Development of Boundary Layer Parameterization for Simulating Moist Convective Boundary Layers

Moist convective boundary layers are ubiquitous in the Earth's atmosphere. Boundary layer clouds substantially influence the planetary albedo and control the Earth's climate, but despite their importance, are often not well represented in climate and weather models impairing our forecast and climate prediction capabilities. The aim of this study is to develop a boundary layer parameterization capable of simulating stratocumulus (Sc) and cumulus (Cu) convection, and the transition from Sc to Cu. The proposed boundary layer scheme consists of a combined eddy-diffusivity and mass-flux parameterization for turbulent fluxes and a pdf-based cloud/condensation scheme. The mass-flux description is based on a novel approach consisting of multiple dry and moist convective updrafts. The parameterization is implemented in a one-dimensional model. The results for some typical moist convective case studies are presented where the one-dimensional model is evaluated against large-eddy simulations.