基于MIKE3的丰枯水期防城湾水交换能力研究

为了对防城湾水交换能力有全面的认识,本文基于无结构的三角网格建立高分辨率的MIKE3水动力数值模型,采用Lagrange质点追踪方法,选取水体半交换周期和水体交换律作为评价指标,评价防城湾丰枯水期水交换能力。结果表明:防城湾水交换主要受径流和潮流控制,因防城河的存在,西湾保守物质浓度的空间分布呈现由河口向湾外增加趋势,东湾的保守物质浓度的空间分布呈现由湾口向湾内增加趋势,随着时间的增加,两湾保守物质浓度下降速率降低;西湾水交换时间明显少于东湾,半交换期在丰水期为1.7d,在枯水期为3.6d;东湾在丰水期半交换时间为15.2d,在枯水期为27.8d。

Study on Water Exchange Capacity of Fangcheng Bay in Dry and Wet Season Based on MIKE3 Model

In order to have a comprehensive understanding of the water exchange capacity in Fangcheng Bay, a high-resolution MIKE3 hydrodynamic numerical model based on the unstructured triangular grid is established. Using Lagrange proton tracing method, the half exchange period and commutative law of water are selected as the evaluation indexes to evaluate the water exchange capacity of Fangcheng Bay in dry and wet seasons.The results show that the water exchange in Fangcheng Bay is mainly controlled by runoff and tide. Due to the existence of Fangcheng River, the spatial distribution of the concentration of conservative substances in the West Bay increased from the estuary to the outside of the bay, and the spatial distribution of the concentration of conservative substances increase from the estuary to the inside of the bay. With the increase of time, the rate of decline in the concentration of conservative substances in the two bays decreases. The water exchange time in West Bay is obviously less than that in East Bay.The half exchange period of West Bay is 1.7 d in wet season and 3.6 d in dry season, while the half exchange period of East Bay is 15.2 d in wet season and 27.8 d in dry season.