Scatterometer azimuthal response and wind wave directionalityAzimuthal response of a scatterometer to radiation scattered by the sea surface was studied in a wind-wave tank. The variation of the normalized radar cross section with the azimuth angle is fitted by a three-term series. Results show that the upwind-downwind asymmetry decreases as the wind speed increases. The crosswind modulation depends on the wind velocity. The results show that the evolution of the long-wind-crosswind ratio evolves with wind speed in a manner similar to the evolution of the isotropy of short capillary-gravity waves. The maximum of the isotropy of the short wind waves is obtained for wind velocities close to 4 m/s. For the same value of the velocity, the variations of radar response between long-wind and crosswind directions is minimum. For lower or higher values of wind velocities the directional accuracy of the radar increases, since the wind-wave field tends to align in the wind direction.
Document ID
19910031144
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Giovanangeli, J. P. (Aix-Marseilles Univ. France)
Le Calve, O. (Institut de Mecanique Statistique de la Turbulence Marseille, France)
Bliven, L. (NASA Wallops Flight Center Wallops Island, VA, United States)