Detection of ocean wave groupiness from spaceborne synthetic aperture radar
Detection of ocean wave groupiness from spaceborne synthetic aperture radar
复制标题
星载合成孔径雷达海浪群性检测
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
J. Schulz
中科院分区：
文献类型：
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作者：
J. C. N. Borge;S. Lehner;A. Niedermeier;J. Schulz
[1][1]近年来，一些能够提供海面二维信息的遥感技术已被应用于描述海况。该信息是从方向波数谱的估计中获得的。然而，波数谱不足以完整地描述海况。对一些现象的分析，如波的分组、单个波的检测、最大波高等，需要一个补充研究，这是历史上根据浮标记录在时间域进行的研究。在两个维度(例如，空间域)中，可以在空间域而不是时间域中对这些现象进行互补分析。本文提出了两种从海面图像分析波群性的方法：一种是基于二维推广的平滑瞬时波能历史(SIWEH)函数，该函数最初是为了分析波高时间序列的波群性而开发的。第二种方法利用二维波包估计来提取波群参数。假设波场为高斯随机过程，将这两种方法应用于ERS-2合成孔径雷达(SAR)和ENVISAT高级合成孔径雷达(ASAR)海面图像，只考虑近程行波的情况，以避免SAR成像机制中的强非线性。结果表明，星载合成孔径雷达可用于提取全球尺度的波群信息。
[1] In recent years a number of remote sensing techniques capable to provide two-dimensional information of the sea surface have been applied to describe sea states. This information is obtained from the estimation of the directional wave number spectrum. However, the wave number spectrum is not sufficient for a complete description of sea states. The analysis of some phenomena such as wave grouping, detection of individual waves, maximum wave heights, etc., needs a complementary study, which has been carried out historically in the temporal domain from buoy records. In two dimensions (e.g., the spatial domain), the complementary analysis of those phenomena can be carried out in the spatial domain rather than the temporal domain. In this work, two methods to analyze wave groupiness in the spatial domain from sea surface images are presented: The first method is based on the two-dimensional generalization of the Smoothed Instantaneous Wave Energy History (SIWEH) function, which had been originally developed to analyze wave groupiness for wave elevation time series. The second method uses the estimation of the wave envelope in two dimensions to extract wave grouping parameters. Assuming that the wave fields are Gaussian stochastic processes, both methods are applied to ERS-2 synthetic aperture radar (SAR) and ENVISAT advanced SAR (ASAR) images of the sea surface, where only cases with almost range traveling waves are considered in order to avoid strong nonlinearities in the SAR imaging mechanisms. The obtained results shown that spaceborne SAR can be used to extract wave grouping information on global scale.