内波频散关系的一种数值解法

A NUMERICAL METHOD OF INTERNAL WAVES DISPERSION RELATION

基于Ｆｌｉｇｅｌ等（１９７５）采用的Ｔｈｏｍｐｓｏｎ－Ｈａｓｋｅｌｌ算法（Ｈａｓｋｅｌｌ，１９５１），在取消Ｂｏｕｓｓｉｎｅｓｑ近似的条件下求解线性内波方程，以研究内波的频散关系及其各种模态的垂直速度振幅随深度分布的特征。本文以南海（１３°３０′Ｎ，１１８°３０′Ｅ）、（９°３０′Ｎ，１１１°３０′Ｅ）两个测站夏季和冬季的内波特征的计算为例，分别用Ｆｌｉｇｅｌ等原先的方法（引入Ｂｏｕｓｓｉｎｅｓｑ近似）和本文改进的方法（取消Ｂｏｕｓｓｉｎｅｓｑ近似）进行了计算；结果表明：对于垂直波数较小的内波，在取消Ｂｏｕｓｓｉｎｅｓｑ近似情况下，其计算精度可获得明显的提高。

Based on the Thompson-Haskell's calculation method (Haskell, 1951)used by Fligel et al.(1975),we solved linear internal wave equation without the condition of Boussinesq approximation to study the dispersion of internal wave and the characteristics of vertical velocity amplitude versus depth of some modes. As examples, the characteristics of internal wave in summer and winter of two observation stations, i'. e.,(13°30′N, 118°30′E) and (9°30′N, 111°30′E) in the South China Sea are calculated using the method used by Fligel et al. (with Boussinesq approximation) and the improved method(without Boussinesq approximation) respectively in this paper; the results show,that: For the lower wave number internal wave, the calculation precision is obviously improved without the condition of Boussinesq approximation.