Acta Scientiarum Naturalium Universitatis Pekinensis

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Research on Ocean Surface Wind Ambiguity Removal Algorithm for SeaWinds Scatterometer

XIE Xuetong1, 2, FANG Yu1, CHEN Kehai2, CHEN Xiaoxiang2   

  • Received:2004-10-15 Online:2005-11-20 Published:2005-11-20



Abstract: The Maximum Likelihood Estimation (MLE) algorithm for SeaWinds scatterometer wind vector retrieval generates 2~4 wind vector ambiguities, so a circle median filter is needed to perform the ambiguity removal. According to the spatial distribution characteristic of the most likely ambiguities in each SeaWinds wind vector cell, a new method for SeaWinds ambiguity removal is derived and discussed theoretically for its adaptability. This method features simple definition for the circle median number, low computation and easiness to converge. Using some L2A raw data from NASA to validate our method, the results indicate that under simple wind distribution condition the new method is effective in resolving the problem of block ambiguity appearing on each edge area of SeaWinds swath without any other reference data to initialize the wind field.

Key words: SeaWinds, wind retrieval, circle median filter, block ambiguity

摘要: 利用最大似然法(MLE)对SeaWinds散射计数据反演得出的风矢量,一般存在2~4个模糊解,故需采用圆中数滤波法进行模糊去除。根据SeaWinds散射计第一模糊解的空间分布特性,归纳出一套适合SeaWinds散射计的模糊去除方法,并在理论上探讨了其适应性。该方法的圆中数定义简单,计算量小,且易于收敛。利用美国NASA提供的部分L2A原始数据对该方法进行验证的结果表明,对于简单风场分布情况,该方法在没有其他参考数据进行初始化的条件下,能有效解决SeaWinds轨道边缘区域的块状模糊问题。

关键词: SeaWinds, 风场反演, 圆中数滤波, 块状模糊

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