Abstract:
Dianchi Lake is one of the seriously polluted plateau lakes and water quality monitoring in Dianchi Lake has attracted much attention. Monitoring water quality by hyperspectral remote sensing is convenient for long-term dynamic monitoring and the spatial distribution difference and migration characteristics of pollution sources. In this paper, ZH-1 hyperspectral satellite data were used to select, from the spatial scale, water bodies in different regions of Dianchi Lake for hyperspectral test analysis and comparison. The test results show: ① The difference of reflectivity between Caohai and offshore water bodies in the study area is the largest in the near-infrared band, which can be used for the identification and extraction of two kinds of water bodies, as well as the preliminary determination of chlorophyll content in water bodies. ② The spectral curves of the water bodies at the inlet and outlet in the study area varied abnormally within the range of 880—940 nm, which could be used for the identification and extraction of the two water bodies, and it was speculated that the change trend was caused by the influence of suspended particles in the water. ③ In the near infrared band, the reflectivity difference between the water bodies in the lake center and the shore zone first increases to the maximum and then decreases gradually. According to this spectral feature, the identification and extraction of water bodies in the two regions can be realized, and it is speculated that the spectral difference is caused by the influence of suspended matter concentration in the water. In conclusion, near-infrared band has good spectral response characteristics, which can better reflect and identify the spatial distributive difference within lakes, and can also make a good judgment on the difference of water environment conditions.