Zonally Symmetric Model for the Summer Monsoon Circulation

Abstract:

We develop a zonally symmetric atmospheric model for the large-scale flow which incorporates both the small-scale effect of deep tropospheric convection and a dynamical boundary layer that sustains shallow convection. The model allows to study the propagation and initiation of convection and its interaction with the large-scale circulation without the effects of zonally propagating atmospheric waves. The free tropospheric nonlinear wave dynamics is described using the barotropic and first two baroclinic modes, and the stochastic multicloud model of Khouider et al. (2010) is used to represent the unresolved features of organized tropical convection. Results from nonlinear stochastic simulations are presented and demonstrate that the model reproduce well the mean local Hadley cell structure and some monsoon-like features such as the signature of the monsoon trough and convective mesoscale variability.