Planetary wave modelling of the Middle Atmosphere: the importance of travelling wave components

Abstract

A linearized stationary planetary wave model is applied to mean data for a chosen quiescent winter month (December 1979). Comparison with observations from the Stratospheric Sounding Unit on board NOAA-6 shows that both the amplitude and height of propagation of wavenumber one are significantly underpredicted. This behaviour is not substantially modified by extension to more sophisticated model formulation and representation of dissipative processes. It is shown that the response to forcing varies appreciably with travelling wave frequency, even at periods greater than one month and it is suggested that this sensitivity is a significant limitation on the applicability of stationary wave models based only on time mean behaviour. 763