洋山港海域一次冷锋型温带风暴潮特征及各影响因子贡献的对比分析

本文研究了由2020年12月29日至31日强冷锋引起的影响洋山港海域的温带风暴潮过程。通过气象观测数据分析了其天气过程, 并利用FVCOM-SWAVE波浪-风暴潮耦合模式对该过程进行了高分辨率的数值模拟, 同时结合潮位站及浮标站观测数据对模拟结果进行了验证, 分析模拟了波浪、潮流、风暴增减水特征。结果发现, 该次冷锋型温带风暴潮过程主要表现为先短时风暴增水后出现长时间风暴减水的特征, 最大风暴减水可达65~70cm, 其主要诱因包括研究海域气压的快速升高并维持、长时间持续的偏北大风及波流相互作用。相关敏感试验研究了3种因子对风暴增减水位的贡献大小, 发现风暴增水峰值期间风场贡献占比约为90%, 海平面气压场约为5%; 风暴减水峰值期间, 海平面气压场的贡献度约占55%, 风场约占40%, 而波浪的贡献均不足10%。洋山港航道内风暴期间潮流流速最大可达到2.6~2.8m?s^-1, 落潮时为东南向离岸潮流, 涨潮时为西至西北方向的外海潮波传入潮流; 洋山港航道潮流始终是东南或西北向, 此处流速辐合, 是洋山海域流速最高的区域。

Comparative study on the contribution of various influential factors and characteristics analysis of an extra-tropical storm surge caused by cold front in the Yangshan Port and its adjacent area

In this paper, an extra-tropical storm surge in the Yangshan Port (YSP) and its coastal area caused by a strong cold front on 29th December, 2020 was investigated. Meteorological observation data was analyzed to study the development of the weather system. FVCOM-SWAVE model characterized by a high-resolution unstructured-grid with 10 m was used to simulate the storm surge. The observed tide data, wave data and current data were introduced to verify the result of simulation, and the result was proved to be accurate and credible. Maximum storm surge, maximum negative storm surge, current, total water level and wave were studied to describe the character of the extra-tropical storm surge of YSP and its coastal area. Finally, sensitive experiments were carried out to compare the contributions of mean sea level pressure (SLP), wind and wave to the maximum storm surge. The main conclusions can be summarized as follows: 1) affected by the topography of the channel, the main component of the tidal current was southeast or northwest, which was approximately parallel to the shoreline, the current velocity in the deep water channel of YSP was the highest with a value between 2.6~2.8 m·s^-1; 2) due to the influence of long term northerly gale and high SLP, the storm surge behave as a characteristics of short-term positive storm surge and long-term negative storm surge; 3) during the peak period of storm surge, the contribution of wind field to storm surge was ~ 90%, and the contribution of sea-level pressure field was approximately 5%; while during the peak period of negative storm surge, the contribution of sea-level pressure field was about 55%, the contribution of wind field was ~ 40%, In addition, the contribution of wave to both was less than 10%.