| 摘要: |
| 收集和分析了南海北部沿岸15个海洋站所在港湾发生假潮的资料,并对其中较大振幅的典型假潮个例,进行了港湾基态自然周期分析和假潮振动的频谱分析。研究发现,假潮最大振幅振动多发生在天文潮的高潮或低潮期间;根据海湾地形尺度用梅立恩(Merian)公式计算得出的海湾基态自然周期,和根据资料曲线估计得出的假潮周期,以及功率谱分析得出的周期,三者非常接近。从本文研究所得结果来看,这些海湾的较大振幅假潮多发生在春、夏季,且都和风速、风向以及气压的剧烈变化有关。这些大气扰动在春天多为冷空气南下,在夏季多为热带气旋活动。研究认为,假潮的发生很可能是大气扰动通过外海表面波作为中间机制,与港湾自由态振动之间产生耦合共振的结果。
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| 关键词: 假潮,南海北部,基态自然周期,大气扰动激发机制 |
| DOI：10.11693/hyhz200201002002 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目,49676281号 |
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| SEICHES AT THE COASTAL STATIONS ALONG THE NORTH COAST OF SOUTH CHINA SEA |
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XIA Zong-Wan, LIN Shao-Yi, WANG Yong-Xin, MAI Shao-Jun, ZHANG Jun-Feng
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South China Sea Branch,State Oceanic Administration
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| Abstract: |
| The seiche data from 15 coastal stations along the north coast of South China Sea are collected.These data,especially those of the typical seiche events with relatively large amplitude,are examined by using statistics, natural period analysis and spectrum analysis to study the mechanism. Among those 15 coastal stations,seiches with an amplitude of no less than 20cm were found in 9 of them. The average occurring frequency is from almost once per month to almost once per 33 months. These seiches occur mostly in February, March and April. Among the total 327 seiche events, there are 10 sets (or events) with amplitude greater than 50cm, and the greatest amplitude is 102cm. It is found that, the greatest amplitude of each seiche event occurs mostly during the high or low tides. The natural period of fundamental mode of the bay calculated by the Merian' s formula coincides well with the period estimated from the curve of observational water level, as well as with the period derived from the power spectrum. This result shows that the seiches with relatively large amplitudes mostly occur in spring and summer, and they are all related to rapid changes in wind speed and direction as well as air pressure. These atmospheric perturbations are south-going cold airs in spring time and tropical cyclones in summer time. This study shows that the occurrence of these seiches is likely the result of coupling and resonance between atmospheric perturbation and free mode oscillation of the bay, which has the oscillation of off-shore surface wave as an intermediate media.
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| Key words: Seiche,North coast of South China Sea,Natural period of fundamental mode,Atmospheric perturbation trigger mechanism |
