| 摘要: |
| 根据1979–1992年不同类型淤泥质潮滩涨潮前锋水沙观测资料，结合潮锋作用沿滩面上溯的强度变化进行分析。结果表明，涨潮前锋存在水流加速过程是潮锋作用的本质，其出现前提是滩面的宽展平缓，而潮位变化速率过程则决定了潮锋作用强度及其时空变化。潮锋带水体的高含沙量现象及其沿程变化在潮滩滩面发育中具有重要意义。 |
| 关键词: 淤泥质潮滩 潮锋带水流加速效应 潮位变率 滩坡 发育模式 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金资助项目，49106060号 |
附件 |
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| THE IVIECHANISM AND SIGNIFICANCE OF FLOOD SURGE ALONG MUDDY TIDAL FLAT |
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XU Yuan,WANG Bao-can
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Institute of Coastal & Estuarine Research, East China Normal University , Shanghai, 200062
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| Abstract: |
| Based on the results of previous investigations in l979-l992, this paper describes processes of the tidal current effect on muddy tidal flats, including the effects of tidal surges and the post-surge tidal currents. A mechanism for the formation of the flood surge is shown to be the current acceleration over the flood tidal surge zone, which is associated with pulse current velocity being about 2.5 times of a mean current velocity. Such a hypothesis was examined using detailed observation data representing dynamic characteristics of the currents and sands on tidal flats of different types such as harbor-plain, estuary-bay, estuary-shoal and open sea types. It is theoretically deduced that a premise for the formation of flood surges is a small slope of tidal flats. The rate of the change in the local tidal level governs the spatial and temporal changes in the flood surge strength. Thus, the phenomenon of high suspended sediment concentration in the flood surge zone and its variation over the tidal flat can be explained. The processes associated with the tidal surge and the post-surge tidal current are determined by the characteristics of the local tidal wave; the tidal flat can be dominated by the progressive and the standing tidal waves. For the former the accretional -erosional pattern of the tidal flat is represented by accretion over the high tidal flat, upper, and lower parts of the middle tidal flat and the low tidal flat, whereas the central part of the middle tidal flat is in a balanced situation in terms of accretion and erosion. For the latter, the rate of accretion is the highest over the middle tidal flat; it decreases over the low tidal flat and is the lowest over the high tidal flat. |
| Key words: Muddy tidal flat, Current accelerating effect in flood surge zone, Change rate of tidal level, Tidal flat slope, Development model |
