Direct Calculation of Low-Frequency Coastally Trapped Waves and Their Scattering
Direct Calculation of Low-Frequency Coastally Trapped Waves and Their Scattering
复制标题
低频沿海陷波及其散射的直接计算
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
E. Johnson
中科院分区：
文献类型：
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作者：
G. Schmidt;E. Johnson
提出了一种新的直接数值方法，用于查找连续分层流中低频非色散沿海困波的相速度和压力场。通常的二维问题被简化为跨架的一维积分方程。问题的结构取决于典型浮力频率 N0、深度 D、科里奥利参数 f 和架宽 L 的参数 B = N0D/fL 测量的分层强度。对于强分层（B 远大于 1）和弱分层（B 远小于 1）都给出了渐近近似，并尝试使用 Pade 近似提供整个 B 范围内的相速度的解析表达式。这些与数值结果很好地比较。给出了使用许多不同地形的示例，并讨论了斜压波模式和正压波模式之间发生模式接触的条件。该方法特别适合评估从一种地形移动到另一种地形的波的散射。
A new, direct numerical method is proposed for finding the phase speeds and pressure fields of low-frequency nondispersive coastally trapped waves in a continuously stratified flow. The usual two-dimensional problem is reduced to a one-dimensional integral equation across the shelf. The structure of the problem depends on the strength of the stratification measured by the parameter B = N0D/fL for typical buoyancy frequency N0, depth D, Coriolis parameter f, and shelf width L. Asymptotic approximations are given for both strong (B much greater than 1) and weak (B much less than 1) stratification, and attempts are made to provide analytical expressions for the phase speeds over the whole range of B using Pade approximations. These compare well with the numerical results. Examples are given using a number of different topographies and the conditions for which mode kissing between baroclinic and barotropic wave modes occur are discussed. The method is particularly suited to evaluating the scattering for waves moving from one topography to another.