Recognition of Tide and Tidal Current Movement in the Yangtze Estuary

通过对潮位、比降、流速周期性变化内在关系的分析，揭示了长江口河段潮位、潮差、比降变化与径流之间的宏观关系。研究结论认为：长江口平均潮位向海沿程降低，比降沿程减小，年平均潮差逐渐增大，至牛皮礁站附近达到最大，体现了径流与潮汐动力强弱变化的过程。通过对潮差的研究，发现长江口潮差变化的分区界限，其上下遵循不同的规律，而且这个界限随径流的增大而下移，小水年在白茆~杨林之间，大水年在石洞口~高桥之间。通过对比降以及比降和潮流速周期之间的关系研究，揭示了由于径流的惯性作用，使得潮流的变化滞后于比降的变化。这些研究结论在河道治理及航道整治中，对长江口不同的区段采取不同的治理方案具有指导意义。 Based on the analysis of the relationship between the tide level, the specific gradient and the periodic variation of the flow velocity, the study concluded that: The average tide of the Yangtze River estuary is decreasing along the path; the slope is decreasing along the way; the average tidal range increases gradually, to reach the maximum station near the cowhide reef, which reflects the process of runoff and tidal power change. Through the study of the Yangtze River Estuary tidal range, it found that the Yangtze River Estuary tide follows different rules and variable partition boundaries, and the limit decreases with increasing runoff. The boundaries located between Baimao and Yanglin stations in flood years, and located between Shidongkou and Gaoqiao stations in dry years. Through comparative research on the relationship between the slope and tidal velocity cycle, which reveals the change of trend lags behind the change of slope due to the inertia the runoff. These conclusions are of guiding significance for different channel sections of the Yangtze River in the channel regulation and channel regulation.