石油类污染水体后向散射特性分析——以辽宁省盘锦市双台子河和绕阳河为例

Analysis of backscattering properties of petroleum polluted water: a case study at the Liaohe River and the Raoyang River in Laoning Province,China

水体悬浮物对溶解在水中的油及乳化油有吸附作用,这种作用会叠加在颗粒物上,对水体的后向散射系数产生影响,而水体后向散射系数是水色遥感的重要参数之一,对建立遥感反演石油类污染浓度半分析模型起着关键性的作用。根据2008年5月在辽宁省盘锦市辽河油田境内双台子河和绕阳河现场测定的水样,对水体组分进行浓度分析,并分别利用分光光度计及后向散射系数测量仪测定水色三要素的吸收系数和水体后向散射系数。根据获取的数据,对石油类污染水体后向散射特性进行分析,分别建立了(1)石油类污染水体后向散射系数光谱模型;(2)石油类污染水体和非石油类污染水体后向散射系数与无机悬浮物浓度的关系模型。研究结果表明:(1)在建立的后向散射系数光谱模型中,幂函数指数平均值为0.87;(2)从相关系数分析来看,对后向散射系数起主要作用的是无机悬浮物浓度,其次是石油类物质浓度,而有机悬浮物浓度几乎没有影响;(3)对于无石油类污染水体,后向散射系数与无机悬浮物浓度为对数关系模型,而与有石油类污染水体更接近线性关系模型。

Emulsificated oil and decomposed oil in water can be absorbed by suspended particles and influence the scattering properties of the particles. Backscattering coefficient is one of the important parameters on ocean color sensing and a key factor to the establishment of semi-analytical model, so as to the retrieval of petroleum pollution concentrations. The field data were collected in the rivers in Panjin City, Liaoning Province, China in May 2008, including absorption coefficients of yellow substance, de-pigmented particles and phytoplankton pigments. The backscattering data were measured by the in-situ spectral backscattering sensor, HydroScat-- 6. Water samples for chlorophyll and sediment concentrations as well as petroleum contamination were also collected. Based on the analysis of inherent optical properties, two models were established. One is the spectral model of water backscattering coefficient with petroleum pollution, and an- other is the relationship between the water backscattering coefficient and the inorganic particle concentra- tion, including two types of water, with and without petroleum pollution. The results show that （1） the averaging exponent is 0.87 for all spectral backscattering models; （2） according to the correlative coefficients between the backscattering coefficient with phytoplankton, inorganic particles, and petroleum pollu- tion, the inorganic particles have a dominant effect on the water backscattering, petroleum pollution is the next, and phytoplankton almost has not any effect, since the sediment load is higher than 100 mg/m3 ;and （3） in the waters without petroleum pollution, the relationship between sediment concentration and back- scattering coefficient is well formulated by logarithm function, however, in the waters with petroleum pol- lution, the linear relation is more suitable.