Abstract We describe the results of January and July simulations carded out with a nine-level spectral model, employing a rhomboidal truncation at wavenumber 15. Sea-surface temperature, sea-ice distribution and solar zenith angle are held constant in each simulation. The model includes interactive clouds and radiative processes after Ramanathan et al. (1983). Selected fields are shown which highlight the model's strengths and weaknesses. The latitude-height distribution of the zonal wind is successfully simulated. The model captures the separation between the wintertime westerly jets in the troposphere and stratosphere and thus simulates the sign reversal in the vertical wind shear across the jet axis in the upper troposphere. In addition to the zonal wind, we show also the zonally averaged temperature, meridional wind and vertical velocity. Regional distributions of sea-level pressure, surface air temperature, precipitation and a number of other fields defined at various pressure levels are compared in ...