• Barkstrom, B. R., and G. L. Smith, 1986: The Earth Radiation Budget Experiment: Science and implementation. Rev. Geophys, 24 , 379390.

    • Search Google Scholar
    • Export Citation
  • Bony, S., K. M. Lau, and Y. C. Sud, 1997: Sea surface temperature and large-scale circulation influences on tropical greenhouse effect and cloud radiative forcing. J. Climate, 10 , 20552077.

    • Search Google Scholar
    • Export Citation
  • Cess, R. D., and Coauthors, 1990: Intercomparison and interpretation of climate feedback processes in 19 atmospheric general circulation models. J. Geophys. Res, 95 , 1660116615.

    • Search Google Scholar
    • Export Citation
  • Collins, W., and Coauthors, cited 2003: Description of the NCAR Community Atmospheric Model (CAM2). [Available online at http://www.ccsm.ucar.edu/models/atm-cam/docs/cam2.0/description.pdf.].

    • Search Google Scholar
    • Export Citation
  • Cubasch, U., and Coauthors, 2001: Projection of future climate change. Climate Change 2001: The Scientific Basis, J. T. Houghton et al., Eds., Cambridge University Press, 527–582.

    • Search Google Scholar
    • Export Citation
  • Del Genio, A. D., M-S. Yao, W. Kovari, and K. K-W. Lo, 1996: A prognostic cloud water parameterization for global climate models. J. Climate, 9 , 270304.

    • Search Google Scholar
    • Export Citation
  • Hack, J. J., 1994: Parameterization of moist convection in the National Center for Atmospheric Research Community Climate Model (CCM2). J. Geophys. Res, 99 , 55515568.

    • Search Google Scholar
    • Export Citation
  • Hack, J. J., J. Hurrell, J. Rosinski, and J. Caron, cited 2002: The NCAR CGD annual scientific report 2002. [Available online at http://www.cgd.ucar.edu/asr02/CMS.htm.].

    • Search Google Scholar
    • Export Citation
  • Harrison, E. F., P. Minnis, B. R. Barkstrom, V. Ramanathan, R. D. Cess, and G. G. Gibson, 1990: Seasonal variation of cloud radiative forcing derived from the Earth Radiation Budget Experiment. J. Geophys. Res, 95 , 1868718703.

    • Search Google Scholar
    • Export Citation
  • Hartmann, D. L., A. M. Leslie, and Q. Fu, 2001: Tropical convection and the energy balance at the top of the atmosphere. J. Climate, 14 , 44954511.

    • Search Google Scholar
    • Export Citation
  • Kiehl, J. T., 1994: On the observed near cancellation between longwave and shortwave cloud forcing in tropical regions. J. Climate, 7 , 559565.

    • Search Google Scholar
    • Export Citation
  • Kiehl, J. T., J. J. Hack, G. B. Bonan, B. A. Boville, D. L. Williamson, and P. J. Rasch, 1998a: The National Center for Atmospheric Research Community Climate Model: CCM3. J. Climate, 11 , 11311150.

    • Search Google Scholar
    • Export Citation
  • Kiehl, J. T., J. J. Hack, and J. W. Hurrell, 1998b: The energy budget of the NCAR Community Climate Model: CCM3. J. Climate, 11 , 11511178.

    • Search Google Scholar
    • Export Citation
  • Klein, S. A., and D. L. Hartmann, 1993: The seasonal cycle of low stratiform clouds. J. Climate, 6 , 15871606.

  • Klein, S. A., and C. Jakob, 1999: Validation and sensitivities of frontal clouds simulated by the ECMWF model. Mon. Wea. Rev, 127 , 25142531.

    • Search Google Scholar
    • Export Citation
  • Loeb, N. G., K. Loukachine, N. Manalo-Smith, B. Wielicki, and D. Young, 2003: Angular distribution models for top-of-atmosphere radiative flux estimation from the Clouds and the Earth's Radiant Energy System instrument on the Tropical Rainfall Measuring Mission satellite. Part II: Validation. J. Appl. Meteor, 42 , 17481769.

    • Search Google Scholar
    • Export Citation
  • Norris, J. R., and C. P. Weaver, 2001: Improved techniques for evaluating GCM cloudiness applied to the NCAR CCM3. J. Climate, 14 , 25402550.

    • Search Google Scholar
    • Export Citation
  • Randall, D. A., and Coauthors, 2003: Confronting models with data: The GEWEX cloud systems study. Bull. Amer. Meteor. Soc, 84 , 455469.

    • Search Google Scholar
    • Export Citation
  • Rasch, P. J., and J. E. Kristjánsson, 1998: A comparison of the CCM3 model climate using diagnosed and predicted condensate parameterizations. J. Climate, 11 , 15871614.

    • Search Google Scholar
    • Export Citation
  • Rossow, W. B., and R. A. Schiffer, 1991: ISCCP cloud data products. Bull. Amer. Meteor. Soc, 72 , 220.

  • Rossow, W. B., A. W. Walker, D. Beuschel, and M. Roiter, 1996: International Satellite Cloud Climatology Project (ISSCP) description of new cloud datasets. WMO/TD 737, World Climate Research Programme (ICSU and WMO), 115 pp.

    • Search Google Scholar
    • Export Citation
  • Sanders, F., S. L. Mullen, and D. P. Baumhefner, 2000: Ensemble simulations of explosive cyclogenesis at ranges of 2–5 days. Mon. Wea. Rev, 128 , 29202934.

