太湖有色溶解有机质光谱吸收空间的分异特征

Mechanisms and characteristics of spatial distribution of coloured dissolved organic matter in Taihu Lake between summer and winter

利用模糊聚类的方法,分析了冬、夏季全太湖有色溶解有机质(CDOM)的吸收系数谱的时空演变特征.结果表明,就太湖CDOM的组成而言,冬、夏2季的CDOM均可大致划分为2类,夏季,一类位于太湖西部沿岸及北部湾区,另一类位于太湖东南部区域;冬季,其一位于太湖北部及北部湾区,其二位于太湖的南部.太湖北部区域入湖河道输送的有机物是造成该区域CDOM的组成类型及浓度区别于太湖南部的主要因素.冬、夏2季不同盛行风引发的风生流,是造成CDOM在太湖呈现不同季节、不同空间分布的基本原因.在这2季中,北部湾区的CDOM的浓度均大于其南部区域,且南部CDOM浓度的空间变化较北部平缓.冬季全太湖CDOM组成的空间变化较夏季更为均匀.

Characteristics of coloured dissolved organic matter （CDOM） between the summer and winter in Taihu Lake were analyzed using an fuzzy clustering method. In terms of the spectral absorption shape of CDOM, there were approximately two species in different seasons. During the summer one specie was located in the western coast and the upper bay of Tailau Lake. The other one occured mainly in the southeast of the Lake. In the winter, patterns of species were different with one located in the upper of Taihu lake and the other one located in the south in winter. Mechanisms to cause the sptial difference of CDOM were investigated. Organic materials transported from the northwest rivers led to the difference of components and the concentration of CDOM. Wind-driven current by monsoons in different seasons also played an important role in controlling the spatial and temporal distribution of CDOM in Taihu Lake between summer and winter. The concentration of CDOM in the northwest bay was larger than that in southeast, and the changes of CDOM concentration in sampling location in southeast was smaller than that in northwest bay. Spatial variation of CDOM in the summer in the southeast was more uniform than that in the winter in the northwest