长春市南湖富营养化高光谱遥感监测模型

Hyperspectral Monitoring Model of Eutrophication in Lake Nanhu,Changchun

通过对长春市南湖水质参数和高光谱反射率的相关分析,建立两者间的一元回归模型;同时利用日本学者相崎守弘等人提出的修正营养状态指数(TSIM)模型,分别针对水质参数实验室数据和高光谱数据,对长春市南湖富营养化程度进行评价和监测.结果表明:1)利用高光谱遥感监测模型进行湖泊富营养化监测和评价,能够获取较为准确的评价结果,相对于传统监测方法具有省时省力的特点;2)用实验室数据得出的TSIM修正营养状态指数,各点数据起伏比较大,而高光谱遥感监测模型模拟营养状态指数相对平缓,这表明监测模型对各点数据进行了不同程度的同化,相对缩小了同期各点数据和异期同点数据之间的差异,这与实验室化学分析数据监测结果相比是一个不足之处;3)长春市南湖水体呈现较为严重的富营养化状态,需要采取措施防止南湖水质进一步恶化.

This study presents an approach for the determination of the trophic state from field reflectance spectra in Lake Nanhu of Changchun,which was in eutrophic status. Reflectance spectra were measured from April to July in 2004, with ASD FieldSpee spectrometer. Based on in situ water sampling and reflectance measurements, algorithms of Chlorophyll-a, TN and TP have been developed. With the TSIM trophic state index model, the lake trophic state are monitored and evaluated. The model equations as follows ： TSIM（Chla） = 10[2.46 ＋ ln（Chla）/ln（2.5）] TSIM（TN） = 10[2.46 ＋ （0.3155 ln（TN） ＋ 4.5998）/ln（2.5）] TSIM（TP） = 10[2.46 ＋ （0.3939 ln（TP） ＋ 5.4415）/ln（2.5）] TSIM（AVE） = [TSIM（ Chla） ＋ TSIM（TN） ＋ TSIM（ TP） ]/3 The result shows： 1 ） TSIM model to evaluate lake water trophic state, may obtain accurate result normally, with little time, effort and money; 2 ） The TSIM trophic states of hyperspectral simulation data, compared with that of laboratory data, narrow the differences of the same point in different months and different points in one same month; 3 ） Lake Nanhu is in serious eutrophic state, and needs to take measures to prevent the water quality from worsening further.