象山港水交换特性研究  

Study on the features of water exchange in Xiangshangang Bay

作　　者：彭辉[1] 姚炎明[1] 刘莲[2] 

机构地区：[1]浙江大学港口海岸与近海工程研究所,浙江杭州310058 [2]国家海洋局宁波海洋环境监测中心,浙江宁波315040

出　　处：《海洋学研究》2012年第4期1-12,共12页Journal of Marine Sciences

基　　金：国家海洋公益性行业科研专项经费资助项目(201105009);象山港海域海洋环境质量综合评价方法(DOMAP(MEA)-03-02)

摘　　要：在验证良好的三维斜压潮流数学模型的基础上,以溶解态的保守性物质为示踪剂,建立对流-扩散型的海湾水交换数值模型,计算了象山港水体半交换时间和平均滞留时间,并研究了斜压动力对湾内外水交换的贡献。研究结果表明,象山港水交换速度的区域性变化较大,水体半交换时间和平均滞留时间由象山港口门向湾顶逐渐增加,口门附近半交换时间在5d以内,平均滞留时间为5～10d;湾顶水交换速度缓慢,水体半交换时间为30～35d,平均滞留时间为35～40d。斜压动力对狭湾外段水交换影响较弱,对狭湾内段有较大的影响。The water exchange and its spatial and temporal variation in the Xiangshangang Bay were studied with an advection-diffusion water exchange numerical model. The model is based on the well-verified three- dimensional baroclinic model for hydrodynamic process and dissolved conservative material was used as the tracer. The initial tracer concentration was set to 1 mg/L inside the bay and 0 mg/L outside the bay and at the open boundaries inflow. According to the tracer concentration, half-life time and mean residence time of the water mass at different points of the bay were calculated, and the contribution of baroclinic power to the water exchange was studied by comparison with that at barotropic model. The results show that the water exchange, to the east of the Xize section, is fast with a half-life time of 5 days and a mean residence time of about 15 days. While the half-life time and mean residence time to the east of the Xihugang inlet are 15~20 days and 25 days separately. And the section near the Wusha Mountain has a half-life time of about 25 days and a mean residence time of about 30 days. Moreover, water exchange in the top of the bay is even slower, with a half-life time of 30 ~ 35 days and a mean residence time of 35 ~ 40 days in Tiegang harbor and Huangdungang harbor. The result shows that, both the half-life time and mean residence time increase gradually from the mouth to the top of the Xiangshangang Bay, suggesting the water exchange rate and governing mechanism differ spatially in the Bay. The region between the mouth of the bay and Xize is an area of strong tidal current, where the water flows out with the ebb current and mixes with the water outside, then flows back into the bay with flood current. So the exchange rate here is quite high, and the water closer to the mouth is mixed more fully. However, the inner part of the Xiangshangang Bay is dominated by gravitational circulation and tidal oscillation, where the mixing is much weaker and the period of water exchange is much longer than that in th

关 键 词：象山港 水交换 斜压 半交换时间 平均滞留时间 

分 类 号：P731[天文地球—海洋科学]