Can an E–l Turbulence Closure Simulate Entrainment in Radiatively Driven Convective Boundary Layers?

Abstract

The simulation of entrainment by an (E?l) turbulent kinetic energy?diagnostic length scale closure model is investigated in a smoke cloud convective boundary layer. The behavior of the E?l scheme is compared with two simple entrainment closures based on the integral turbulent kinetic energy budget of the boundary layer: one based on Eulerian partitioning and the other based on process partitioning of the buoyancy flux. It is demonstrated that the E?l turbulence scheme strongly supports the entrainment closure based on Eulerian partitioning. However, results of large eddy simulation (LES) models point in the other direction and support process partitioning. This suggests that the representation of entrainment physics in the E?l model is essentially different from that in LES models.