Simulation Study on the Effect of Wind on SAR Imaging of Shallow Water Bathymetry
风速风向对SAR浅海水下地形成像影响的仿真研究

A smi ulationmodel ofSAR mi aging of shallow water bathymetry has been developed based on SAR mi aging mechanism of shallow water bathymetry and the microwave radar mi aging of oceanic surface s program ofM4S. This smi ulationmodel mi proves the drawback of the traditional smi ulation mode,l which just only smi ulated alternant dark bright streaks, and both streakshave almost the same relative radarbackscatter, butcould notsmi ulate streaks in the form ofdark streaks orbright streaks respectively. However, above three expressions appear in shallowwater bathymetry SAR mi ages mi aging at the same area and the same local tmi e in each one day. As far aswe known, SAR can t mi age shallow water bathymetry featuresdirectly. It mi ages the bathymetry via surface effects induced by tidalcurrents flow variation over bottom topography under favorable currents and sea surfacewinds, thus the form of shallowwaterbathymetry SAR mi ages has close relationship with hydrological and meteorological conditions. Herein, we give the SAR smi ulation process of shallowwater bathymetry according to SAR mi aging mechanism of shallow water bathymetry, and make use of this mi proved smi ulation mode,l carry out the smi ulation study on the effect of wind on SAR mi aging of shallow water bathymetry. Also the relationship between the sea surface wind and SAR mi aging of shallow water bathymetry has been analyzed using both the results of the smi ulation and the analysis of shallowwater bathymetry SAR mi ages. According to these results, the relationship between the sea surface winds and SAR mi aging of shallow water bathymetry has been strengthened, which shows that, under lower wind speed, the SAR backscattering cross section of the sea surface of shallowwaterbathymetry is darker, vice versa. The relative intensity of the brightand dark streaks is also affected by the wind speed but is not themain factor. The effect ofwind direction on SAR mi aging of shallow water bathymetry ismore mi portant. When thewind direction is adverse or to parallel the direction of currents component in direction of shallow waterbathymetry, the SAR backscattering cross section of the sea surface is brighter, bright streaks and dark streaks appear on SAR mi ages respectively. Under crosswind, the SAR backscattering cross section of the sea surface is darker, the bright and dark streaks are alternant, and the adverse wind direction is better for SAR mi aging of shallow water bathymetry. In this study, we fully analyze the expression of shallow water bathymetry SAR mi ages under different sea surfacewind speeds and directions, which is an necessary step for extracting quantitative information of shallow water bathymetry form SAR mi ages.