Modeling the Trade-Wind Cumulus Boundary Layer. Part I: Testing the Ensemble Cloud Relations Against Numerical Data

Abstract

The possibility of studying the cloudy planetary boundary layer through one-dimensional modeling is investigated. The various possible parameterizations of mean liquid water content and correlations, in term of the known statistical properties of the conservative variables θ₁, and q_w are examined in comparison with the results of a three-dimensional numerical model. The “Gaussian” cloud model is removed and a simple, skew exponential distribution is found to be most efficient for parameterizing the turbulent kinetic energy buoyancy production by latent beat release, in the case of the trade-wind cumulus layer. This distribution fits well the histograms of conservative thermodynamic variables and vertical velocity, computed from the three-dimensional data.