Parameterization of moist convection in the National Center for Atmospheric Research community climate model (CCM2)

The National Center for Atmospheric Research (NCAR) community climate model (CCM) has historically made use of a moist adiabatic adjustment procedure for parameterizing the effects of moist convection. The most recent version of the NCAR CCM, CCM2, has abandoned this approach in favor of a stability-dependent mass-flux representation of moist convective processes. This scheme physically constrains the process of moist convection with the use of a simple bulk cloud model, which provides a basis for estimating convective-scale transports of heat, moisture, and other atmospheric constituents as well as the diabatic heating associated with condensation and the fallout of precipitation. This paper presents the formalism associated with this simple mass-flux approach and contrasts its behavior with the moist adiabatic adjustment procedure used in earlier models. The inclusion of this scheme significantly moistens and warms the model troposphere at all latitudes but particularly in the tropics. Additionally, the simulated magnitude, structure, and location of the large-scale mean circulations are generally improved. The sensitivity of the simulated climate to the formulation of the cloud model is also presented.

[1]  J. Kiehl,et al.  Sensitivity of a GCM climate simulation to differences in continental versus maritime cloud drop size , 1994 .

[2]  James J. Hack,et al.  Climate statistics from the National Center for Atmospheric Research community climate model CCM2 , 1994 .

[3]  James J. Hack,et al.  The simulated Earth radiation budget of the National Center for Atmospheric Research community climate model CCM2 and comparisons with the Earth Radiation Budget Experiment (ERBE) , 1994 .

[4]  B. Boville,et al.  Diurnal heating and cloudiness in the NCAR Community Climate Model (CCM2) , 1994 .

[5]  G. Bonan.  Comparison of the land surface climatology of the National Center for Atmospheric Research community climate model 2 at R15 and T42 resolutions , 1994 .

[6]  J. Kiehl,et al.  The simulated Earth radiation budget of the NCAR CCM2 and comparisons with the Earth Radiation Budget Experiment (ERBE) , 1994 .

[7]  Philip J. Rasch,et al.  Water vapor transport in the NCAR CCM2 , 1994 .

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

[9]  P. Rasch,et al.  Description of the NCAR community climate model (CCM2), June 1993. Technical note , 1993 .

[10]  W. Cotton,et al.  Storm and Cloud Dynamics , 1992 .

[11]  Kevin E. Trenberth,et al.  A global monthly sea surface temperature climatology , 1992 .

[12]  J. Kiehl,et al.  Comparison of the observed and calculated clear sky greenhouse effect: Implications for climate studies , 1992 .

[13]  S. Moorthi,et al.  Relaxed Arakawa-Schubert - A parameterization of moist convection for general circulation models , 1992 .

[14]  B. Briegleb.  Delta‐Eddington approximation for solar radiation in the NCAR community climate model , 1992 .

[15]  E. Trenberth,et al.  Global Analyses From ECMWF and Atlas of 1000 to 10 Mb Circulation Statistics , 1992 .

[16]  K. Emanuel.  A Scheme for Representing Cumulus Convection in Large-Scale Models , 1991 .

[17]  J. Kiehl,et al.  A new parameterization of the absorptance due to the 15‐μm band system of carbon dioxide , 1991 .

[18]  A. Holtslag,et al.  A High Resolution Air Mass Transformation Model for Short-Range Weather Forecasting , 1990 .

[19]  D. Legates,et al.  Mean seasonal and spatial variability in gauge‐corrected, global precipitation , 1990 .

[20]  M. Tiedtke.  A Comprehensive Mass Flux Scheme for Cumulus Parameterization in Large-Scale Models , 1989 .

[21]  Harshvardhan,et al.  Interactions among Radiation, Convection, and Large-Scale Dynamics in a General Circulation Model , 1989 .

[22]  A. Slingo.  A GCM Parameterization for the Shortwave Radiative Properties of Water Clouds , 1989 .

[23]  S. Williamson,et al.  Modifications and Enhancements to the NCAR Community Climate Model (CCM1) , 1989 .

[24]  M. Tiedtke.  Parameterization of Cumulus Convection in Large-Scale Models , 1988 .

[25]  Norman A. McFarlane,et al.  The Effect of Orographically Excited Gravity Wave Drag on the General Circulation of the Lower Stratosphere and Troposphere , 1987 .

[26]  The Effects of Cumulus Moisture Transports on the Simulation of Climate with a General Circulation Model , 1986 .

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

[28]  A. Betts.  A new convective adjustment scheme. Part I: Observational and theoretical basis , 1986 .

[29]  J. Hack,et al.  A Spectral Cumulus Parameterization for Use in Numerical Models of the Tropical Atmosphere , 1984 .

[30]  W. Frank,et al.  The Cumulus Parameterization Problem , 1983 .

[31]  Adrian Simmons,et al.  Numerical forecasts of stratospheric warming events using a model with a hybrid vertical coordinate , 1983 .

[32]  L. Williamson,et al.  Description of NCAR Community Climate Model (CCM0B) , 1983 .

[33]  E. Pitcher,et al.  The Significance of Thermodynamic Forcing by Cumulus Convection in a General Circulation Model , 1982 .

[34]  Stephen J. Lord,et al.  Interaction of a Cumulus Cloud Ensemble with the Large-Scale Environment. Part III: Semi-Prognostic Test of the Arakawa-Schubert Cumulus Parameterization , 1982 .

[35]  R. Anthes.  A Cumulus Parameterization Scheme Utilizing a One-Dimensional Cloud Model , 1977 .

[36]  Alan K. Betts,et al.  Parametric Interpretation of Trade-Wind Cumulus Budget Studies , 1975 .

[37]  H. Kuo.  Further Studies of the Parameterization of the Influence of Cumulus Convection on Large-Scale Flow , 1974 .

[38]  A. Arakawa,et al.  Interaction of a Cumulus Cloud Ensemble with the Large-Scale Environment, Part I , 1974 .

[39]  S. Esbensen,et al.  Determination of Bulk Properties of Tropical Cloud Clusters from Large-Scale Heat and Moisture Budgets , 1973 .

[40]  Edward N. Lorenz,et al.  The nature and theory of the general circulation of the atmosphere , 1967 .

[41]  Syukuro Manabe,et al.  SIMULATED CLIMATOLOGY OF A GENERAL CIRCULATION MODEL WITH A HYDROLOGIC CYCLE II. ANALYSIS OF THE TROPICAL ATMOSPHERE , 1965 .

[42]  H. Kuo.  On Formation and Intensification of Tropical Cyclones Through Latent Heat Release by Cumulus Convection , 1965 .