    • Search Google Scholar
    • Export Citation
  • Senior, C. A., and J. F. B. Mitchell, 1993: Carbon dioxide and climate: The impact of cloud parameterization. J. Climate, 6 , 393418.

  • Senior, C. A., and J. F. B. Mitchell, 1996: Cloud feedbacks in the unified UKMO GCM. Climate Sensitivity to Radiative Perturbations, Physical Mechanisms and Their Validation, H. Le Treut, Ed., Springer, 191– 202.

    • Search Google Scholar
    • Export Citation
  • Webb, M., C. Senior, S. Bony, and J. J. Morcrette, 2001: Combining ERBE and ISCCP data to assess clouds in the Hadley Centre, ECMWF and LMD atmospheric climate models. Climate Dyn, 17 , 905922.

    • Search Google Scholar
    • Export Citation
  • Xie, S. C., and M. H. Zhang, 2000: Impact of the convection triggering function on single-column model simulations. J. Geophys. Res, 105 , 1498314996.

    • Search Google Scholar
    • Export Citation
  • Yu, M., M. Doutriaux, G. Sèze, H. Le Treut, and M. Desbois, 1996: A methodology study of the validation of clouds in GCMs using ISCCP satellite observations. Climate Dyn, 12 , 389401.

    • Search Google Scholar
    • Export Citation
  • Zhang, G. J., and N. A. McFarlane, 1995: Sensitivity of climate simulations to the parameterization of cumulus convection in the Canadian Climate Centre general circulation model. Atmos.– Ocean, 33 , 407446.

    • Search Google Scholar
    • Export Citation
  • Zhang, M., W. Lin, C. Bretherton, J. J. Hack, and P. J. Rasch, 2003: A modified formulation of fractional stratiform condensation rate in the NCAR Community Atmospheric Model (CAM2). J. Geophys. Res.,108, 4035, doi:10.1029/2002JD002523.

    • Search Google Scholar
    • Export Citation
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Evaluation of Clouds and Their Radiative Effects Simulated by the NCAR Community Atmospheric Model Against Satellite Observations

W. Y. LinInstitute for Terrestrial and Planetary Atmospheres, State University of New York at Stony Brook, Stony Brook, New York

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M. H. ZhangInstitute for Terrestrial and Planetary Atmospheres, State University of New York at Stony Brook, Stony Brook, New York

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Abstract

Cloud climatology and the cloud radiative forcing at the top of the atmosphere (TOA) simulated by the NCAR Community Atmospheric Model (CAM2) are compared with satellite observations of cloud amount from the International Satellite Cloud Climatology Project (ISCCP) and cloud forcing data from the Earth Radiation Budget Experiment (ERBE). The comparison is facilitated by using an ISCCP simulator in the model as a run-time diagnostic package. The results show that in both winter and summer seasons, the model substantially underestimated total cloud amount in the storm tracks and in the subtropical dry regions of the two hemispheres, and it overestimated total cloud amount in the tropical convection centers. The model, however, simulates reasonable cloud radiative forcing at the TOA at different latitudes.

The differences of cloud vertical structures and their optical properties are analyzed between the model and the data for three regions selected to represent the storm tracks: the convective Tropics and the subtropical subsidence regions. Major cloud biases are identified as follows: the model overestimated high thin cirrus, high-top optically thick clouds, and low-top optically thick clouds, while it significantly underestimated middle- and low-top clouds with intermediate and small optical thickness. These multiple cloud biases compensate for each other to produce reasonable cloud forcing in the following way: for the longwave cloud forcing, excessive high clouds compensate for significantly deficient middle and low clouds; for the shortwave cloud forcing, excessive optically thick clouds offset significantly deficient optically intermediate and thin clouds. Possible causes of model biases are discussed.

Corresponding author address: Dr. Wuyin Lin, ITPA/MSRC, State University of New York at Stony Brook, Stony Brook, NY 11794-5000. Email: wlin@atmsci.msrc.sunysb.edu

Abstract

Cloud climatology and the cloud radiative forcing at the top of the atmosphere (TOA) simulated by the NCAR Community Atmospheric Model (CAM2) are compared with satellite observations of cloud amount from the International Satellite Cloud Climatology Project (ISCCP) and cloud forcing data from the Earth Radiation Budget Experiment (ERBE). The comparison is facilitated by using an ISCCP simulator in the model as a run-time diagnostic package. The results show that in both winter and summer seasons, the model substantially underestimated total cloud amount in the storm tracks and in the subtropical dry regions of the two hemispheres, and it overestimated total cloud amount in the tropical convection centers. The model, however, simulates reasonable cloud radiative forcing at the TOA at different latitudes.

The differences of cloud vertical structures and their optical properties are analyzed between the model and the data for three regions selected to represent the storm tracks: the convective Tropics and the subtropical subsidence regions. Major cloud biases are identified as follows: the model overestimated high thin cirrus, high-top optically thick clouds, and low-top optically thick clouds, while it significantly underestimated middle- and low-top clouds with intermediate and small optical thickness. These multiple cloud biases compensate for each other to produce reasonable cloud forcing in the following way: for the longwave cloud forcing, excessive high clouds compensate for significantly deficient middle and low clouds; for the shortwave cloud forcing, excessive optically thick clouds offset significantly deficient optically intermediate and thin clouds. Possible causes of model biases are discussed.

Corresponding author address: Dr. Wuyin Lin, ITPA/MSRC, State University of New York at Stony Brook, Stony Brook, NY 11794-5000. Email: wlin@atmsci.msrc.sunysb.edu

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