三峡工程一期蓄水后长江口及其邻近海域悬浮物浓度分布特征

长江三峡工程一期蓄水自2003-06-01开始,到2003-06-10结束.为了研究长江三峡工程蓄水对长江口环境的影响,在2003-06-15～2003-06-25进行了长江口及其邻近海域环境综合调查.根据此次调查所取得的实测数据资料,计算了各站各层位的悬浮物浓度,结合相应水体的盐度值和温度值,分析了长江口及其邻近海域悬浮物浓度的分布特征以及蓄水前后悬浮物浓度与分布格局的变化.结果表明,长江口及其邻近海域悬浮物浓度自海水表面向海底逐渐增高,悬浮物主要分布在123°E以西的口门地区和近岸的狭长海区.三峡工程一期蓄水后与蓄水前长江口多年平均含沙量相比,长江航道和南支地区悬浮物浓度明显下降,长江航道徐六泾附近地区悬浮物浓度从蓄水前的400～500 mg/L下降到蓄水后的60.2 mg/L,南支地区悬浮物浓度从蓄水前的445 mg/L下降到蓄水后的148 mg/L;长江口邻近海域悬浮物浓度变化不明显,蓄水前后均为表层悬浮物浓度小于10mg/L,底层悬浮物浓度小于100 mg/L.蓄水前后整个研究区悬浮物浓度分布的总体格局相似.

Distribution of Suspended Matter Concentration in the Changjiang Estuary and Adjacent Area After the First-Stage Storage of the Three Gorges Project

The first-stage storage of the Three Gorges Project started on the 1st June, 2003 and ended on the 10th June, 2003. In order to investigate the influences of the Three Gorges Project in the Changjiang Estuary and adjacent area environment, a cruise was carried out from the 15th June, 2003 to the 25th June, 2003 to synthetically study the environment. Suspended matter concentrations (SMC) in different layers at different sites were calculated and distributions of SMC were discussed combining with salinity and temperature of water based on recovered data. In results, SMC increase from surface to bottom in Changjiang Estuary and adjacent area. Most of suspended matters are distributed on the river mouth bar and alongshore area which are located at the west of 123°E. Compared to that before the storage, SMC are reduced obviously in the Changjiang course and south branch after the storage, for example, at the XuLiujing, SMC are reduced from 400mg/L~500mg/L to 60.2mg/L, and in the south branch, from 445mg/L to 148mg/L. In other areas, SMC do not show a significant change that they are both less than 10mg/L in the surface player and 100mg/L in bottom player. Generally, the distributed patterns of SMC in the investigation area after the storage are still similar to that before the storage.