Synergistic surface current mapping by spaceborne stereo imaging and coastal HF radar
Synergistic surface current mapping by spaceborne stereo imaging and coastal HF radar
复制标题
星载立体成像和沿海高频雷达协同表面电流测绘
DOI：
10.1029/2012gl052546
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发表时间：
2012
影响因子：
5.2
通讯作者：
John P. Matthews and Yutaka Yoshikawa
中科院分区：
文献类型：
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作者：
N. Moteki;and Y. Kondo;Hiroaki Miura;John P. Matthews and Yutaka Yoshikawa
经过验证的高空间分辨率（名义上小于100米）地表水流测量光学和雷达方法可以大大提高我们监测地球海洋、沿海地区、湖泊和河流的能力。随着人们对用于表面电流和波动测定的光学沿轨立体技术的兴趣日益增长，如何解释这些数据以及如何将它们与更好的验证技术所做的测量联系起来的问题出现了。在这里，我们通过与沿海高频雷达在13.9和24.5 MHz频率下观测到的同步天气流进行比较，首次系统地评估了从沿轨道立体太阳闪光（ATSSG）图像中获得的地表流，这两种雷达分别在大约1米和2米深度的表层内返回平均洋流。在我们的对马海峡（日本）试验场，我们发现这两种技术提供了基本兼容的表面电流模式，主要区别在于电流强度。在西北（南部）比较区域，2006年8月13日得到的ATSSG电流矢量的震级平均比1‐m（2‐m）深度雷达得到的相应矢量高22%（40%）。这些结果反映了近地表垂直电流结构、两种技术检测到的流动成分的差异以及仪器性能的差异。利用ATSSG、HF雷达和ADCP数据构建的垂直剖面首次解决了公海上部2米的顺风漂移问题。剖面e -折叠深度表明斯托克斯漂移来自图像中可见的10 - m波长的波。
Well validated optical and radar methods of surface current measurement at high spatial resolution (nominally <100 m) from space can greatly advance our ability to monitor earth's oceans, coastal zones, lakes and rivers. With interest growing in optical along‐track stereo techniques for surface current and wave motion determinations, questions of how to interpret such data and how to relate them to measurements made by better validated techniques arise. Here we make the first systematic appraisal of surface currents derived from along‐track stereo Sun glitter (ATSSG) imagery through comparisons with simultaneous synoptic flows observed by coastal HF radars working at frequencies of 13.9 and 24.5 MHz, which return averaged currents within surface layers of roughly 1 m and 2 m depth respectively. At our Tsushima Strait (Japan) test site, we found that these two techniques provided largely compatible surface current patterns, with the main difference apparent in current strength. Within the northwest (southern) comparison region, the magnitudes of the ATSSG current vectors derived for 13 August 2006 were on average 22% (40%) higher than the corresponding vectors for the 1‐m (2‐m) depth radar. These results reflect near‐surface vertical current structure, differences in the flow components sensed by the two techniques and disparities in instrumental performance. The vertical profile constructed here from ATSSG, HF radar and ADCP data is the first to resolve downwind drift in the upper 2 m of the open ocean. The profile e‐folding depth suggests Stokes drift from waves of 10‐m wavelength visible in the images.