低纬地区超长波的三维分析

THREE DIMENSIONAL ANALYSIS OF ULTRA-LONG WAVES IN LOW LATITUDES

摘要:

本文从原始方程组出发,在赤道β平面上采用正交模态法,对低纬超长波进行水平结构和垂直结构分析,发现低纬超长波主要出现在对流层上层和平流层低层。其次,本文还讨论了含有低纬理想热源的原始方程模式,并通过对模式求数值解得出:低纬热源强迫是对流层上层Kelvin波的形成原因之一。

Abstract:

The purpose of this study is to gain a better understanding of the distribution of ultra-long waves in low latitudes. The behavior of the ultra-long waves, wavenumber 1-3, is investigated in terms of vertical and horizontal Normal modes decompositions.In this paper, the primitive equations on the β-plane in low latitudes are described. A latitudinal mean flow containing the easterly shear is considered as a basic state. Firstly primitive equations are linearized, then decomposed. Horizontal structure equations are resolved by Normal modes. The results show that the ultra-long waves exist in the upper troposphere and lower stratosphere. Rossby wave is the main element which affects flow field in low latitudes.Secondly, the primitive equations with idealized heat sources in low latitudes are discussed, and solved numerically. The results show that the forcing of the heat sources in low latitudes is one of the factors forming ultra-long waves in the upper troposphere and lower stratosphere.