基于光谱分类的太湖水体后向散射研究

Backscattering properties and parametric model of Taihu Lake based on spectral classification

由于时空变化而产生的水体后向散射系数参数化差异一直是影响水质参数遥感定量反演精度的一个重要因素。在对太湖遥感反射率光谱进行分类的基础上,针对影响太湖水体水色的不同主导因子,把太湖水体分为3种类型,分别利用半分析方法和光学闭合原理对后向散射系数进行模拟,在此基础上研究其光学特性及其与水体组分浓度的关系,最后针对3种不同主导类型的水体分别建立了后向散射系数参数化模型。将后向散射特性在不同时间和空间上的差异转化为水体不同主导因子在生物-光学上的差异,从而得到适用于太湖不同湖区及不同季节的后向散射系数参数化模型,为利用分析方法对太湖水质参数进行更为精确的遥感反演提供了基础。

The parameters of backscattering coefficient model have significant temporal and spatial variability. In order to over- come this limit, a classification algorithm based on spectra dominant factors for Taihu Lake is established to classify the water reflectance spectra into three types. Quasi-analytical algorithm and optical closure are used in this paper to stimulate the back- scattering coefficient for three types of water reflectance spectra in Taihu Lake according to the field measurement reflectance data. The properties of backscattering coefficient are also analyzed synchronously. On this basics, the backscattering coefficient parametric model for three types of water in Taihu Lake are established. As a result, the difference of the backscattering proper- ties in different time and space is converted into the difference of bio-optical properties of dominant factor in water. Thus, the parametric models of backscattering coefficient are demonstrated to be suitable for different parts and different seasons of Taihu Lake.