Observations of ocean surface disturbances using high-resolution passive microwave imaging

The airborne multichannel Polarimetric Scanning Radiometer (PSR) was used to obtain high-resolution images of the ocean surface at nadir incidence angles of 65° and 58° and five frequencies: 10.7, 18.7, 21.3, 37.0, 89.0 GHz. Both vertical and horizontal polarizations were measured simultaneously at resolutions of ~1.1 km and 320 m. The experiments were conducted in 1997-1998 from the NASA P-3B and DC-8 aircraft over moderately stable conditions. Upon rendering and filtering it was found that the PSR images consist of a mosaic of “hot” and “cold” ocean thermal emission features. Some distinct radiometric signatures of specific texture, shape and size were detected in the mosaic. We hypothesize that these geometrical radiometric features are associated with hydrodynamic disturbances among which natural ocean surface slicks, wind inhomogeneities, and current boundaries are the most probable causes. Textures of PSR ocean surface images and observed radiometric signatures are described in this paper