珠江河口拦门沙演变对咸潮上溯的影响

Research on the Influence of Evolution of Sand Bar in the Pearl River Estuary on Saltwater Intrusion

河口拦门沙处于河流与海洋交汇作用的关键地带,其沙河床演变对咸潮影响剧烈。利用实测水深与河流岸线数据及NOAA的海岸线数据,构建了基于FVCOM磨刀门盐水入侵数值模型,研究了拦门沙河床演变对河口地区咸潮上溯的影响。结果表明,构建的基于FVCOM盐水入侵数值模型具有较好模拟效果,典型测站水位验证相关性系数高于0.94,盐度验证相关性系数高于0.83,能够较好反演咸潮上溯过程;拦门沙每深1.5m,距离河口15km内平均含氯度约增加600mg/L,上溯距离约增加1km;距离河口23km内平均含氯度约增加252mg/L,上溯距离约增加500m;对距离河口25km以外地区影响较小,可忽略。

The sand bar in the estuary area is the key part of the river entering the sea,its changes of water and sediment and river bed changes are drastic,which has obvious impact on the saltwater intrusion in the estuary area.In this paper,using the river data from the Hydrological Yearbook and the NOAA coastline data,the Modaomen saltwater intrusion numerical model is constructed based on FVCOM,and the study on the impact of the topographical change of the sand bar in the Pearl River estuary on the uptrend of saltwater intrusion is carried out.The water level verification correlation coefficient is higher than 0.94,and the salinity verification correlation coefficient is higher than 0.83,which can better invert the saltwater intrusion uptracking process.For every 1.5 mdeep of the sand,the average chlorine content within 15 km from the estuary increases by about 600 mg/L,the uptrack distance increases by about 1 km.The average chlorine content within 23 km from the estuary increases by about 252 mg/L,and the uptrack distance increases by about 500 m.The impact on areas beyond 25 km from the estuary is small and can be ignored.