Moist Convective Velocity and Buoyancy Scales

Abstract

Velocity, buoyancy, and fractional area scales for moist convection in statistical equilibrium with large-scale forcing are derived using the constraints of global energy and entropy conservation, and subcloud-layer thermodynamic equilibrium. The magnitudes of the velocity and buoyancy in moist convective clouds are shown to depend on cloud microphysical properties and on the vertical distribution, but not the magnitude, of the large-scale forcing. Comparisons of the theoretically derived scales with velocity and buoyancy values observed in a numerical ensemble cloud model and in a one-column radiative-convective model show good agreement.