Group seminar on 12. April, 14:15 CET

An intermediate complexity model of moist tropical dynamics

Katharina M. Holube

Tropical dynamics are characterized by the smallness and sign change of the Coriolis parameter at the equator, the consequence being some atmospheric phenomena different from those typical for the mid-latitudes. Since the horizontal circulations in the lower and upper tropical troposphere are on average of opposite signs, it is possible to model basic features of the tropical circulation with a single-layer numerical model. In my talk, I will describe such a model developed by A. Gill (1982) which includes effects of moisture. A positive feedback between moisture and latent heat release produces hurricane-like structures. I will explain differences between the dynamics in standard rotating shallow-water model and the Gill's model by showing simulations with the Moist Atmosphere Dynamics (MAD) model which solves Gill's model equations numerically. The focus is on interactions between circulation and moisture. Furthermore, I will discuss applications of this single-layer model in understanding other aspects of the tropical circulation.