are presented, along with brief outlines of the major conflicting theories. Other uses of SAR images are discussed briefly, with a theory to explain the bathymetric expression outlined.