卫星合成孔径雷达探测海底地形研究进展

摘要

Using satellite synthetic aperture radar (SAR)to detect ocean bottom topography is a challeng-ing problem for the research of ocean remote sensing physics and ocean dynamics.The reason is that radar pulses are unable to penetrate into seawater based on the principles of electromagnetic wave propagation, thus unable to detect ocean bottom topographic features directly.However,ocean bottom topographic fea-tures indeed show up on satellite SAR images in many cases.These topographic features are distributed not only in the shallow waters with depths shallower than 100 m,but also in the deep waters with depths deeper than 600~800 m and even 2000~3000 m.This paper overviews the frontier and progress in studies of this field.The key points include the fundamental theories for radar imaging of ocean surface processes, the SAR imaging theories for ocean bottom topographic features in three ocean areas:the Liaodong Shoal and the Taiwan Tan of China as well as the Gulf Stream region east of USA.The three cases represent lon-gitudinal shear flow passing over parallel ocean bottom topography,stratified traverse flow crossing over parallel (periodic)ocean bottom topography and strong ocean current passing over isolated ocean bottom topography.The theories and analysis methods derived from the three cases may serve as a baseline for in-terpretations of more complex cases and explorations of new application fields.%利用卫星合成孔径雷达(SAR)图像信息探测海底地形是海洋遥感物理学和海洋动力学研究具有挑战性的问题，这是因为根据电磁波传播原理，雷达脉冲没有能力穿透海水，因而不可能直接探测到海底地形特征，可是，许多卫星 SAR 图像上确实显示出海底地形特征。这些海底地形不仅分布在水深小于100 m 的浅海，而且在600~800 m 甚至2000~3000 m 的深海区也有发现。本文概略介绍该领域的发展前沿和研究进展，主要内容包括海面过程雷达成像基本理论，我国辽东浅滩、台湾滩以及美国东部湾流海域等3个海区海底地形特征 SAR 成像理论：分别为速度切变流纵向流经平行海底地形、层化流体横向流流经平行(周期性)海底地形和强海流流经孤立海底地形。据此建立的理论和分析方法可做为研究更复杂情况和探索新应用领域的基础和出发点。