This project takes a unique approach to develop a new method for representing cumulus convection in large-scale weather and climate models (i.e., any models with spatial resolution low enough that they do not resolve cloud processes directly). The project will exploit insights into how convection interacts with its environment -- buoyancy anomalies produced by convective heating are quickly removed by wave action, a process which produces a mean vertical velocity that creates adiabatic cooling just sufficient to counterbalance the heating. As one of its main effects, this "weak temperature gradient vertical velocity" advects moisture. This realization motivates the development of a "test cell" in which explicit cumulus ensemble models and parametric treatments of convection will be tested. The investigators will use these results to modify and tune an existing prototype cumulus parameterization. This parameterization would then be used in a large-scale model to evaluate its effects on simulated features of the general circulation of the atmosphere such as tropical easterly waves and intraseasonal oscillations. The diurnal cycle will also be examined in a simplified context. The project will support research by undergraduate students as well as graduate students.
