Effects of the baroclinic adjustment on the tropopause in the NCEP-NCAR reanalysis

Abstract

In this work, we study the mean tropopause structure from the NCEP-NCAR reanalysis in the framework of a theory of baroclinic adjustment, focusing on the impact of baroclinic eddies on the mean tropopause height. In order to measure the effects of such perturbations, we introduce an appropriate global index that selects events of high baroclinic activity and allows us to individuate the phases of growth and decay of baroclinic waves. We then composite the tropopause mean structure before and after a baroclinic event, finding that baroclinic disturbances cause the zonally averaged midlatitude winter tropopause height to rise. Our results suggest that the baroclinic adjustment processes should be taken into account to explain the nature of the midlatitude tropopause.