Structured Sun glitter recorded in an ASTER along‐track stereo image of Nam Co Lake (Tibet): An interpretation based on supercritical flow over a lake floor depression
Structured Sun glitter recorded in an ASTER along‐track stereo image of Nam Co Lake (Tibet): An interpretation based on supercritical flow over a lake floor depression
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DOI：
10.1029/2007jc004204
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发表时间：
2008
影响因子：
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通讯作者：
J. Matthews;Xuejuan Yang;Junqiang Shen;T. Awaji
中科院分区：
文献类型：
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作者：
J. Matthews;Xuejuan Yang;Junqiang Shen;T. Awaji
[1]太阳闪烁和合成孔径雷达（SAR）遥感技术，对小规模的粗糙表面的水，往往揭示了大量的签名，表明存在的床形成淹没在浅水中（深度为0.4 m s-1），随后形成表面电流梯度（“应变”）的数量级为10 - 3 s-1，并随之而来的厘米级表面粗糙度的局部调制控制光和雷达的散射。在这里，我们考虑如何分层的存在可能会影响这一生成序列的高灵敏度太阳闪烁观测时，背景流速和表面电流梯度至少低一个数量级的分析。高级星载热发射和反射辐射计（ASTER）于2001年7月22日获得了这些观测结果，同时从倾斜视场以沿轨道立体模式成像，该视场包括从纳木错表面反射的太阳闪光，纳木错是西藏的一个大湖，没有人为的表面浮油污染。我们解释一个结构化的太阳闪烁功能出现在一个浅海湾西北部的湖泊作为表面粗糙度的表现形式的超临界分层流形成的唤醒在湖底地形的局部凹陷。
[1] Sun glitter and synthetic aperture radar (SAR) remote sensing techniques that respond to the small-scale textural roughness of water surfaces often reveal a plethora of signatures indicative of the presence of bed formations submerged in shallow water (of depth 0.4 m s−1), the subsequent formation of surface current gradients (the “straining”) of order 10−3 s−1, and an ensuing local modulation of the centimeter-scale surface roughness controlling the scattering of both light and radar. Here we consider how the presence of stratification might influence this generative sequence in an analysis of high-sensitivity Sun glitter observations gathered when the background flow speed and surface current gradients are at least one order of magnitude lower. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) acquired these observations on 22 July 2001 while imaging in along-track stereo mode from slanted fields of view that encompassed Sun glitter reflected from the surface of Nam Co, a large Tibetan lake that is free from anthropogenic surface-slick contamination. We interpret a structured Sun glitter feature appearing within a shallow embayment in the northwest of the lake as the surface roughness manifestation of a wake formed by supercritical stratified flow over a localized depression in the lake floor topography.