P1F.10 A simple multicloud parametrization for convectively coupled waves with an active boundary layer

Tuesday, 29 April 2008
Palms ABCD (Wyndham Orlando Resort)
Michael L. Waite, University of Victoria, Victoria, BC, Canada; and B. Khouider

Intermediate models with crude vertical resolution are an important tool in the study of tropical convection and convectively coupled waves. They are comprehensive enough to represent many features of tropical convection, yet simple enough to permit detailed mathematical analysis. As such, they provide a powerful framework for assessing various convective parameterization concepts. Intermediate models often employ a simple passive boundary layer, in which the bulk equivalent potential temperature evolves due to surface evaporation and environmental and convective downdrafts. In this poster, we will present equations for boundary layer velocity, temperature and moisture that include the effects of divergence and turbulent mixing with the free atmosphere. This enhancement generalizes the applicability of simple models to problems such as the diurnal cycle, land-sea contrasts, and cloud-radiative feedback. The system is developed in the context of the Khouider-Majda multicloud model [Khouider & Majda 2006, J. Atmos. Sci. 63, 1308-1323], using ideas from Stevens [2006, Theor. Comput. Fluid Dyn. 20, 279-304]. We will present a linear stability analysis and nonlinear simulations of convectively coupled waves, and discuss the effects of coupling with an active boundary layer.
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