Title :
Incoherent bistatic scattering from the sea surface at L-band
Author :
Fung, Adrian K. ; Zuffada, Cinzia ; Hsieh, C.-Y.
Author_Institution :
Wave Scattering Res. Center, Texas Univ., Arlington, TX, USA
fDate :
5/1/2001 12:00:00 AM
Abstract :
A bistatic electromagnetic wave scattering model for the sea surface is developed to examine its wind dependence property over a wide range of incident angles along the specular direction. This is done by combining an existing scattering model with a sea spectrum recently reported in the literature. In general, electromagnetic wave scattering from a rough surface is dependent on the Fourier transform of the nth power of its height correlation function which can be computed numerically from the surface spectrum. This transform relation indicates that scattering is sensitive not only to the surface spectrum but also to its convoluted properties. Generally, surface scattering is sensitive only to a portion of the surface correlation measured from the origin. The size of this portion is a function of three variables (the incident angle, the surface height standard deviation, and the exploring wavelength) and the rate of decay of the correlation function. The decay rate near the origin of the sea surface correlation is very small, so much so that at L-band this portion is too wide for a two-term approximation of the correlation function. This is true in spite of the fact that the sea surface has a very large rms height. Thus, a scattering model based on geometric optics is generally not applicable at L-band especially at large angles of incidence. An additional finding is that in specular scattering wind dependence is stronger at larger angles of incidence for incident angles between 0 and 70° over the wind speed range of 4 m/s-20 m/s
Keywords :
atmospheric techniques; meteorological radar; oceanographic techniques; radar cross-sections; radar theory; remote sensing by radar; wind; Fourier transform; L-band; UHF; electromagnetic wave scattering model; geometric optics; height correlation function; incidence angle; incoherent bistatic scattering; marine atmosphere; meteorology; model; ocean wave; radar remote sensing; radar scattering; rough surface; sea surface; specular direction; specular scattering; wind speed; Electromagnetic modeling; Electromagnetic scattering; Fourier transforms; L-band; Optical scattering; Optical surface waves; Rough surfaces; Sea surface; Surface roughness; Surface waves;
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on