激光海表面散射特性及海洋次表层光学参数的激光遥感研究

The atmosphere, ground, sea surface and underwater backscattering signal could be obtained simultaneously by airborne and spaceborne lidar, so it is significant to do the research on the laser sea surface and subsurface backscattering for the understanding of the sea surface backscattering properties and the ocean detection application. The characteristics of sea surface backscattering including the amplitude and Doppler properties was simulated and analyzed, and the experimental data from airborne wind lidar was used for the validation of wind-derived sea surface backscattering properties. The sea surface movement will be simulated and Doppler shift from sea surface will also be analyzed, and the calibration method of zero-wind will be studied. Secondly, the High Spectrum Resolution Lidar for atmospheric wind detection are extended to the field of ocean optical detection. The backscattering signal from water molecules and suspended particles will be separated by the iodine filter used for atmosphere Doppler discrimination. In this way, the ocean optical parameters of water backscattering coefficient and extinction coefficient could be retrieved. The studies on the laser sea surface backscattering calibration algorithm and subsurface detection with new method are significant and needed for the future spaceborne lidar.

机载、星载大气激光雷达可以同时获取大气、地面、海面以及水下散射信号，因此进行激光海表面及次表层的相关研究，对于了解激光在海表面的散射特性及其在海洋激光雷达探测中的应用具有重要的意义。本项目首先针对激光的海表面散射的强度特性和多普勒特性开展仿真分析研究，并利用激光雷达机载实验数据开展数据分析，验证受海表面风驱动的激光海表面反射率特征，完善海表面反射率模型，仿真分析偏离天底角测量方向的海表面运动带来的径向速度影响，提出多普勒激光雷达海表面零风速校准方法；其次结合高光谱分辨率多普勒激光雷达大气探测的应用基础，将其拓展到海洋探测应用的新领域，利用碘分子吸收滤波器的高光谱分辨率特性分离测量水分子散射和海中悬浮物散射，反演海洋次表层的海洋光学参数参数。该项目的研究能够为计划上星的激光雷达系统提供完善的海表面散射校准算法及海洋次表层激光探测新方法。

为了更好的研究空间多普勒激光雷达海表面散射信号的特点和应用，本文基于机载激光雷达获取的海表面散射信号进行了强度信息和多普勒信息特征的研究以及水下散射信号测量的方法研究。从实际的激光雷达数据出手，给出了空间激光雷达实现准确地/海表面信号位置提取、类型鉴别、强度大小提取的方法和算法。通过模拟和实验分析了海表面散射信号的强度特征，综合考虑海表面的反射率模型，实验数据的处理结果和模型曲线吻合较好，反映了海表面风速影响，验证了受海表面风驱动的海表面反射特征模型，并通过实验数据分析强调了UV、蓝绿光波段的海表面反射考虑海水体散射贡献的必要性，以及估算了水下散射等效海表面反射率大小。.从海表面波形的仿真入手分析了激光海表面散射信号的多普勒特征，实验分析了地/海表面散射信号应用于机载多普勒激光雷达零风速校正的可行性，并提出了基于地/海表面散射信号的零风速校准的方案。.利用碘分子吸收滤器实现了不同线型的水分子散射信号和悬浮物散射信号的分离测量，给出了海洋次表层海洋光学参数的反演算法，通过ADL飞行实验从原理和实验上初步证实了该方法的可应用性。.本文的研究内容对将来的机载、星载多普勒激光雷达的应用和开发具有一定的参考价值，尤其是对欧空局即将发射的ALADIN星载多普勒激光雷达的后续数据算法具有应用价值。