P1.71
Tropical convection and large-scale equatorial disturbances: Results from 2D cloud-resolving and 3D CRCP global modeling (Formerly paper 3C.2)
Wojciech W. Grabowski, NCAR, Boulder, CO; and P. K. Smolarkiewicz and M. Andrejczuk
This presentation will discuss numerical results pertinent to the problem of large-scale convection organization in the tropics. The problem spans a wide range of spatial and temporal scales and involves several physical processes, such as atmosphere-ocean interaction, moist convection, cloud microphysics, radiative transfer, and equatorial wave dynamics. Many theories have been proposed in the past to explain the observed large-scale convection organization (e.g., wave-CISK, WISHE, water vapor feedback, stochastic convective excitation, etc.). First, 2D (x-z) cloud-resolving simulations will be presented in which a periodic global-scale horizontal domain is used (20,000 km) and a horizontally homogeneous SST is assumed. These idealized simulations are relevant to understanding the interaction between tropical convection and eastward-propagating Kelvin waves. Indeed, the spontaneous organization of convection into eastward-propagating super-cloud-clusters is observed in some of the 2D simulations. Second, the interaction between equatorially-trapped disturbances and tropical convection as simulated by a nonhydrostatic global model applying the cloud-resolving convection parameterization (CRCP, Grabowski and Smolarkiewicz, 1999, Physica D) will be discussed. The CRCP technique represents subgrid scales of the global model by imbedding a 2D cloud-resolving model in each column of the global model. Such an approach is tailored for distributed memory architectures. The modeling setup is a constant SST aquaplanet (with the size and rotation as Earth) in radiative-convective equilibrium. Spontaneous development of eastward-propagating equatorially-trapped disturbances coupled with tropical super-cloud-clusters is observed in these simulations. The presentation will discuss these results in the context the current theories explaining the coupling between convection and large-scale dynamics in the tropics.
Poster Session 1, Lunch Poster Session (Lunch provided at Convention Center with sponsorship from Aerosonde Robotic Aircraft Pty Ltd, Hawthorn, Vic., Australia)
Wednesday, 24 May 2000, 12:00 PM-1:45 PM
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