鄱阳湖富营养化高光谱遥感监测模型初探

基于对光谱反射率与水质参数的相关分析,分别选取特征波长建立水质参数高光谱估测模型。结合修正营养状态指数,对湖泊的富营养化程度进行了监测和评价。结果表明:①总氮、总磷含量和透明度值的高光谱估测模型效果较理想;②单项指数评价水体富营养化水平其结果存在较大差异,综合考虑多个指标,计算营养指数的平均值,可以对富营养化程度进行正确的评价;③由于悬浮物浓度变化较大,掩盖了水体的叶绿素a信息,以致叶绿素a估测模型不具有通用性,为了完善叶绿素a浓度估测模型需要获得大范围、多季节的光谱数据,以便建立更有代表性和通用性的模型;④评价结果显示,鄱阳湖呈现轻度到中度富营养化状态,需要采取有力的保护措施防止进一步恶化。

Hyperspectral monitoring model of eutrophication in Poyang Lake

This study presents an approach for monitoring and evaluating the eutrophic state with field reflectance spectra in Poyang Lake. Based on the correlation of water parameters and spectral reflectance, the estimating models of water parameters have been developed. With the TLI eutrophic state index model, the lake eutrophic states are monitored and evaluated. The result shows: 1) The effect of algorithms of SD, TN and TP is good; 2) Single parameter TLI compared with multi-parameter TLI is limited. Using average of multi-parameter TLI, the evaluation of eutrophication is more accurate; 3) The great change of suspended sediments concentration covered up the information of Chlorophyll-a, so the estimating model of Chlorophyll-a is not universal. It needs more spectral data in big range and the four seasons to build and improve more representational models; 4) Poyang Lake is in eutrophic state, and needs to be prevented from furtherworsen.