太湖水面多角度遥感反射率光谱测量与方向特性分析

水体光场不是各向同性的，其方向性分布规律的研究对于水质参数遥感反演建模具有十分重要的意义。大洋水体光场的二向性研究已经相对比较成熟，而内陆水体光场的二向性分布规律研究仍存在许多问题。水面原位多角度光谱测量数据是分析水体光场二向性的重要依据，但是目前国际上还缺少相关测量设备。设计并制作了一种能够在野外原位测量水面光场二向性的多角度水面光谱测量杆，它可以配合光谱仪测量多个角度的水面遥感反射率光谱。利用该设备在太湖开展了一次水面多角度光谱测量实验，利用该实验获取的数据分析了太湖水面遥感反射率光谱的方向性分布规律, 进而给出了能够降低方向性影响的水质参数遥感反演建模策略。

Analysis of Directional Reflectance Properties of Lake Taihu Using Multi-Angle Measurements

The optical field above water is not isotropic. It is important to study the directional reflectance properties of the optical field above water, which is useful for building water quality parameters retrieving models by remote sensing. The bidirectional reflectance distribution function above oceanic waters has been well studied. However, the bidirectional reflectance distribution function above inland waters is still unresolved. The in-situ measured multi-angle remote sensing reflectance above water provides valuable data for studying directional reflectance properties above water. Unfortunately, such data is almost unavailable for inland waters due to the lack of of feasible instrument. Therefore, the authors designed and manufactured a specialized device to measure in situ multi-angle remote sensing reflectance involving with a spectrometer. We carried out an experiment in Lake Taihu to measure in situ multi-angle remote sensing reflectance data with this device. Then, we analyzed the directional properties of the remote sensing reflectance above water surface of Lake Taihu, and their effects on building water quality parameters retrieving models by remote sensing. Finally, we proposed a strategy for building water quality parameters retrieving models, which could reduce the directional effects of the optical field above inland waters.