基于生物光学模型的二类水体光学活性物质估算：以晋江下游河段为例

水体中各组分对光谱的吸收和散射构成了水体的固有光学特性，是生物光学模型的重要参数，是建立水质遥感半分析模型的基础.目前该方法多应用于湖泊水质监测，很少用于河流.因此, 本研究以福建晋江下游河段为例, 探讨水面下反射率R(0^-)与光学活性物质之间的关系，并建立了光学活性物质的估算模型.结果表明，利用R(0^-)₇₅₃与总悬浮物浓度、R(0^-)₇₀₂/R(0^-)₆₈₀与浮游植物色素浓度、R(0^-)₆₇₀/R(0^-)₄₂₃与CDOM吸收系数分别建立的估算模型能取得理想的效果，其决定系数分别是0.953、 0.820 5和0.621 3，对应的相对误差分别是6.1%、 21.87%和22.18%.三者中以悬浮物浓度的反演精度最高，然后依次为浮游植物色素浓度和CDOM.主要原因在于浮游植物色素的浓度相对较低，光谱信号较弱；CDOM的特征光谱波段很窄，而且该波段内的R(0^-)受到其它２种物质存在的影响.

Estimation of the Optically Active Substances in Case Ⅱ Water of the Lower Jinjiang River Based on the Bio-optical Model

The water's Inherent Optical Properties (IOPs), including absorption and scattering coefficients of water components, are the essential parameters for bio-optical model and retrieval of water quality using the semi-analytical method. Nevertheless, the application of the bio-optical model in river water studies is still very rare. Therefore, taking the lower Jinjiang River of Fujian, SE China as an example, this study measured and calculated the bio-optical properties of river water and concentrations of optically active substances based on in situ water samples collected from river in 2007. It shows that R(0^-)₇₅₃, R(0^-)₇₀₂/R(0^-)₆₈₀ and R(0^-)₆₇₀/R(0^-)₄₂₃ can be used to estimate total suspended solids (TSS) concentration, phytoplankton pigment (PP) concentration and the CDOM absorption at 440nm, respectively. The determination coefficients (R²) of the retrieval model of TSS, PP and CDOM are 0.953, 0.820 5 and 0.621 3, respectively. The corresponding relative errors of the models (RE) are 6.1%, 21.87% and 22.18%. The results show that the model for estimating TSS can achieve the highest accuracy, the PP-estimating model has the second highest accuracy and the CDOM-estimating model has the lowest. The relatively lower concentration of phytoplankton pigments, narrow characterized spectral range of CDOM and influence of CDOM's R(0^-) by TSS and PP within this spectral range contributed to their relatively lower accuracy.