Comparison of cloud forcing derived from the Earth Radiation Budget Experiment with that simulated by the NCAR Community Climate Model

A comprehensive comparison of top of atmosphere radiative quantities from the Earth Radiation Budget Experiment (ERBE) with the same quantities from the latest version of the National Center for Atmospheric Research Community Climate Model (CCM) is presented. The ERBE data set offers a unique collection of top of atmosphere radiation fields for it includes clear-sky radiation fields that have in the past not been available for such comparisons. Comparison between ERBE clear-sky longwave fluxes and CCMl indicates larger outgoing flux in the model than measured by ERBE. This overestimation is ascribed to the prevalent dryness of the model. Comparison of clear sky albedo indicates good agreement over oceans and land. Total outgoing longwave flux also reflects the moisture deficiency of the model, but differences due to an underprediction of “effective” high cloud are also apparent. The clear-sky and total fluxes are combined to form the cloud radiative forcing from the ERBE data and the CCM. Comparison of shortwave cloud radiative forcing indicates deficiencies in the model where marine stratus clouds are absent. Large longwave cloud forcing over the tropical deep convective regions in Indonesia and South America are present in the model but are underestimated compared with the ERBE results. Three regions, located over Indonesia, the equatorial Pacific, and the North Atlantic, are considered in detail. For the Indonesian region where deep convection is present, we consider the statistical correlation between the longwave cloud forcing and the shortwave cloud forcing from the ERBE data and CCM. Results indicate a near cancellation between the SWCF and LWCF for these regions, whereas the model predicts a net cooling. Another major area of discrepancy is over the North Atlantic and Pacific oceans where ERBE shows that clouds significantly reduce the solar heating of the oceans. While the model simulates this cooling, the magnitude is underpredicted by more than a factor of 2.

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

[2]  Veerabhadran Ramanathan,et al.  The role of earth radiation budget studies in climate and general , 1987 .

[3]  R. Mobley,et al.  Monthly Average SeaSurface Temperatures and IcePack Limits on a 1 Global Grid , 1976 .

[4]  Robert D. Cess,et al.  Climate Change: An Appraisal of Atmospheric Feedback Mechanisms Employing Zonal Climatology. , 1976 .

[5]  G. Louis Smith,et al.  The Earth Radiation Budget Experiment: Science and implementation , 1986 .

[6]  Gerald L. Potter,et al.  Exploratory studies of cloud radiative forcing with a general circulation model , 1987 .

[7]  J. Kiehl,et al.  A parameterization for absorption due to the A, B, and γ oxygen bands , 1985 .

[8]  Bruce R. Barkstrom,et al.  The Earth Radiation Budget Experiment (ERBE). , 1984 .

[9]  Eric J. Pitcher,et al.  The Response of a Spectral General Circulation Model to Refinements in Radiative Processes , 1983 .

[10]  P. Webster,et al.  Tropical Upper-Tropospheric Extended Clouds: Inferences from Winter MONEX , 1980 .

[11]  S. Manabe,et al.  Cloud Feedback Processes in a General Circulation Model , 1988 .

[12]  F. O. Huck,et al.  First data from the earth radiation budget experiment (ERBE) , 1986 .

[13]  B. Barkstrom,et al.  Cloud-Radiative Forcing and Climate: Results from the Earth Radiation Budget Experiment , 1989, Science.

[14]  G. Ohring,et al.  The Effect of Changes in Cloud Amount on the Net Radiation at the Top of the Atmosphere , 1980 .

[15]  A. Mecherikunnel,et al.  The Earth Radiation Budget Experiment , 1988 .

[16]  J. Mahlman,et al.  Comprehensive Modeling of the Middle Atmosphere: The Influence of Horizontal Resolution , 1987 .

[17]  An approach for verifying clear-sky radiation models with ERBS scanner measurements , 1986 .

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

[19]  Veerabhadran Ramanathan,et al.  A nonisothermal emissivity and absorptivity formulation for water vapor , 1986 .

[20]  P. Rasch,et al.  Two-dimensional semi-Lagrangian trans-port with shape-preserving interpolation , 1989 .

[21]  A. Slingo,et al.  The response of a general circulation model to cloud longwave radiative forcing. I: Introduction and initial experiments , 1988 .

[22]  R. Cess,et al.  Solar absorption by atmospheric water vapor: a comparison of radiation models , 1985 .

[23]  Akio Arakawa,et al.  Finite-Difference Methods in Climate Modeling , 1988 .

[24]  Dennis L. Hartmann,et al.  Earth Radiation Budget data and climate research , 1986 .

[25]  D. Hartmann,et al.  On the Use of Earth Radiation Budget Statistics for Studies of Clouds and Climate , 1980 .

[26]  J. Hack,et al.  Description of the NCAR Community Climate Model (CCM1) , 1987 .

[27]  Patrick Minnis,et al.  Comparison of regional clear-sky albedos inferred from satellite-observations and model computations , 1986 .

[28]  Stephen B. Fels,et al.  The simplified exchange method revisited: An accurate, rapid method for computation of infrared cooling rates and fluxes , 1991 .

[29]  Harshvardhan,et al.  Earth radiation budget and cloudiness simulations with a general circulation model , 1989 .

[30]  L. F. Hubert,et al.  The Double Intertropical Convergence Zone-Fact or Fiction? , 1969 .

[31]  J. Wolski,et al.  Documentation of Radiation and Cloud Routines in the NCAR Community Climate Model (CCM1) , 1987 .

[32]  E. Trenberth,et al.  ECMWF Global Analyses 1979-1986: Circulation Statistics and Data Evaluation , 1988 .

[33]  Veerabhadran Ramanathan,et al.  Solar Absorption by Cirrus Clouds and the Maintenance of the Tropical Upper Troposphere Thermal Structure , 1989 .

[34]  Robert E. Dickinson,et al.  The Role of Stratospheric Ozone in the Zonal and Seasonal Radiative Energy Balance of the Earth-Troposphere System , 1979 .

[35]  A. Betts,et al.  Coupling of the radiative, convective, and surface fluxes over the equatorial Pacific , 1988 .

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

[37]  Robert M. Chervin,et al.  Cloudiness as a Climatic Feedback Mechanism: Effects on Cloud Amounts of Prescribed Global and Regional Surface Temperature Changes in the NCAR GCM , 1978 .

[38]  Andrew J. Heymsfield,et al.  A scheme for parameterizing ice cloud water content in general circulation models , 1990 .