Journal of Geophysical Research, 115, D12110, doi:10.1029/2009JD013376.

Multiple equilibria in a cloud-resolving model

Sharon L. Sessions, Satomi Sugaya, David J. Raymond
Department of Physics, New Mexico Institute of Mining and Technology, Socorro, NM.

Adam H. Sobel
Department of Applied Physics and Applied Mathematics and Department of Earth and Environmental Sciences, Columbia University, New York, NY.


Multiple equilibria corresponding to either a state with persistent, precipitating deep convection or a non-precipitating state are shown to exist in a cloud resolving model employing the weak temperature gradient (WTG) approximation. WTG is important for the existence of both equilibria; numerical experiments show that a weak enforcement of WTG eliminates the dry non-precipitating state. In situations which support both equilibria, we find that the dry equilibrium has a small or negative gross moist stability, while larger values correspond to the precipitating equilibrium.