Development Sea Surface Measurement Technique by Using Microwave Scatterometer

本研究的目的是研究风、浪和流共存的水面上的微波散射特性，并提出主动微波遥感海面测量技术。首先，在一个实验水箱中，利用已知的风、流和波浪生成人工水面，并详细研究了风、流和波对水面微波散射的影响。在此基础上，发展了表面流法微波散射的数值模拟技术，用来评价复杂海面的微波散射特性，并通过数值模拟研究了海面的微波散射特性。结果表明：1)微波的后向散射强度仅与风速有关，2)后向散射微波的多普勒谱的中频取决于风速和流速。3)后向散射微波的多普勒谱的带宽取决于波的轨道速度(水颗粒在水面上的漂移速度)。这些结果证实了前人的研究结果，明确了多普勒谱与风或浪的关系。在此基础上，进一步明确了利用主动微波遥感进行海面测量的途径。

The purpose of this research were the investigation of the microwave scattering characteristics on water surfaces which coexists wind, waves and currents, and the proposal of the sea surface measurement technique by active microwave remote sensing.First, we generated artificial water surfaces by known wind, currents and waves in an experimental water tank, and we examined the effects of wind, currents and waves on microwave scattering at that surface in detail. Then numerical simulation technique of microwave scattering on the water surface by surface current method was developed to evaluate microwave scattering in the real surface of the sea of more complicated shape, and microwave scattering characteristic at the surface of the sea by the numerical simulation was examined.As the result, some back scattering characteristics of microwaves on water surface in the following have been obtained.1)The back scattering strength depends on only the wind velocity, and no effects of currents and waves were.2)The middle frequency of Doppler spectrum of backscattering microwaves depends on the wind and current velocities.3)The band width of Doppler spectrum of back scattering microwaves depends on orbital velocity (drift speed of water particle in the surface of the water) of a wave.By these results, the previous researches have been confirmed, and the relations between Doppler spectrum and wind or waves were cleared. Further, on the basis of these results, the way to the sea surface measurement by active microwave remote sensing has been showed clearly.