基于数值模拟的不同形态内孤立波特征研究

Research on characteristic of internal solitary wave in different forms based on numerical simulation

作为南海中频发的重要动力过程,内孤立波对水体及物质的输运具有显著影响,对南海生态环境具有重要意义。在传播过程中,内孤立波会经历形态变化,从而引起不同的生态学效应。文章基于MITgcm数值模式模拟了南海北部内孤立波的传播过程,并获取了为期20天的模式数据。分析结果表明,自吕宋海峡产生的内孤立波在传播过程中逐渐由下凹型转变为上凸型。具体而言,下凹型内孤立波的上层流速向西北方向流动,下层流速向东南方向流动,而上凸型内孤立波的流速方向则完全相反。在传播路径上,形成了第二模态内孤立波,其上层等温线向上凸起,下层等温线向下凹陷,同时垂向上流速呈现上下层流速方向相反的情况。

Internal solitary waves,as an important dynamic process in the South China Sea,have a significant impact on the transport of water and substances,and have an impact on the ecological environment of the South China Sea.During the propagation process,internal solitary waves undergo morphological changes,leading to different ecological effects.The article simulates the propagation process of solitary waves in the northern South China Sea based on the MITgcm numerical model and obtains 20 days of model data.The analysis results indicate that the internal solitary waves generated from the Luzon Strait gradually transform from concave to convex during propagation.Specifically,the upper flow velocity of concave internal solitary waves flows in the northwest direction,while the lower flow velocity flows in the southeast direction,and the flow velocity direction of convex internal solitary waves is completely opposite.On the propagation path,the second mode internal solitary wave is also formed,with the upper isotherm protruding upward and the lower isotherm sagging downward,and the vertical upward flow velocity shows the opposite direction of the upper and lower flow velocities.