中文摘要：

2009年4、6月,分别对太湖、巢湖进行了野外试验.利用光谱微分技术分析了2个湖泊CDOM吸收光谱的变化特征,根据吸收系数的光谱微分特征,对240～450nm的吸收系数进行分段,分别对每一段计算光谱斜率S值.在A段,巢湖、太湖CDOM的S值分别在：0.0166～0.0102nm^-1[平均值（0.0132±0.0017）nm^-1]和0.029～0.017nm^-1[平均值（0.0214±0.0024）nm^-1]之间,在B段,其S值分别在：0.0187～0.0148nm^-1[平均值（0.0169±0.001）nm^-1]和0.0179～0.0055nm^-1[平均值（0.0148±0.002）nm^-1]之间,在C段,其S值分别在：0.0208～0.0164nm^-1[平均值（0.0186±0.0009）nm^-1]和0.0253～0.0161nm^-1[平均值（0.0197±0.002）nm^-1]之间.结果表明：①太湖水体的吸收系数及对各组分吸收的贡献要小于巢湖水体的,标准化吸收系数要大于巢湖水体的.②不管是太湖还是巢湖,CDOM的吸收系数的微分光谱在260nm左右为谷值,在290nm左右为峰值,CDOM吸收系数可以分成（A、B、C）3段.③太湖水体中CDOM腐殖酸的相对含量整体要低于巢湖水体的.④S值反映CDOM组成的敏感性,与CDOM的组成有关,当CDOM中腐殖酸相对含量较高时,敏感性最强的是B段的S值,其次是C段的;反之,敏感性最高的是C段的,其次是A段的,最弱的是B段的.

英文摘要：

Field experiments are conducted separately in Taihu Lake and Chaohu Lake on Apr. and Jun. 2009. The changes in absorption spectra of chromophoric dissolved organic matter（ CDOM） characteristics are analyzed using spectral differential analysis technology. According the spectral differential characteristic of absorption coefficient; absorption coefficient from 240 to 450 nm is divided into different stages,and the value of spectral slope S is calculated in each stage. In Stage A,S value of CDOM in Taihu Lake and Chaohu Lake are 0. 016 6-0. 010 2 nm -1[average （0. 013 2 ± 0. 001 7）nm -1],0. 029-0. 017 nm -1[average（0. 021 4 ± 0. 002 4） nm -1]. In Stage B,S values are 0. 018 7-0. 014 8 nm -1[average （0. 016 9 ± 0. 001） nm -1 ],0. 017 9-0. 005 5 nm -1[average （0. 014 8 ±0. 002）nm^-1]. In Stage C,S values are 0. 020 8-0. 016 4 nm^-1[average（0. 018 6 ±0. 000 9）nm^-1],0. 025 3-0. 016 1 nm -1[average （0. 019 7 ± 0. 002）nm -1]. The results can be concluded as： ① Absorption coefficient of water in Taihu Lake,and its contribution to absorption of each component is less than that of water in Chaohu Lake,however the standardized absorption coefficient is larger than that in Chaohu Lake. ②Both in Taihu Lake and Chaohu Lake,derivative spectra of CDOM absorption coefficient reached valley at 260nm,then rise to top at 290 nm,CDOM absorption coefficient can be delivered into three stages. ③ Generally speaking, content of CDOM in Taihu Lake is less than in Chaohu Lake. ④Spectrum slope （ S value） of CDOM is related to composition of CDOM,when content of humic acid in CDOM gets higher,S value of Stage B is the most sensitive value,then is the S value of Stage C. Oppositely,S value of Stage B gets the most sensitive value,then is the S value of Stage A; the least sensitive value is in Stage B.