长江感潮河段径流对潮波变形和传播的影响研究

Influence of runoff on tidal wave deformation and propagation in tidal reaches of Changjiang River

受径、潮流相互作用,长江感潮河段潮波从河口向上游传播过程中沿程变形过程复杂。基于长江感潮河段实测高、低潮位,潮时资料以及大通站日均流量数据,采用数理统计、Hermit插值和小波分析方法,分析了长江感潮河段潮汐特征值和潮波传播特征值随流量的变化关系。结果表明:高、低潮位及平均水位随流量增大而增大,并且越往下游对流量的敏感度越低;江阴以上河段潮差随流量增大而先减小后增大;径流对分潮振幅的影响在江阴以上河段较明显,半日潮和全日潮振幅随流量增大先减小后增大,1/4日分潮振幅随流量增大而减小,其中半日潮振幅变化幅度最大;平均水位坡度在芜湖-马鞍山段随流量增大而先增大后减小,在马鞍山以下河段与流量呈正相关;潮波振幅衰减率随流量增大而先增大后减小,越靠近入海口,流量阈值越大。研究成果有助于深入认识河口径潮相互作用机制,亦可为河口治理提供参考。

Due to the interaction of runoff and tidal current,the deformation process of tidal waves along the tidal reach of the Changjiang River is complicated during the propagation of tidal waves from the estuary to the upstream.In this paper,based on the measured data of high and low tidal levels and tidal time in the tidal reach of the Changjiang River and the daily average flow data at Datong station,the relationship between tidal eigenvalues and tidal wave propagation eigenvalues with flow in the tidal reach was analyzed by mathematical statistics,Hermit interpolation and wavelet analysis.The results showed that the high,low tide level and average water level increased with the increasing of flow rate,and the more far to the downstream,the lower the sensitivity to flow rate was.The tidal range of the upper reaches of the Jiangyin reach decreased first and then increased with the increase of flow rate.The influence of runoff on the amplitude of tidal constituents was more obvious in the upper reaches of Jiangyin Station.The amplitude of semi-diurnal tide and diurnal tide decreased first and then increased with the increase of discharge,and the amplitude of quarter-day tidal constituents decreased with the increase of discharge,among which the amplitude of semi-diurnal tide changed the most.The average water level slope increased first and then decreased with the increase of flow rate in Wuhu-Ma′anshan reach,however it was positively correlated with the flow rate in the lower reaches of Ma′anshan Station.The attenuation rate of tidal wave amplitude increased first and then decreased with the increase of flow rate.The closer to the estuary,the greater the flow threshold was.The research results are helpful to understanding the mechanism of tidal interaction in river mouth,and can also provide scientific guidance for estuary management.