地转气流中的重力惯性内波

本文用一个一维线性的二层模式,分析了地转气流中重力惯性内波的动力学性质。讨论了重力惯性内波的不稳定性、相速度和群速度后,指出: 1)当地转风速大于重力内波波速时,某些尺度的重力惯性内波可以产生不稳定性,这种不稳定性可以用来解释某些中系统的发展。 2)某些波长的重力惯性内波,它的群速度可以大于相速度;因此在某一地区有中系统发展时,它的能量可以很快地传到下游,而在某下游产生新的系统。

SOME ASPECTS ON THE GRAVITATIONAL WAVES IN A GEOSTROPHIC CURRENTS

In this paper,the instability,phase velocity and group velocity of the gravitational waves in a geostrophic currents arc analysed by using a two layer model.The conclusions reached arc that:1.When the Froude number is greater than unit,the gravitational waves of some wave lengths will become unstable.This instability may be used to explain the development of some meso-scale systems.2.The group velocity of the gravitational waves can exceed its phase velocity.Therefore,when a meso-scale system is developed in some regions,its energy can travel faster downwind than the phase velocity,therefore a new wave may be formed in the front of the old one.