| 摘要: |
| 陆架陷波(Coastal trapped waves, CTWs)的发生会造成沿岸水位异常增长，是引发大范围海水倒灌灾害的重要原因之一，因此探究CTWs的发生规律及其调控机理有利于我国海水倒灌灾害预警报工作的开展。渤、黄海作为陆架宽阔的半封闭边缘海，是CTWs的高频发生海域，因而该海域是开展CTWs研究的绝佳区域。本文通过渤、黄海2021-2025年海洋站逐时水位观测资料，定量分析了CTWs与海平面高度异常(SLA)的关系，构建了准确率达99 %的CTWs发生预报模型。在此基础上，结合FVCOM模式的风场控制实验，我们首先阐明了低（高）SLA条件有利于（抑制）CTWs的物理机制:引发渤、黄海沿岸水位显著变化的CTWs主要包含Kelvin波(Kelvin wave, KW)和风强迫的低模态陆架波(wind-forced low-mode shelf wave, WLSW)，较低的SLA利于KW生成，并有助于WLSW传播，因此有利于CTWs引发沿岸增水。另外，本文基于数值模式试验结果证明了CTWs发生时增水强度与背景风场分布形态与作用时长之间的潜在联系:KW主要由北风引起的南北海平面高度差所形成的压强梯度力驱动，WLSW则由朝鲜半岛沿岸顺岸偏东风强迫生成，风速与作用时长均与KW和WLSW的增水幅度呈正相关；同时二者可通过耦合作用显著增强CTWs引发的沿岸增水幅度，进而加剧沿海灾害强度。 |
| 关键词: 渤、黄海 陆架陷波 海水倒灌 预报模型 |
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| 基金项目:山东省自然科学基金；国家重点研发计划；崂山实验室“十四五”重大项目;上海市海陆气界面过程与气候变化重点实验室开放课题 |
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| STORM SURGE MECHANISM AND FORECASTING MODEL OF COASTAL TRAPPED WAVES IN THE BOHAI AND YELLOW SEAS |
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Gao Jing1, Li Jian1, Liu QingRong1, Gao Song1, Zhang Zhixiang2
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1.North China Sea Marine Forecast and Hazard Mitigation Center, Ministry of Natural Resources;2.Institute of Oceanology, Chinese Academy of Sciences
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| Abstract: |
| Coastal trapped waves (CTWs) can trigger abnormal rises in coastal water levels and constitute one of the major causes of large-scale seawater inundation. Investigating the occurrence characteristics and regulatory mechanisms of CTWs is therefore conducive to the development of early warning and forecasting systems for seawater inundation in China. As a semi-enclosed marginal sea with a broad continental shelf, the Bohai and Yellow Seas are regions with frequent CTW events, providing an ideal laboratory for CTW research. Based on hourly water level observations from tidal gauge stations in the Bohai and Yellow Seas during 2021-2025, this study quantitatively analyzed the relationship between CTWs and sea level anomalies (SLA), and established a CTW occurrence prediction model with an accuracy of 99%. Furthermore, combined with wind-perturbation sensitivity experiments using the FVCOM model, we first clarified the physical mechanism by which low (high) SLA favors (suppresses) CTWs. The CTWs responsible for remarkable coastal water level fluctuations in the Bohai and Yellow Seas mainly consist of Kelvin waves (KW) and wind-forced low-mode shelf waves (WLSW). Low SLA promotes the generation of KW and facilitates the propagation of WLSW, thereby enhancing coastal water level rises induced by CTWs. Further analysis combined with numerical experimental results verified the potential linkage between the intensity of water level rises during CTW events and the spatial pattern as well as duration of background wind forcing. KWs are primarily driven by the pressure gradient force arising from the north-south sea level difference induced by northerly winds. The WLSWs are generated by easterly winds along the coast of the Korean Peninsula. Both wind speed and forcing duration are positively correlated with the amplitude of water level rises associated with KWs and WLSWs. Moreover, the coupling of these two kinds of wave can substantially amplify coastal water level rises induced by CTWs, further exacerbating the severity of related disasters. |
| Key words: Bohai and Yellow Seas ? Coastal Trapped Wave ? Seawater Inundation ? Forecasting Model |