长江河口潮波特征的年内变化分析

Analysis on the monthly change of the tidal wave characteristics in the Changjiang River Estuary

中文关键词:  长江口  潮汐  潮差  径流  

英文关键词:Changjiang River Estuary  tidal wave  tidal range  river discharge

中文摘要:

      对于径流变化明显的大型河口,其入射潮波受到径流季节性变化的显著影响。以往多关注洪枯季的特征对比,对年内变化过程的讨论还不充分。本文以长江河口潮波为例,基于潮区界以下多站位年内连续的实测逐时潮位资料,分析了潮差及其衰减速率、涨落潮历时等参数的时空变化特征,认识到长江河口潮波沿程特征除洪枯季差异外,还存在显著的逐月变化差异,重点关注镇江到江阴的过渡段,认识到三江营到魏村闸段在低径流月份的平均潮差衰减速率远低于其相邻上下段,仅为其三分之一。涨潮历时从河口段向近口段的递减存在拐点,到了江阴附近后,不再线性减小。并从典型径流量、沿程差异、河宽束窄等角度分析原因。

英文摘要:

      For large estuaries with obvious changes in runoff, the incident tidal waves are significantly affected by seasonal changes in runoff. In the past, much attention was paid to the comparison of the characteristics of the flood and dry seasons, and the discussion on the change process during the year was not sufficient. This paper takes the tidal wave of the Changjiang River Estuary as an example, and analyzes the temporal and spatial variation characteristics of the tidal range and its attenuation rate, ebb and flow duration and other parameters based on the continuous measured time-to-day tidal level data at multiple stations below the tidal zone boundary. In addition to the differences in the flood and dry seasons, the tidal wave characteristics also have significant monthly changes. The focus is on the transition section from Zhenjiang to Jiangyin. It is recognized that the average tidal range attenuation rate in the low runoff months is far from Sanjiangying to Weicunzha. Lower than its adjacent upper and lower sections, only one-third of it. There is an inflection point in the decrease of the high tide from the estuary section to the near-mouth section. When it reaches the vicinity of Jiangyin, it no longer decreases linearly. And analyze the reasons from the perspectives of typical runoff, differences along the way, and narrow river width.