东碇倾倒区疏浚泥悬沙输移和海床冲淤数值模拟

摘要

采用区域海洋模型ROMS （Regional Ocean Modeling System）在东碇倾倒区建立三维水动力与泥沙输移数值模型，在水动力验证的基础上模拟预测了在冬、夏季节不同背景潮流和风场作用下的疏浚泥悬沙输移规律及海床沖淤变化。结果表明：在纯潮流作用下，悬沙扩散以抛泥点为中心，呈圆对称分布，且冬季泥沙输移扩散范围比夏季大；加入风场驱动后，悬沙扩散呈下风面拖拽的椭圆形，同时水体混合加强更有利于高浓度悬沙的扩散，但对悬沙输移的作用不明显；抛泥点位置从倾倒区中心变为西北角后，其作用主要体现在冬季较高浓度区面积的减小和由于局地水槽引导而形成的向北延伸的浓度舌；在海床冲淤方面，潮流和风场的作用主要是改变地形增量较大的面积，而更改抛泥点位置则会导致地形增量最大值出现较大的差异。%A three-dimensional hydrodynamic and sediment model for Dongding dumping area outside the Xiamen Bay is established by using ROMS ( Regional Ocean Modeling System). On the basis of the model verification with the observed data, we simulate the transport and erosion of the dredged sediments, driven by different tidal currents and wind fields of winter and summer. The result shows:if the model is only driven by the current field, the suspended sediment distributes evenly with a circular pattern around the dumping point, and diffuses wider in winter than in summer. When the wind field is added, the suspended sediment distributes elliptically on the leeward side, and the strong mixing of the water can enhance the diffusion of the suspended sediments with high-concentration, but it has no evident action on the transport of the sediments. When the dumping point moves to the northwest corner of the domain, the area of high-concentration decreases and a northward tongue of gradient concentration is formed, attributing to the gradient of the adjacent channel. In general, the distribution pattern and the area of sedimentation are mainly dominated by the tidal current and wind fields, while the maximum value of sedimentation depends on the position of the dumping point.