根据2009年6月巢湖32个样点的实测数据,分析巢湖水体各组分的吸收、后向散射特性以及水体漫衰减系数光谱特征,并通过Lee模型计算各影响因子对漫衰减系数的贡献率,在此基础上,进一步探讨巢湖水体漫衰减系数与各衰减因子浓度的关系.结果表明,非色素颗粒物、有色可溶性有机物(CDOM)吸收均随着波段增加呈现不断衰减趋势,400~660 nm范围内,色素颗粒物吸收的贡献率较平稳,在675 nm处由于色素强吸收,其贡献率在该处形成峰值,此后迅速下降,且色素颗粒物吸收贡献率与非色素吸收贡献率呈现此消彼长的趋势,纯水吸收的贡献率则随着波长不断增加,682 nm以后成为漫衰减最重要影响因子,颗粒物后向散射的贡献率先增大,在571 nm处达到最大,之后贡献率不断减小并维持第二主导因子地位.漫衰减系数与主要衰减因子浓度的相关分析显示,漫衰减系数与悬浮物中无机颗粒物的相关性最好,其次是有机颗粒物,与叶绿素a的相关性较差,532 nm处漫衰减系数与色素颗粒物、非色素颗粒物以及aCDOM(440)等衰减因子浓度的相关关系好于440 nm、676nm、735 nm等波段.
According to the in situ data of 32 sampling sites which were measured in June 2009,absorption,backscattering properties of different components and the spectral characteristics of diffuse attenuation coefficient(Kd) were analyzed in Chaohu Lake.And then the contribution of each factor's affecting on Kd were calculated by Lee Model.Based on the analysis,the relationship between Kd and the affects were discussed.The result indicate that: the contribution to Kd of nonpigment suspended matter and chromophoric dissolved organic matter(CDOM) absorption presented an exponent decreasing trend with the increase of wavelength;from 400nm to 660nm,the contribution of phytoplankton absorption was stable,and for the phytoplankton strong absorption,the contribution had a peak value at 675nm,and then rapidly decreased,the contributions of phytoplankton absorption and nonpigment suspended matter absorption have a relationship of restricting each other;the contribution of water absorption which increased with wavelength was to be the leading contribution factor after 682nm;the contribution of suspended particle backscattering increased till 571nm,after that it decreased and sustained at the second leading factor.The analysis of diffuse attenuation coefficient and its' affecting factors showed that the correlation between Kd and inorganic particulate matter has the best correlation,organic particles followed,and the worst was chlorophyll a.The relationship between Kd(532)and the concentration of pigment particles,non-pigment particle and aCDOM(440) was higher than Kd(440),Kd(676) and Kd(735).