钱塘江河口涌潮传播速度研究

为分析钱塘江河口涌潮传播速度的时空规律及其影响因素,应用从一维连续方程和动量方程出发推导的涌潮传播速度计算公式分析涌潮传播速度的影响因素,并将其应用于钱塘江河口涌潮的计算,结果表明与实际情况吻合良好.利用实测资料分析了钱塘江涌潮传播速度的变化规律及影响因素,与计算公式的分析结果相一致.影响涌潮传播速度的因素主要有下游潮差、江道地形和径流流量,其月内变化主要受下游潮差变化的影响,此外在一定程度上还受到上游径流量的影响.在年际尺度上,则主要取决于河床地形的冲淤变化.应用解析算法和常规水文资料建立的涌潮传播速度计算方法简单易行,可较好地应用于涌潮到达时间的预报.

Study on propagation speed of tidal bore on Qiantang River

The temporal and spatial characteristics and controlling factors of the propagation speed of the tidal bore on the Qiantang River were researched.The analytical formula for the propagation speed of the tidal bore,derived from the 1-D continuity and momentum equations,was taken advantage to analyze the impact factors of the propagation speed of the tidal bore,and to calculate the propagation speed of the Qiantang Bore.The results showed that the calculated propagation speed agreed well with the measured data.Field data were used to analyze the evolution rules and impact factors of the propagation speed of the Qiantang Bore.The results were consistent with those from the analytical formula.The propagation speed was mainly controlled by tidal amplitude at downstream,bathymetry of the estuary and river discharges at upstream.In one month,it was mainly influenced by tidal amplitude at Ganpu.In addition,the speed was impacted by the river discharges to a certain extend.In the time scale of years,the speed was mainly influenced by the river volume.The model for the propagation speed of tidal bore based on the analytical formula and conventional hydrologic monitoring data is simple and practicable and can be applied to forecast the time of Qiantang bore arriving.