Coupling between convection and large-scale circulation

Friday, 19 December 2014
Tobias Becker, Bjorn B Stevens and Cathy Hohenegger, Max Planck Institute for Meteorology, Hamburg, Germany
The ultimate drivers of convection - radiation, tropospheric humidity and surface fluxes – are altered both by the large-scale circulation and by convection itself. A quantity to which all drivers of convection contribute is moist static energy, or gross moist stability, respectively. Therefore, a variance analysis of the moist static energy budget in radiative-convective equilibrium helps understanding the interaction of precipitating convection and the large-scale environment. In addition, this method provides insights concerning the impact of convective aggregation on this coupling. As a starting point, the interaction is analyzed with a general circulation model, but a model intercomparison study using a hierarchy of models is planned. Effective coupling parameters will be derived from cloud resolving models and these will in turn be related to assumptions used to parameterize convection in large-scale models.