Abstract

The large scale dynamics of the atmosphere can be described by mathematically well-posed asymptotic limit equations. The semi-geotriptic equations are used in diagnostic mode for this purpose. This system includes the effect of large variations in the basic state and its anisotropic structure, which are both essential for predicting the occurrence of atmospheric turbulence. It also includes the atmospheric boundary layer, where most turbulence occurs. In the talk it will be shown that the system does indeed replicate the large-scale behaviour of the Met Office operational model. The effect of moisture on the large-scale flow is demonstrated. A major use of this method is to track down systematic errors. It is shown how errors in the large-scale subtropical circulation can be explained by errors in the distribution of moist convection.