Estimation of entrainment rate in simple models of convective clouds

Abstract

A method for estimating lateral entrainment rate in clouds is suggested, linking its magnitude to buoyant production of vertical kinetic energy within a cloud updraught. In single-column model studies the formulation captures the high values of entrainment seen in shallow convection and the values an order of magnitude lower in cases of deep convection, as suggested by observational studies and large-eddy model simulations, together with a realistic vertical variation. Comparison is made with other recent attempts to parametrize entrainment.