长春市南湖叶绿素a浓度高光谱估测模型研究

Hyperspectral model of chlorophyll-a concentration in Nanhu lake in Changchun

利用野外高光谱仪(ASD FieldSpec radiometer)在长春南湖进行了反射光谱测量和同步水质采样分析,通过研究水体藻类叶绿素a浓度与其高光谱反射特征之间的相关关系,采用单波段反射率、反射率比值法和一阶微分法分别建立了叶绿素a的高光谱定量模型。结果表明:三者与叶绿素a线性相关程度都比较高,决定系数在0.70左右,而且其显著水平P<0.01,都可以用于叶绿素a的定量遥感,其中单波段模型效果最好。为今后利用高光谱传感器在南湖进行叶绿素a浓度大面积遥感反演提供了研究基础。

This study presents an approach to the determination of the trophic parameters of ehlomphyⅡ-a from field reflectance spectra in Nanhu lake in eutrophic status in Changchun. The reflectance spectra was measured using ASD FieldSpee spectrometer from April to september in 2004. Based on in situ water samplies and the reflectance measurements, the features of the spectral reflectance of the water are discussed. Algorithms are developed to evaluation the spectral data. The single band R753nm, the spectra ratio of R753nm/R681nm, and the reflectance first-derivative of 700 nm, showing a linear relationship, are found to be significantly correlated with the concentration of chlorophyⅡ-a, and the determinative coefficient R2 gained by using the single band is higher than that gained with other two models.There is satisfactory correspondence between hyperspectral models and chlorophyⅡ-a concentration, therefore, it is possible to monitor the water quality of Nanhu lake throngh the hyperspetral remote sensing data.