| 摘要: |
| 使用水平二维对流-扩散型水交换模式模拟研究了象山港的水交换，对不同区域的水交换控制机理作了初步探讨。象山港水交换状况与其控制机制的区域性变化很大。牛鼻水道至佛渡水道是一个潮流较强的潮通道，90％水交换周期为5天左右。象山港狭湾内水交换周期较长，湾顶处90％水交换的周期约为80天左右。 |
| 关键词: 水交换 数值模拟 象山港 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金资助项目，48907026号 |
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| NUMERICAL STUDY OF WATER EXCHANGE IN XIANGSHANGANG BAY II. MODEL APPLICATION AND WATER EXCHANGE STUDY |
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DONG Li-xian,SU Ji-lan
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Second Institute of 0ceanography State Oceanic Administration, Hangzhou, 3lO0l2
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| Abstract: |
| The Xiangshangang Bay is narrow and semi-enclosed, with a mean depth of around 10m and a water area about 536km2. The bay consists of Niubi Channel, Fodu Channel and Xiangshangang Inlet. The water exchange in Xiangshangang Bay is studied with the advection-diffusion numerical model. The spatial grid size is 250m, and the measured sea surface elevation is assigned on the open boundary. The initial tracer concentration in the bay is set to 1 in the modeling domain, and the concentration value is set to 0 on the open boundary when there is inflow. The dispersion coefficients caused by the gravity circulation and the vertical shear effect in the advection-diffusion tracer model are determined by the flux analysis result of measurement data. The modeling currents are compared with the measured data at 40 stations. The difference between the calculated and observed longer axis of M2 tidal current ellipses is less than 0.05m/s, with the largest phase difference less than 5° at 80 percent of the stations.
The result shows that the water exchange rate and its mechanism differ from place to place in the Xiangshangang Bay. The area from Fodu Channel to Niubi Channel is a tidal passage near the open boundary with strong currents. The water in the passage is well mixed the sea water by advection. The period of 90 percent water exchange is only about 5d.
The tidal currents are the strongest in the outer part of the Xiangshangang Inlet. The water near the mouth of Xiangshangang Inlet can flows to the outside of the Inlet during the ebb tide. The closer the mouth of the Xiangshangang Inlet, the larger of the rate of water mixing with the water outside the Inlet. There is a sharp water exchange rate gradient near the mouth of Xiangshangang Inlet.
The inner part of Xiangshangang Inlet is narrow with weak tidal currents. Although the longitudinal mixing effects caused by the gravitational circulation and the vertical shear effect are evident, the longitudinal mixing is weak in the area. The period of water exchange is much longer than outside of the Inlet. Towards the Inlet, the water exchange period increase. The period of 90 percent water exchange is about 80d near the bayhead areas of the Inlet. |
| Key words: Water exchange, Numerical modeling, Xiangshangang Bay |
