Validation of Significant Wave Height From Improved Satellite Altimetry in the German Bight
Validation of Significant Wave Height From Improved Satellite Altimetry in the German Bight
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DOI：
10.1109/tgrs.2014.2356331
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发表时间：
2015-04-01
影响因子：
8.2
通讯作者：
Cipollini, Paolo
中科院分区：
文献类型：
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作者：
Passaro, Marcello;Fenoglio-Marc, Luciana;Cipollini, Paolo
有效波高（SWH）是通过卫星测高绘制全球地图。SWH估计是可能的，因为脉冲限制测高波形的形状取决于海况。SWH的算法还取决于点目标响应（PTR）函数的宽度。对于SWH检测而言，特别具有挑战性的是海岸数据，这是由于高度计足迹中的陆地和平静水域干扰，以及低海况，这是由于波形中的非常尖锐的前沿，因此采样较差。在这里，自适应前沿子波形Retracker（ALES），一种新的算法，用于重新处理测高波形，将验证SWH估计在德国湾。这一具有挑战性的区域同时存在着低海况和沿海问题，可利用Bundesamt fuer Seeschiffahrt und Hydrographie的扩展浮标网络进行现场验证。环境卫星、Jason-1和Jason-2任务的再处理数据与三个近海浮标进行了对比验证。在最靠近浮标的点和沿沿着的所有其他点上进行原位验证。技能指标基于偏差、标准差、回归线斜率和相关性大于90%的循环数。我们还测试了纳入Envisat传感器地球物理数据记录中提供的两个额外波形样本以及采用不同PTR宽度值的影响。结果表明，近岸ALES估计的SWH一般更好地与浮标数据比标准处理的产品。
Significant wave height (SWH) is mapped globally through satellite altimetry. SWH estimation is possible because the shape of a pulse-limited altimetric waveform depends on the sea state. The algorithm for SWH also depends on the width of the point target response (PTR) function. Particularly challenging for SWH detection are coastal data, due to land and calm water interference in the altimeter footprint, and low sea states, due to an extremely sharp leading edge in the waveform that is consequently poorly sampled. Here, Adaptive Leading Edge Subwaveform Retracker (ALES), a new algorithm for reprocessing altimetric waveforms, will be validated for SWH estimation in the German Bight. This challenging region presents both low sea state and coastal issues, and an extended network of buoys of the Bundesamt fuer Seeschiffahrt und Hydrographie is available for the in situ validation. Reprocessed data from Envisat, Jason-1, and Jason-2 missions are validated against the three offshore buoys. The in situ validation is applied both at the point nearest to the buoy and at all other points along track. The skill metrics is based on bias, standard deviation, slope of regression line, and number of cycles with correlation larger than 90%. We also tested the impact of the inclusion of two additional waveform samples that are provided in the Envisat Sensor Geophysical Data Records and the adoption of different values for the width of the PTR. Results show that near coast ALES estimations of SWH are generally better correlated with buoy data than standard processed products.