长江口外海水中有色溶解有机物（CDOM）的光吸收特性

基于2008年5、11月2次调查数据,研究了长江口邻近海域水体有色溶解有机物（CDOM）的光吸收特性及其时空分布特征,探讨了CDOM含量、光谱斜率Sg值及其与特征波长下吸收系数a（440）的关系.结果表明,春季该海域有色溶解有机物的吸收系数a（440）的范围为2.232~8.671 m-1,平均值为4.523 m-1;秋季其吸收系数a（440）的变化范围为0.390~6.135 m-1,平均值为2.209 m-1.该水体CDOM吸收曲线基本呈指数衰减趋势.在400~440 nm波段内,春季其光谱斜率Sg值范围为0.002 0~0.014 2 nm-1,平均值为0.008 7 nm-1秋季的介于0.020 8~0.052 6 nm-1之间.平均值为0.037 5 nm-1.同时有色溶解有机物吸收系数a（440）与Sg值存在着较显著的负相关关系.

Optical absorption properties of chromophoric dissolved organic matter in the seawater of outer Yangtze Estuary

The optical absorption properties and spatial and temporal distribution characteristics of chromophoric dissolved organic matter（CDOM） in the seawater of outer Yangtze Estuary were investigated based on data collec-ted during May and November of 2008.The CDOM concentrations a（440） and spectrum slope（Sg） were analyzed and the relationships between them were discussed.The results showed that a（440） varied obviously from 2.232 to 8.671 m-1,with an average value of 4.523 m-1 in spring,and from 0.390 to 6.135 m-1,with an average value of 2.209 m-1 in autumn.CDOM absorption exhibited an exponential decay curve.Additionally,the spectrum slope,Sg,ranged from 0.002 0 to 0.014 2 nm-1 within the 400～440 nm band,with an average value of 0.008 7 nm-1 during spring,and from 0.020 8 to 0.052 6 nm-1 with an average value of 0.037 5 nm-1 in autumn.Finally,a negative correlation was found between Sg and a（440）.