The two-scale radar wave probe and SAR imagery of the ocean

A two-scale formulation of oceanic backscatter of microwave radiation, which has previously been applied to the dual-frequency scatterometer, is applied here to the two-scale radar wave probe and SAR imagery of the ocean. A two-scale radar wave probe is a microwave system which coherently detects signals scattered from a very small patch of the ocean surface. It is shown that a SAR image may be described as a convolution of the AM part of the output of a two-scale wave probe with the power spectrum of the FM part of the output. Thus SAR images are not faithful reproductions of cross-section variations over the surface. Distortions occur as a result of variable surface velocities. Examples of this distortion are derived from two-scale wave probe data taken in the Gulf of Mexico. Application of a focusing correction does not remove the distortion from the simulated image of a nearly sinusoidal, azimuth-traveling wave. Large V/R0 ratios minimize the distortion, however.

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