A New Boundary Layer Mixing Scheme. Part I: Scheme Description and Single-Column Model Tests

A new boundary layer turbulent mixing scheme has been developed for use in the UKMO weather forecasting and climate prediction models. This includes a representation of nonlocal mixing (driven by both surface fluxes and cloud-top processes) in unstable layers, either coupled to or decoupled from the surface, and an explicit entrainment parameterization. The scheme is formulated in moist conserved variables so that it can treat both dry and cloudy layers. Details of the scheme and examples of its performance in single-column model tests are presented.

[1]  Adrian Lock,et al.  A New Boundary Layer Mixing Scheme. Part II: Tests in Climate and Mesoscale Models , 2000 .

[2]  C. Bretherton,et al.  A GCSS Boundary-Layer Cloud Model Intercomparison Study Of The First Astex Lagrangian Experiment , 1999 .

[3]  B. Stevens,et al.  Including Radiative Effects in an Entrainment Rate Formula for Buoyancy-Driven PBLs , 1999 .

[4]  A. Brown.  The sensitivity of large‐eddy simulations of shallow cumulus convection to resolution and subgrid model , 1999 .

[5]  A. Lock.  The parametrization of entrainment in cloudy boundary layers , 1998 .

[6]  A first order mixing-condensation scheme for nocturnal stratocumulus , 1998 .

[7]  Albert A. M. Holtslag,et al.  Impact of Skewness and Nonlocal Effects on Scalar and Buoyancy Fluxes in Convective Boundary Layers , 1998 .

[8]  P. Duynkerke,et al.  Observed Lagrangian transition of stratocumulus into cumulus during ASTEX : Mean state and turbulence structure , 1997 .

[9]  A. Holtslag,et al.  Evaluation and model impacts of alternative boundary-layer height formulations , 1996 .

[10]  A. Brown.  Evaluation of parametrization schemes for the convective boundary layer using large-eddy simulation results , 1996 .

[11]  A. Slingo,et al.  Studies with a flexible new radiation code. I: Choosing a configuration for a large-scale model , 1996 .

[12]  James C. McWilliams,et al.  An evaluation of neutral and convective planetary boundary-layer parameterizations relative to large eddy simulations , 1996 .

[13]  P. Minnis,et al.  Observations of the Interaction between Cumulus Clouds and Warm Stratocumulus Clouds in the Marine Boundary Layer during ASTEX. , 1995 .

[14]  A. P. Siebesma,et al.  Evaluation of Parametric Assumptions for Shallow Cumulus Convection , 1995 .

[15]  Albert A. M. Holtslag,et al.  Local Versus Nonlocal Boundary-Layer Diffusion in a Global Climate Model , 1993 .

[16]  John F. B. Mitchell,et al.  Carbon Dioxide and Climate. The Impact of Cloud Parameterization , 1993 .

[17]  P. Hignett.  Observations of Diurnal Variation in a Cloud-capped Marine Boundary Layer , 1991 .

[18]  P. Rowntree,et al.  A Mass Flux Convection Scheme with Representation of Cloud Ensemble Characteristics and Stability-Dependent Closure , 1990 .

[19]  C. Bretherton,et al.  Buoyancy reversal and cloud‐top entrainment instability , 1990 .

[20]  R. Smith.  A scheme for predicting layer clouds and their water content in a general circulation model , 1990 .

[21]  Stephen Nicholls,et al.  Observations of marine stratocumulus clouds during FIRE , 1988 .

[22]  I. Troen,et al.  A simple model of the atmospheric boundary layer; sensitivity to surface evaporation , 1986 .

[23]  A. G. Driedonks,et al.  Models and observations of the growth of the atmospheric boundary layer , 1982 .

[24]  J. Businger,et al.  A Model for Entrainment into a Cloud-Topped Marine Boundary Layer. Part I: Model Description and Application to a Cold-Air Outbreak Episode , 1981 .

[25]  J. Louis.  A parametric model of vertical eddy fluxes in the atmosphere , 1979 .

[26]  L. Mahrt.  Mixed Layer Moisture structure , 1976 .

[27]  S. Zilitinkevich.  Comments on “A Model for the Dynamics of the Inversion Above a Convective Boundary Layer” , 1975 .