Relative importance of tropopause structure and diabatic heating for baroclinic instability

Abstract. Misrepresentations of wind shear and stratification around the tropopause in numerical weather prediction models can lead to errors potential vorticity gradients with repercussions for Rossby wave propagation baroclinic instability. Using a diabatic extension linear quasi-geostrophic Eady model featuring tropopause, we investigate influence such discrepancies on instability by varying sharpness altitude as well lower stratosphere, which be associated or data assimilation downward weakened polar vortex. We find that development is less sensitive than modifications where latter are net change vertical integral horizontal gradient across tropopause. To further quantify relevance these sensitivities, compare findings impact including mid-tropospheric latent heating. For representative shear, stratification, heating intensity, sensitivity structure significantly different intensities. These indicate might important previously anticipated stratosphere could play more crucial role, being dominant factor.