珠江三角洲河网与河口夏季水沙通量模拟研究

本文利用一、三维水动力与泥沙耦合模型，计算珠江三角洲河网与河口夏季水沙通量，构建其收支模式，并分析水沙迁移路径与泥沙沉积特征。研究表明，西江为最主要的水沙输入源，磨刀门为最主要的水沙输出口门，蕉门次之。夏季泥沙以淤积为主，上游汇入的泥沙，有39.4%沉积于河网区，其余60.6%经八大口门输入珠江口后，有59.5%发生沉积，另外1.1%输入外海。河网区的水沙输送由径流控制，而河口区的由径流、潮汐、季风等因素控制。河网区各区域的沉积特点因动力条件的差异而呈现不同的规律，大量泥沙在西江干流、虎门水道淤积。珠江口中以内伶仃洋与磨刀门海域的沉积量最大，泥沙在西滩周边和磨刀门海域快速沉积，其中磨刀门海域淤积最为强烈。

Modeling Water and Suspended Sediment Fluxes in the Pearl River Delta during Summer

A 1-D and 3-D coupled physical-sediment model is applied to calculate water and suspended sediment (SS) fluxes in the Pearl River Delta (PRD) and construct their budgets for the entire region. Transport of water and SS and deposition of SS are also discussed in this study. Results show that Xijiang River dominates the fluvial inputs of water and SS to the River-Network in the PRD (RNPRD), while Modaomen is the largest output among the eight river outlets, followed by Jiaomen. Deposition is the dominant process for SS during summer, resulting in a loss equivalent to 39.4% of the fluvial inputs of SS in the RNPRD. The rest are exported to the Pearl River Estuary (PRE) through the eight outlets. Loss via deposition in the PRE consumes 59.5% of the fluvial inputs, leaving 1.1% escaped to the South China Sea. The water and SS fluxes in the RNPRD are dominated by strong river discharges, while those in the PRE are controlled by multiple forcing mechanisms including river discharges, monsoon winds and tides, etc. The characteristics of deposition for different areas in the RNPRD, which are related to their hydraulic conditions, distinguish from each other. Large deposition occurs in the Xijiang mainstream and Humen channel in the RNPRD. Regarding the PRE, zones with the largest deposition are located in the Inner Lingdingyang and the Modaomen bay. High deposition rates are found to occur around the West Shoal Island and the Modaomen bay which is recognized as the most acute deposition zone in the PRE.