Abstract
In Section 2 the linearized form of equations, in which we used pressure as the vertical coordinate, has been analyzed as an initial value problem for the five cases of the 2-, 6-, 10-, 14- and 20-level models. It is found in the 20- level model that (1) the vertical velocity in the stratosphere has an opposite sign with that in the troposphere, (2) the sensible heat flux due to disturbance is northward not only in the lower troposphere but also in the stratosphere, separated by the southward flux in the intermediate zone. By means of the less detailed model, where the number of the information levels is less than ten, the characteristic features in the stratosphere mentioned above can not be well demonstrated. It has also been analyzed the second derivative of the kinetic energy with respect to time to examine how the instability of the disturbance differs with the different numbers of the information levels.
In Section 3 we have first introduced the new vertical coordinate s= (ρ/ρ0)1/2, and then performed the same kind of analysis as we did in Section 2. The use of the s-coordinate has an advantage in a sense that the characteristic features in the stratosphere mentioned before can easily be reproduced by the 4-level model.
