Radar probing of organic slicks on the sea surface

Field experiments on remote sensing of organic slicks on the sea surface are carried out using Ka- and X-band radars, Optical Spectrum Analyzers and C-band ERS-2 SAR. Damping of wind waves due to films of different organic substances is studied in a wide wavelength (from decimeter to millimeter-scale) range, and is shown to be maximal for mm-scale waves. An effect of changing of Ka-band radar Doppler shifts in slicks is revealed in the experiments, the Doppler shift changes are shown to depend strongly on the film elasticity. Physical mechanisms and simple theoretical models of the effects of films on short wind waves are discussed.