海洋激光雷达水体光学特性参数反演模型对比及分析

Comparison and Analysis of Inversion Models for Water Optical Property Parameters by Ocean Lidar

激光雷达回波中的多次散射量决定了衰减系数KLidar,从而对水体光学特性参数的反演产生影响。目前的海洋激光雷达理论中,均以Walker-McLean模型和多次前向-单次后向散射模型的公式形式表示多次散射分量。根据水下激光传输机制,分析了这两种模型中多次散射因子的等效性,并将其多次散射项进行对比,讨论了利用这两个模型反演水体光学特性参数的异同。对比两种模型的散射相函数发现,Walker-McLean模型更符合实测情况;多次前向-单次后向散射模型适应于前向散射极强的介质。在激光刚进入水体时,其水体光学特征参数反演值会偏低,并随着多次散射次数的增加而变得偏高。

The proportion of multiple scattering in the lidar echo determines the attenuation coefficient KLidar,which affects the inversion of the water optical property parameters.At present,the Walker-McLean model and the multiple forward scattering-single backscattering model are both expressed with the formula form to describe multiple scattering components in the theory of ocean lidar.Based on the underwater laser transmission mechanism,the equivalence of multiple scattering factors in these two models is analyzed,and the items involving multiple scattering are compared to discuss the similarities and differences of these inversion models for water optical property parameters.Based on the comparison of scattering phase functions of the two models,it is found that the results obtained based on the WalkerMcLean model are more consistent with measured results.Multiple forward scattering-single backscattering model is suitable for medium with strong forward scattering.The inversion value of water optical properties is lower than the actual value when the laser just enters into water,and it gets higher value as the multiple scattering times increase.