Interaction of the Convective Energy Cycle and Large-Scale Dynamics

Abstract The importance of the convective life cycle in tropical large-scale dynamics has long been emphasized, but without explicit analysis. The present work provides it by coupling the convective energy cycle under the framework of Arakawa and Schubert’s (1974) convection parameterization with a shallow-water analogue atmosphere. A careful derivation of the system is first presented, because it is rather missing in the literature. The squared frequency of linear convectively-coupled waves is given by a squared sum of the dry gravity-wave and the convective energy-cycle frequencies, shortening the period of the convective cycle through the large-scale coupling. In a weakly nonlinear regime, the system follows an equation analogous to the Kortweg-de Vries equation, which exhibits a solitary-wave solution, with behavior reminiscent of observed tropical westerly-wind bursts.