内陆湖泊悬浮泥沙垂直分布遥感监测机理研究

The covariance relationships between the suspended sediment concentration, particle size, and optical characteristics and radiation transmission properties are researched in different water depths through field tests and laboratory experiments in Hongzehu Lake and Dongting Lake; the response mechanism of water scattering and backscattering optical properties on the suspended sand size distribution spectrum is explored combining with the particle size structure model and the Mie scattering model; the vertical stratified water radiative transfer model is constructed by integrating the vertical distribution of suspended sediment concentration model and the radiative transfer model to reveal the influence mechanism of surface reflectance by the vertical structure of suspended sediment concentration and particle size; the optimization algorithm based on constraint factor is researched, and therefore, the remote sensing inversion model of vertical distribution of suspended sediment is constructed through the multidimensional look-up table, which is composed by the vertical distribution of suspended sediment concentration, the underwater light field parameters, and the water remote sensing reflectance. The study should break the limitations of the water surface parameters inversion. Thus, it should transfer the inversion from 2D to the three-dimensional and push the parameter retrieving toward different depth. The research results should provide data support for the study of lake morphology and environmental changes. Moreover, this should provide technical support for revealing the response of sediment transportation on water conservancy engineering in large rivers and lakes, and for tracing the effects of the sand extraction on the water environment.

以大型通江湖泊如洪泽湖、洞庭湖为典型研究区域，通过野外原位实验和实验室实验，观测分析悬浮泥沙浓度、粒径结构等垂直分布与水体不同深度光学特征以及辐射传输特性的共变关系；结合颗粒物粒径结构模型和米散射模型，探索水体散射、后向散射光学特性对悬浮泥沙粒径谱分布的响应机理；融合悬浮泥沙浓度垂直分布模型、辐射传输模型，构建光学垂向分层水体辐射传输模型，揭示不同悬浮泥沙浓度和粒径垂向结构对表面遥感反射率的影响机制；通过悬浮泥沙垂向分布—水下光场参数—水面遥感反射率多维拟合查找表，研究基于条件约束的查找表优化算法，构建悬浮泥沙垂直分布遥感反演模型，突破以往研究停留于水体表层参数反演的局限，实现遥感“二维”反演到“三维”反演的拓展，推进遥感技术向水体不同深度参数反演的方向发展。项目研究成果可为湖泊形态、环境变迁等研究提供数据支持，为揭示大型通江湖泊泥沙疏运与水利工程的响应关系、追踪采砂等人为活动对水环境的影响提供技术支持。

本项目以洪泽湖为研究区，研究以悬浮泥沙为光学主导的内陆浑浊水体的光学传输机理，构建悬浮泥沙浓度垂向分布遥感反演模型。根据多次洪泽湖野外实验的实测水质、光学数据，分析水下光场信息与水色要素及悬浮泥沙粒径的响应关系，确定水体辐射传输模拟的边界值，率定水柱中吸收系数、散射系数等关键光学参数，基于水体辐射传输模型，实现了从不同水层物质组成(组分、浓度、粒径)—固有光学特性—表观光学参数的正演过程，构建了适用于洪泽湖的无机悬浮物颗粒浓度表层—垂向参数查找表。建立了适用于哨兵3/OLCI(Ocean and Land Color Instrument)数据的查找表匹配方法，实现了从遥感反射率到不同深度无机悬浮物浓度、总悬浮物浓度的遥感反演。.发表论文22篇，其中，SCI收录论文20篇，完成了预期指标。