长江口海域污染物入海扩散模拟研究

Numeric Simulations of the Pollutant Diffusions of Sewage Outfalls in the Yangtze River Estuary

长江口地形复杂,水动力过程也极为复杂,模拟污染物的三维扩散也十分困难。本文基于三维海洋模型FVCOM和示踪剂扩散技术,模拟上海市石洞口、竹园、白龙港和新和4大排污口的污染物质在长江口的扩散分布,分析污染物在水体表层、中层、底层的扩散特性及其影响范围。研究表明长江口污染物的扩散在垂向上分布差异不大,在长江口内污染物由于受到长江径流影响较大,虽然水平分布存在往复运动的现象,但总体趋势是向长江口扩散的。当污染物流出长江口以后,受潮流的影响较大,逐渐向外海扩散,最终部分污染物会扩散进杭州湾,排污口的污染物质会对排污口沿岸、上海中华鲟自然保护区上海九段沙湿地国家级自然保护区造成生态影响,对上海市的饮用水源地不会造成影响。

There is complex topography in the Yangtze River Estuary （YRE）, where hydrodynamicprocess is also extremely complex. It is difficult to simulate three-dimensional pollutants diffusion inthe YRE. In this paper, based on three-dimensional ocean model （FVCOM） and the tracer trackingtechnology, simulated the pollutant diffusions of sewage outfalls （Shi Dongkou, Zhu Yuan, Bai Longgang, and Xin He） in the Shanghai, analyzed of pollutants diffusion characteristics and influence scopesin the surfaces, middle, bottom layers in the YRE. The results showed that there is not obvious difference in vertical distribution of pollutants diffusion in the YRE. Due to greater effect of Yangtze Riverrunoff on pollutants diffusion in the YRE, although horizontal diffusion distribution oscillated move-ment by tide, the overall diffusion trend is to the YRE. After pollutants diffused out of the YRE, pollutants are greatly influenced by the tide. Pollutants gradually were diffused to out to sea. Finally somepollutants can be diffused into the Hangzhou Bay. Pollutants can effect on coast nearby sewage out-falls, Chinese sturgeon nature reserve, Jiuduansha shoals wetland national nature reserve, little effecton source of drinking water in Shanghai.