Basic entrainment equations for the atmospheric boundary layer

The parameterization of penetrative convection and other cases of turbulent entrainment by the atmospheric boundary layer is reviewed in this paper. The conservation equations for a one-layer model of entrainment are straightforward; all modeling problems arise in the context of the parameterization of various terms in the budget of turbulent kinetic energy. There is no consensus in the literature on the parameterization of shear production and of dissipation. Unfortunately, field experiments are not sufficiently accurate to guide the selection of suitable hypotheses. Carefully designed laboratory experiments are needed to settle the problems that remain.This paper has also been presented as Invited Paper at the Second IAHR Symposium on Stratified Flows, Trondheim, Norway, June 24–27, 1980.Free University, Amsterdam, The Netherlands.