Stability Properties of Large-scale Baroclinic Disturbances in a Vertically and Horizontally Variable Zonal Current

[摘要] The changes of energies of the mean flow with the vertical and horizontal shears and a superimposed disturbance are discussed, using the quasigeostrophic vorticity equation.Stability properties of the simple baroclinic atmosphere which is made up from the northern hemispheric data after Starr and White (1954) are investigated by means of the so-called “energy method ”. The direction of the energy flow is examined for various ranges of the disturbance wave length. It is found that amounts of increase of the kinetic energy of the mean flow due to non-linear interaction seem to be sufficient to overcome those which are continuously exhausted within the friction layer near the ground.The unstable baroclinic disturbance tends to produce the poleward and upward transport of sensible heat, and simultaneously the intensity of the zonal current is strengthened by concentration of eddy zonal momentum due to the presence of the latitudinal variation of the mean flow.

[学科分类] 大气科学