高叶绿素水体荧光峰位置变化响应关系研究

Fluorescence Peak Shift Corresponding to High Chlorophyll Concentrations in Inland Water

水体反射光谱红光区荧光峰是叶绿素特有的光谱特征,研究其位置变化与叶绿素的响应关系有助于内陆水体叶绿素含量的定量反演。通过2004-2006年13次长春南湖水体反射光谱和水质参数实测数据,分析了不同光谱分辨率下荧光峰位置变化与叶绿素a含量的响应关系,结果表明,两者呈现指数函数关系,即Peak position=a（Chl-a）b,不同光谱分辨率下,a在686.11-686.29,b在0.0062-0.0065间变化,且光谱分辨率越高,响应关系越好;荧光峰平均波长位置与叶绿素平均含量高度相关（R2〉0.81）,荧光峰位置变化适合用于反演叶绿素含量分布较为均匀的水体。这为今后利用成像光谱仪监测内陆水体叶绿素含量提供了实验和工作基础。

Hyperspectral remote sensing offers the potential to detect water quality variables such as Chl-a by using narrow spectral channels of less than 10 nm,which could otherwise be masked by broadband satellites such as Landsat TM.Fluorescence peak of the red region is very important for the remote sensing of inland and coastal waters,which is unique to phytoplankton Chl-a that takes place in this region.Based on in situ water sampling and field spectral measurement from 2004 to 2006 in Nanhu Lake,the features of the spectral reflectance were analyzed in detail with peak position shift.The results showed： An exponential fitting model,peak position=a（Chl-a）^b,was developed between chlorophyll-a concentration and fluorescence peak shift,where a varies between 686.11 and 686.29,while b between 0.006 2 and 0.006 5.It was found that the better the spectral resolution,the higher the precision of the model.Except that,the average of peak shift showed a high correlation with the average of different Chl-a grades,and the determination coefficient（R2） was higher than 0.81.It contributed significantly to the increase in the accuracy of the derivation of chlorophyll values from remote sensing data in Nanhu Lake.There is satisfactory correspondence between hyperspectral models and chla concentration,therefore,it is possible to monitor the water quality of Nanhu lake throngh the hyperspetral remote sensing data.