Diffusive Decay of Tropopause Folds and the Related Cross-Tropopause Mass Flux

Abstract

The role of vertical mixing processes in destroying tropopause folds is studied with the help of a two-dimensional isentropic model. Two vertical diffusion parameterizations are tested. The first parameterization was developed by Gidel and Shapiro with eddy diffusivity derived from aircraft measurements, while the second is the one that is incorporated in the mesoscale model MM4. The second approach is more effective in dissolving the tropopause fold. The resulting cross-tropopause mass flux sensitivily depends both on the chosen parameterization and the definition of the tropopause.