A Unified Model for Moist Convective Boundary Layers Based on a Stochastic Eddy-Diffusivity/Mass-Flux Parameterization

• DOI: 10.1175/jas-d-12-0106.1
• Publication Date: 2013-02-01T18:30:12Z
• Authors: Kay Sušelj; João Teixeira; Daniel Chung
• Keywords: Mass flux; Entrainment (biomusicology); Eddy diffusion; Large-Eddy Simulation; Convective Boundary Layer

Abstract A single-column model (SCM) is developed for representing moist convective boundary layers. The key component of the SCM parameterization subgrid-scale vertical mixing, which based on a stochastic eddy-diffusivity/mass-flux (EDMF) approach. In EDMF framework, turbulent fluxes are calculated as sum kinetic energy–based eddy-diffusivity and mass-flux component. mass flux modeled fixed number steady-state plumes. main challenge to properly represent cumulus clouds, solutions have account realistic representation condensation within plumes lateral entrainment into At level mean updraft, joint pdf conserved variables velocity used estimate proportion dry sampled in Monte Carlo way creating predefined rate process resulting decrease cloudiness with height above cloud base. addition scheme, following processes included SCM: pdf-based condensation, simple longwave radiation, one-dimensional dynamics. Note that this approach there two distinct pdfs, one variability updraft properties other thermodynamic surrounding environment. authors show able capture essential features layers, ranging from stratocumulus shallow-cumulus regimes. Detailed comparisons, include profiles, integrated budgets Barbados Oceanographic Meteorological Experiment (BOMEX), Dynamics Chemistry Marine Stratocumulus (DYCOMS), large-eddy simulation (LES) cases, discussed confirm quality present