The Beta Drift of Baroclinic Vortices. Part II: Diabatic Vortices

Abstract

Abstract The beta drift of diabatic vortices is investigated with a three-dimensional primitive equation model with simple physical parameterizations. The vertical coupling mechanism discussed in Part I is extended to include the effects of diabatic heating and moist processes. The results show that the motion and evolution of the diabatic vortices can substantially differ from those of adiabatic vortices. The anticyclone at the upper troposphere tends to propagate equatorward and westward due to the Rossby wave dispersion. But the continuous regeneration of an anticyclonic PV anomaly by diabatic heating keeps the upper-level anticyclone in a band stretching from the vortex core to several hundred kilometers equatorward and westward. Downward penetration of the circulation associated with these anticyclonic PV anomalies reduces the westward motion of the diabatic vortices by the vertical coupling mechanism discussed in Part I. This also rotates the lower-level beta-gyres anticyclonically, resulting in a m...