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面元匹配是散射计海面风场反演的重要预处理步骤。为保障海洋二号卫星散射计(HSCAT)业务化海面风场反演,提出了一种可业务化运行的HSCAT面元匹配算法。HSCAT面元匹配算法包括地面网格划分和后向散射系数观测结果重采样两个关键部分。为简化计算,HSCAT采用以星下点轨迹为中心,以顺轨向及交轨向为坐标轴,分辨率为25 km×25 km的网格划分方式。重采样利用卫星星下点经纬度数据,对每个后向散射系数观测结果,以后向散射系数与各星下点球面距离的最小值为依据进行交轨向重采样,并以取得距离最小值所对应的星下点与该轨数据星下点起始位置的距离为依据进行顺轨向重采样,实现对后向散射系数观测结果的面元匹配。实验和对比结果表明,提出的面元匹配算法可对后向散射系数进行有效的重采样,风矢量面元的位置分布均匀,每个风矢量面元均有足够数量的独立观测后向散射系数,可在全球范围内满足高质量海面风场反演的要求。
Matching bouncing is an important pretreatment step for the wind field inversion of scatterometer. In order to ensure the HSCAT operational sea surface wind inversion, a HSCAT facet matching algorithm which can be operated in operation is proposed. The HSCAT facet matching algorithm consists of two key parts: ground meshing and rescanning of the backscattering coefficient observations. In order to simplify the calculation, HSCAT uses a meshing method centered on the trajectory of the satellite, with a coordinate of 25 km × 25 km in the direction of the orbit and the orbit. Resampling uses the latitude and longitude data of the satellite under the point, the backscattering coefficient for each observation results, and later the scattering coefficient and the subsurface spherical minimum distance based on the orbit re-sampling, and to obtain the minimum distance The corresponding sub-satellite point and the orbit of the satellite data from the starting point of the starting position based on the number of resampling, to achieve the backscattering coefficient observation results of the bin matching. Experiments and comparison results show that the proposed face-matching algorithm can effectively resample the backscattering coefficients, the location of the wind vector bins is uniform, and each wind vector bin has a sufficient number of independent observed backscatter coefficients , Which can meet the requirements of high-quality retrieval of sea surface wind field in the world.