海洋环流与波动重点实验室知识库

海浪和海流是海洋动力参数的重要组成部分，准确获取高精度的海浪和海流信息，对于科研、海上工程、监测污染物的流动并优化海洋能源利用、国防等都具有重要意义。海洋遥感以其长时间尺度、大面积观测的特点成为获取海洋动力要素的重要技术手段。

传统高度计观测模式的发展日趋成熟，但是由于仪器噪音水平与观测方式的限制，难以分辨海面较小尺度上的变化和实行二维宽刈辐同步观测。面向海洋观测的干涉SAR测量技术，克服传统高度计的局限，能够把被观测物理量的微小变化转化为易于测量的相位变化，干涉SAR测量比传统测量在测量小量变化方面有巨大优势，成为新一代海洋遥感发展的一个方向。干涉SAR测量包括交轨干涉（观测海面高度）和顺轨干涉（观测海流）。美国SWOT交轨干涉SAR测高卫星计划于2022年11月份发射，旨在把卫星观测的海面高度变化分辨率提高一个数量级，顺轨干涉SAR测流已经在欧美未来海洋观测计划中立项，是遥感测流最有希望的方式之一。我国也在开展相关预研工作或在轨卫星实验，相关数据稀少而宝贵。本文基于国产交轨干涉SAR机载载荷和高分三号卫星顺轨干涉SAR实验模式数据，开展海浪和海流反演方法研究。

海浪反演方面的主要工作和创新点：本文证明了国产交轨干涉SAR机载载荷-Ka波段交轨干涉成像高度计（Airborne Ka-band Interferometric Altimeter，AirkaIA）能够较为精确地直接观测二维海面高度变化，高分辨二维海面高度变化的同步观测为海浪研究提供了丰富的信息，本文基于该交轨干涉SAR机载实验载荷新型数据开发了首个基于二维高度变化的海浪参数反演方法，反演得到的主导波向、主导波长和有效波高（SWH）均与实测数据有很好的一致性。相关工作丰富了海浪参数遥感反演方法，验证了国产交轨干涉SAR载荷AirkaIA的性能，对我国下一代国产干涉SAR星载平台的研发具有重要的借鉴意义。

海流反演方面的主要工作和创新点：本文基于高分三号卫星顺轨干涉SAR实验模式数据，探究了提高海流反演精度和获取二维矢量海流的方法，包括：（1）利用二维经验模态分解（BEMD）降低大尺度波轨道速度造成的误差；（2）通过求解多点观测径向海流的最小代价函数获取二维矢量海流；获得的二维海流流速与模式预报数据之间的回归系数在0.6-0.8左右，相关系数R-square在0.9左右，均方根误差RMSE在0.01m/s左右，获得的二维海流流向与模式预报数据之间的平均偏差在30度左右；相关工作丰富了顺轨干涉海流遥感反演方法，展示了高分三号卫星顺轨干涉SAR实验模式的海流测量潜力，为进一步拓展高分三号卫星数据应用场景提供了有益借鉴。

Sea surface waves and currents are an important part of marine dynamic parameters. Accurately obtaining high-precision information on waves and currents is of great significance for scientific research, offshore engineering, monitoring the flow of pollutants, optimizing the utilization of marine energy, and national defense. Ocean remote sensing has become an important technical means to obtain marine dynamic parameters due to its characteristics of long-term scale and large-area observation.

The development of traditional altimeter becoming more mature, it faces great challenges in distinguishing small-scale changes in the sea surface due to the limitations of instrument noise levels and observation methods. The interferometric SAR measurement technology for ocean observation can convert small changes in the observed physical quantities into phase changes that are easy to measure. Compared with traditional measurement, interferometric SAR has huge advantages in measuring small changes, and it has become a direction for the development of a new generation of marine remote sensing. Interferometric SAR measurements include cross-track mode (observing sea surface height) and along-track mode (observing ocean currents). The cross-track interferometric-US SWOT satellite is planned to be launched in November 2022, aiming to increase the resolution of the sea surface height by an order of magnitude. The current measurement by along-track interferometric SAR has been approved in the future ocean observation plan of developed countries, and it is one of the most promising methods of remote sensing current measurement. China is also carrying out relevant pre-research work or in-orbit satellite experiments, and relevant data are scarce and valuable. In this paper, based on the civil interferometric SAR airborne payload and the Gaofen-3 satellite ATI data, the study on retrieval algorithms of sea surface waves and currents is carried out.

Main work and innovations in sea surface waves remote sensing. This paper describes the new ability to measure sea surface waves using the airborne Ka-band interferometric altimeter (AirKaIA). Although the original definition of wave parameters is derived from wave-induced sea surface elevation (WSSE), it is difficult to directly measure the WSSE, so most remote sensing of waves use other types of signals to obtain wave parameters. Here we present the measurement of two-dimensional (2D) WSSE from AirKaIA. A new wave retrieval method based on the 2D WSSE has been developed, tested with simulation data and applied to AirKaIA data. The results indicate that the retrieved dominant wave directions, dominant wavelengths and significant wave heights from AirKaIA are in agreement with in-situ measurements while highlighting the need for further method tests using more observations. The study of ocean signals from interferometric altimeter is an emerging research topic. AirKaIA’s measurements of sea surface waves with 2D WSSE have implications for the assessment of future interferometric altimeter missions.

Main work and innovations in sea surface currents remote sensing.This paper describes the method to improve sea surface currents remote sensing accuracy and obtain the two-dimensional vector of sea surface currents based on the ATI experimental model data of the civil Gaofen-3 satellite. Relevant work includes: 1) using bidimensional empirical mode decomposition (BEMD) to reduce the large-scale wave orbital velocity, 2) the two-dimensional vector of sea surface currents is obtained by solving the minimum cost function of the multi-point radial currents, and the regression coefficient between the retrieved current velocity and the ROMS forecast data is about 0.6-0.8, and the correlation coefficient R-square is about 0.9, the root mean square error (RMSE) is about 0.01m/s, and the average bias between the retrieved current direction and the ROMS forecast data is about 30 degrees. The related work has enriched the sea surface currents remote sensing retrieval method, demonstrated the ocean current measurement potential of the ATI experimental model data of the civil Gaofen-3 satellite, and provided a useful reference for further expanding the application scenarios of the GF-3 satellite data.

第1章 引言

1.1 干涉SAR海浪和海流反演的研究意义

1.2干涉SAR海浪和海流反演的国内外研究进展

1.3 研究思路和内容

第2章 干涉SAR海浪和海流反演理论基础

2.1 海洋表面波的类型

2.2 海洋表面流的成分

2.3 干涉SAR工作机制

2.4 干涉 SAR测量原理

2.5本章小结

第3章 交轨干涉SAR海浪反演

3.1 数据源

3.2 反演方法

3.3 反演结果和验证

3.4 本章小结

第4章 顺轨干涉SAR海流反演

4.1 数据源

4.2 反演方法

4.3 反演结果和验证

4.4 本章小结

第5章 总结与讨论

5.1 本文内容总结

5.2 将来工作展望

参考文献

致  谢

作者简历及攻读学位期间发表的学术论文与研究成果