气象海啸的诱发机制及预报方法研究

Meteotsunamis are tsunami-like waves mainly induced by atmospheric pressure disturbances. Destructive meteotsunamis are often the result of a fast moving pressure disturbance with the combination of Proudman resonance, harbor resonance, and some other wave amplification effects. This makes it more complex and difficult to be predicted. Getting better understanding of the meteotsunami phenomenon and developing prediction method is of great academic significance and application value to coastal disaster prevention and mitigation. The aim of this project is to improve the understanding of the forced wave caused by air pressure disturbance and its evolution in coastal areas, to find out the key features of the air pressure disturbances that cause destructive meteotsunamis, and further to develop a new prediction method for destructive meteotsunamis. A laboratory experiment will be carried out to study the wave pattern and growth process that caused by a moving low pressure with different distribution. A numerical model will be also developed for simulating water waves induced by air pressure disturbances. A series of idealized cases will be studied to help understanding the evolution and resonance of waves induced by pressure disturbance in specific topography, and to discuss the effects of wave nonlinearity, dispersivity, and some other factors on wave amplification in specific resonance phenomenon. Historical meteotsunami events and their corresponding meteorological data will be analyzed to identify the characteristic of pressure disturbance, and to find a way to obtain the characteristic parameters of the pressure disturbance from the complicated meteorological data. Based on the Monte Carlo method, a number of scenarios with parameterized pressure disturbances crossing over a specific region of China seas will be simulated, the risk of meteotsunami in the coastal region will be evaluated, and based on the database of numerical results, a simple prediction model using the public weather forecast data will be developed. Hopefully, early warning of meteotsunamis in the coastal area of China can be achieved with the model.

气象海啸是由大气扰动引发的类似海啸的海面水位波动现象，其致灾一般是快速移动的气压扰动引起的水波在多种共振效应下放大的结果，成灾机制复杂，预测预报也相对困难。深入认识气象海啸生成和发展的物理机制，探索预测预报方法，对沿海防灾减灾具有重要学术意义和应用价值。本项目旨在探明气压扰动引起的强迫水波的成长机制及其在近岸各种特征地形条件下演进和发展的规律，找出诱发灾害性大振幅气象海啸波的海面大气压强扰动运移变化的关键特征，发展能够高效且准确预测预报气象海啸的方法。本项目主要研究内容包括：气压扰动引起的强迫水波的波动形态和成长机制、典型海岸地形对气压扰动强迫水波的放大机制、气象海啸生成的天气模式的分析和致灾气压扰动特征参数化、气象海啸预测预报方法研究和应用。项目研究主要基于理论分析和数值分析，辅助以实验室试验和资料调研分析开展。项目成果预期可为提高我国海岸灾害预报水平提供理论和技术支持。

气象海啸是快速移动大气扰动引发的类似海啸的海面波动现象，广泛出现于世界各地沿海，是海岸地区一个不可忽视的灾害问题。研究其致灾机理和预报方法有助于海岸防灾减灾水平的提升。本项目的主要研究成果包括：1）给出了开敞海域气压扰动强迫波的形态特征和发展规律，明确了气压移动速度与波速之比对气象海啸产生的关键作用；2）揭示了气压扰动强迫波的能量积累过程，发现不同气压移动速度下能量积累和传递表现为极不相同的模式；3）指出短历时的大气扰动不能激发显著水面波动，给出了水面波动成长时间的度量参数和控制因素；4）明确了气压扰动向岸移动产生的波动特征和发展规律，指出了斜坡上强迫波发展的迟滞效应；5）给出了气压移向对近岸水波的影响，揭示了沿岸运动扰动的危险性；6）明确了沿岸扰动诱发显著边缘波的大气扰动特征参数和时间参数；7）揭示了岛屿对水波能量捕获的多重机制，给出了岛屿地形下边缘波共振预测的公式；8）揭示了沿岸移动大气扰动诱发港湾大幅振荡的一种可能机制，给出了诱发大幅港湾振荡的大气扰动特征参数和条件；9）明确了大气扰动移动方向对诱发港湾共振的影响，揭示了最危险情况发生在大气扰动以小角度登陆海岸；10）明确了气压扰动登陆点及作用时长对港湾共振的影响；11）历史气象海啸事件的再现分析，揭示了我国中东部沿海‘怪潮’也能是气象海啸；12）发展了基于雷达图像处理提取大气扰动特征参数的方法，用以参数化预测预报气象海啸。.在本基金的资助下，截至目前发表学术论文15篇，获得软件著作权1项。项目成果增进了气象海啸致灾机理的一些认知，明确了在海岸诱发显著水位波动的大气扰动主要参数以及致灾的条件，并基于雷达图像分析开发了大气扰动主要参数获取方法，设计了气象海啸预测预报的参数化方法，研究成果可为海岸防灾减灾提供支持。