Abstract. In this paper, a regional study of the mode-2 internal solitary waves (ISWs) in the Pacific coast of Central America is carried out by using seismic reflection method. The observed relationship between the dimensionless phase velocity and the dimensionless amplitude (DA) of the mode-2 ISWs was analysed. When DA < 1, the dimensionless phase velocity increases with the increasing dimensionless amplitude, divided into two parts with different growth rates. When DA > 1, the dimensionless phase velocity increases with the increasing dimensionless amplitude at a relatively small growth rate. We suggest that the influences of seawater depth (submarine topography), pycnocline depth, and pycnocline thickness on the phase velocity of the mode-2 ISWs in the study area, cause the relationship between the dimensionless phase velocity and the dimensionless amplitude diversified. The observed relationship between the dimensionless wavelength and the dimensionless amplitude of the mode-2 ISWs was also analysed. When DA < 1 and DA > 2, the dimensionless wavelength decreases and increases with the increasing dimensionless amplitude, respectively. Additionally, the seawater depth has a great influence on the wavelength of the mode-2 ISWs in the study area, and overall the wavelength increases with the increasing seawater depth. As for the vertical structure of the amplitude of the mode-2 ISWs in the study area, we find that it is affected by the nonlinearity of the ISWs and the pycnocline deviation (especially the downward pycnocline deviation).

中文翻译：

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利用海洋地震勘测资料对中美洲太平洋沿岸模式 2 内部孤立波进行区域研究

摘要。本文利用地震反射法对中美洲太平洋沿岸的模式2内部孤立波(ISWs)进行了区域研究。分析了观察到的无量纲相速度与模式 2 ISW 的无量纲振幅 (DA) 之间的关系。当 DA < 1 时，无量纲相速度随着无量纲振幅的增加而增加，分为两部分，增长率不同。当 DA > 1 时，无量纲相速度随着无量纲振幅的增加而增加，增长率相对较小。我们认为海水深度（海底地形）、密跃层深度和密密层厚度对研究区模式 2 ISW 相速度的影响，导致无量纲相速度与无量纲振幅之间的关系多样化。还分析了观察到的无量纲波长和模式 2 ISW 的无量纲幅度之间的关系。当 DA < 1 和 DA > 2 时，无量纲波长分别随着无量纲振幅的增加而减少和增加。此外，海水深度对研究区模式2 ISWs的波长影响很大，总体上随着海水深度的增加波长增加。对于研究区2模态ISWs振幅的垂直结构，我们发现它受ISWs非线性和pycnocline偏差（特别是向下pycnocline偏差）的影响。还分析了观察到的无量纲波长和模式 2 ISW 的无量纲幅度之间的关系。当 DA < 1 和 DA > 2 时，无量纲波长分别随着无量纲幅度的增加而减少和增加。此外，海水深度对研究区模式2 ISWs的波长影响很大，总体上随着海水深度的增加波长增加。对于研究区2模态ISWs振幅的垂直结构，我们发现它受ISWs非线性和pycnocline偏差（特别是向下pycnocline偏差）的影响。还分析了观察到的无量纲波长和模式 2 ISW 的无量纲幅度之间的关系。当 DA < 1 和 DA > 2 时，无量纲波长分别随着无量纲振幅的增加而减少和增加。此外，海水深度对研究区模式2 ISWs的波长影响很大，总体上随着海水深度的增加波长增加。对于研究区2模态ISWs振幅的垂直结构，我们发现它受ISWs非线性和pycnocline偏差（特别是向下pycnocline偏差）的影响。无量纲波长分别随着无量纲振幅的增加而减少和增加。此外，海水深度对研究区模式2 ISWs的波长影响很大，总体上随着海水深度的增加波长增加。对于研究区2模态ISWs振幅的垂直结构，我们发现它受ISWs非线性和pycnocline偏差（特别是向下pycnocline偏差）的影响。无量纲波长分别随着无量纲振幅的增加而减少和增加。此外，海水深度对研究区模式2 ISWs的波长影响很大，总体上随着海水深度的增加波长增加。对于研究区2模态ISWs振幅的垂直结构，我们发现它受ISWs非线性和pycnocline偏差（特别是向下pycnocline偏差）的影响。