珠江口水体叶绿素荧光特性研究

Research on chlorophyll fluorescence properties of water in Zhujiang River estuary

利用2003年1月和2004年1月珠江口实测的遥感反射率和叶绿素浓度,建立了基于实测1nm带宽及其模拟MERIS遥感反射率数据的叶绿素荧光特征与叶绿素浓度之间的拟合关系。基于实测1nm带宽遥感反射率光谱,叶绿素荧光峰的位置和高度分别与叶绿素浓度之间存在良好的线性关系和指数关系;基于模拟MERIS遥感反射率数据,叶绿素荧光峰的高度与叶绿素浓度之间存在良好的线性关系,叶绿素荧光峰位置与叶绿素浓度之间不存在明显的相关关系,但可作为叶绿素浓度数量级的有效探针。利用2006年5月和8月的珠江口实测遥感反射率和叶绿素浓度对拟合结果进行了检验,结果表明其精度较高,说明叶绿素荧光特征在探测叶绿素浓度时效果良好且MERIS数据在近岸二类水体叶绿素浓度反演、水质监测等方面有着良好的应用前景。

Based on the in-situ remote sensing reflectance collected in the Zhujiang River estuary in Jan. 2003 and Jan. 2004, the red and infrared remote sensing reflectance spectra with lnm bandwidth and MERIS wavebands 6 to 12 were calculated. Combining with the synchronous in-situ chlorophyll concentrations, the correlation relationships between chlorophyll fluorescence properties and chlorophyll concentrations were concretely analyzed and then tested by the in-situ remote sensing reflectance and chlorophyll concentrations collected in the Zhujiang River estuary in May and Aug. 2006. Good linear relationships be- tween the fluorescence line heights and chlorophyll concentrations were found both based on the in-situ reflectance spectra with 1 nm bandwidth and based on the simulated MERIS remote sensing reflectance spectra, with re of 0. 896 and 0. 898, and average relative errors of 0. 089 and 0. 086, respectively. A good exponential relationship between fluorescence peak positions and chlorophyll concentrations was found based on the in-situ reflectance spectra with lnm bandwidth, with re of 0. 902 and average relative error of 0. 042, respectively. No outstanding correlation relationship between chlorophyll concentrations and fluorescence peak positions was found based on the simulated MERIS reflectance spectra, but the MERIS peak position could be taken as an effective magnitude index of chlorophyll concentration. It is indicated that chlorophyll fluorescence properties are effective in detecting chlorophyll concentration, and MERIS data is good at retrieving chlorophyll concentration and monitoring water quality in coastal and inland environments.