利用双波段补偿法提高卫星高度计海面风速反演精度

Using A Dual\|Frequency Adjustment Approach to Improve the Accuracy of Altimeter Retrieved Sea Surface Wind Speed

提出了一种利用卫星高度计测量的同步双波段雷达散射截面数据（σ０Ｋｕ 和σ０Ｃ）提取海面风速特别是高风速信息的补偿算法。这一方法的基本思想是假定在正常情况下，高度计测量的Ｋｕ 和Ｃ波段的后向散射截面对于某一风速存在一种“标准”关系，降雨和大浪等异常大气海洋过程的出现会导致σ０Ｋｕ ／σ０Ｃ 偏离其“标准”位置而产生一个系统误差，通过对这一系统误差进行修正和补偿，可以有效地消除其影响并显著提高高度计海面风速的反演精度。实验表明，与通常采用的单波段海面风速反演算法相比，双波段补偿法可提高精度１０％ 左右。

Based on simultaneous measurements of Ku and C bands' radar cross sections ( σ 0 Ku and σ 0 C) from satellite altimetry, this paper proposes a dual\|frequency approach to enhance the performance of existing wind speed algorithms, especially at high wind speeds. A simple scheme of σ 0 Ku /σ 0 C adjustment is developed, assuming that altimeter measured radar cross sections of Ku and C bands follow a “standard” relationship for various wind speeds under normal conditions. Rain and significant wave height(SWH) induced systematic deviations of σ 0 Ku /σ 0 C with respect to their “standard” positions are observed and corrected using the proposed scheme. Validation of our results against buoy observations suggests that the dual\|frequency scheme improves the accuracy of altimeter measured sea surface wind speeds by nearly 10% compared to single frequency algorithms.