基于地面实测光谱的太湖水体富营养化水平估算

Trophic state level monitoring of Lake Taihu based on in situ measurements of hyperspectral reflectance

富营养化指数是评价水体污染情况的一个重要的综合性指标．通过对高光谱遥感数据和水体富营养化指数的分析,确立了反演水体富营养化水平的高光谱敏感波段,进而用选择的敏感波段和波段组合来建立模型．通过对几个模型的比较,选出了较为理想的估算模型．最后对模型进行精度分析,认为该模型具有一定的可靠性和实用性．从而确定了直接由高光谱遥感数据监测水体富营养化水平的可能性,为实现由高光谱遥感数据开展大范围的水质调查奠定了一定的理论基础．

Trophic state index is an important and synthetic standard for estimating the pollution status of water body. It requires large scale field sampling work and complicated indoor chemical analysis involving traditional analytical techniques, as well as complex calculations applying complicated formulas. In this study, through the analysis of the hyperspectral remote sensing data and the water body trophic state level, the remote sensing reflectance and trophic state index of the water body, Lake Taihu, are calculated, The result of correlative analysis, found the hyperspectral sensitive bands to be inverse to the water-body＇s trophic state index and sensitive bands and bands＇ combination （ratio） in established models. The comparative baseline model selected is a power function model TSIc = 68.76 x^0.5199 , with an independent variable of R717nm. The result, through precision analyses using the other 12 points, found the differences between practice and forecast along half one grading interval, therefore providing reliability and practicability. In conclusion, it is possible to monitor a water-body＇ strophic state index directly with hyperspectral remote sensing data and some evidence for the theoretical basis of investigating water quality in a large scope using hyperspectral remote sensing data is justified.