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星载散射计测量的归一化后向散射截面是有关海面毛细重力波的大小和方向的函数:散射计的回波强度与海面毛细重力波的振幅成正比;风向对后向散射系数具有调制作用。因此,可以利用散射计的数据,根据地球物理模型反演出具有高精确度、无雨和中低风速条件下的海面风场矢量。然而高达10%的散射计测量数据会受到降雨影响(Nie,etal.,2008),尤其工作在Ku波段的散射计。降雨对海面散射幅度的影响主要包括:(1)降雨对雷达波的衰减和散射;(2)降雨改变海洋水面形态和海面粗糙度。
The normalized backscatter cross section measured by the spaceborne scatterometer is a function of the size and direction of the capillary gravity waves on the sea surface: the echo intensity of the scatterometer is proportional to the amplitude of the capillary waves of the sea surface; the direction of the wind has a modulation of the backscatter coefficient effect. Therefore, the data of the scatterometer can be used to derive the sea surface wind vector with high accuracy, no rainfall and medium-low wind speed according to the geophysical model. However, up to 10% of scatterometer measurements can be affected by rainfall (Nie et al., 2008), especially in Ku-band scatterometers. The effects of rainfall on the scattering range of the sea surface mainly include: (1) attenuation and scattering of radar waves by rainfall; (2) rainfall changes the shape of ocean surface and sea surface roughness.