Dyuamical Effects of the Variable Tropopause

[摘要] A computational model for large scale motions which extends to the stratosphere is designed. The model has the tropopause and ground surface, and is favorable in treating the interaction between the tropospheric and stratospheric motions. A special σ-coordinate in the vertical is used, and the tropopause is assumed to be a material surface at which dσ/dt vanishes.Fundamental equations of the model are illustrated, and energetical considerations are given. Particular interest is put in the interaction of kinetic energy between the troposphere and the stratosphere in the short term evolution of the atmospheric motion. Calculation based on the actual data is made for the vertical transfer of kinetic energy through the tropopause.Analytical solutions of perturbations superimposed on the basic tonal current are obtained for barotropic and baroclinic models and compared with those of p-coordinate system. The kinetic energy transport in vertical as well as control of the false westward retrogression of the ultra-long wave, due to the non-vanishing vertical mean divergence in the troposphere, are shown. Modification of the criterion of baroclinic instability due to the existence of the stratosphere is discussed.

[学科分类] 大气科学