不同浓度悬浮泥沙水体的光谱吸收特性模拟

Simulation of Spectral Absorption Characteristics of Suspended Sediment Water

悬浮泥沙的光学特性是影响内陆湖泊水色遥感的重要因素。利用光谱吸收衰减仪（AC-S）测得水池中悬浮泥沙浓度为2．13～1442．40mg／L的水体光谱吸收。在蓝、绿和红光波段，悬浮泥沙水体的平均比吸收系数分别为0．0161±0．0039m^2·g^-1、0．0071±0．0020m^2·g^-1和0．0025±0．0007m^2·g^-1；指数拟合获得的Sm^＊值为0．0098±0．0011nm^-1，利用其模拟的比吸收光谱与实测光谱吻合效果较好，说明该孓取值对悬浮泥沙水体比吸收光谱的曲线斜率变化具有一定的参考价值。此外，建立了悬浮泥沙水体吸收系数a（440）m与其浓度的关系模型，R^2达0．947，拟合精度较高；然而比吸收系数a^＊（440）m与泥沙浓度几乎无相关性。研究结果可为内陆水色遥感分析模型的建立提供重要的参数保障。

Optical properties of suspended sediments affect strongly water color remote sensing in inland lake. This study maae use of AC-S （Wetiabs Inc） to measure absorption coefficients of suspended sediment water in a pool, whose concentrations changed from 2.13 mg/L to 1 442. 40 mg/L. Average specific absorption coefficients of suspended sediment water are respectively 0. 01614-0. 0039 m^2·g^-1,0.0071±0. 0020 m^2·g^-1 and 0.00254-0. 0007 m2·g^-1 at blue,green and red wave bands. Curve factor of specific absorption spectra Sm^＊ can be obtained hy exponential fit, which is 0. 0098：1： 0. 0011 nm^-1. And the modeled spectra can suit to the measured spectra best,which indicates that the Sm^＊, value can present slope variation of specific absorption spectra very well In addition, the relationship model between absorption coefficient a（440）m and suspended sediment concentration has been established, where R2 reaches 0.947. Conversely, the correlation of specific absorption coefficient a（440）m and suspended sediment concentration is very low. All these can support important parameters for analysis model of water color remote sensing in inland lake.