Large-eddy simulation of a cold pool and its moisture ring: Shown are isosurfaces of the water-vapor mass density perturbation (at (red) 0.4 g m-3 and (blue) -1.0 g m-3).
Deep convection over ocean has commonly been found to be initiated from rings of enhanced moisture content near the edges of evporatively-driven cold pools. In this study, we explore the origin of these water-vapor rings using large-eddy simulations. In contrast to the prevailing explanation based on rain drop evaporation, we demonstrate a dominating role from surface latent-heat fluxes. The newly proposed mechanism has far-reaching implications for parameterizations in GCMs. Currently, such parameterizations do not take into account the potential for deep convection that arises from these water-vapor rings.