Large-scale and climate models rely on subgrid-scale modeling to represent (or ``parameterize'') moist convection. Consequently, key aspects of clouds in the problem of tropical dynamics, such as the interaction of convection with radiative or surface processes, cannot be directly investigated. A cloud-resolving modeling approach, on the other hand, considers the convective response to the prescribed large-scale conditions, but it allows for no feedback from cloud-scale dynamics into the large-scale flow. One of the conclusions drawn from our cloud-resolving studies of GATE and TOGA COARE cloud systems is that a two-dimensional (2D) framework does offer a meaningful representation of the tropical convection, including interaction of clouds with radiation and effects of convection on surface heat fluxes (Grabowski et al. JAS 1998; Wu et al. JAS 1998). This result leads us to believe that it is possible to develop a three-dimensional (3D) large-scale model (with horizontal resolution of the order of 100 km) in which convective processes are represented in each model column by a 2D cloud resolving model. We refer to this approach as a ``cloud resolving convection parameterization''. This approach is ideal for parallel computations and currently seems the only way to include elements of cloud dynamics into 3D large-scale and climate models. This approach has been successfully tested by comparing 2D cloud-resolving simulations of the Walker-like circulation (Grabowski JAS 1998) and 3D cloud-resolving simulations of the GATE cloud systems (Grabowski et al. JAS 1998) with simulations applying the CRCP approach. The CRCP approach is now being applied to the problem of equatorial beta-plane dynamics. Details of the approach and results of the equatorial beta-plane simulations will be presented at the meeting.
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12th Conference on Atmospheric and Oceanic Fluid Dynamics