• Barkstrom, B. R., 1984: The Earth Radiation Budget Experiment (ERBE). Bull. Amer. Meteor. Soc.,65, 1170–1185.

  • Bergman, J. W., and M. L. Salby, 1996: Diurnal variations of cloud cover and their relationship to climatological conditions. J. Climate,9, 2802–2820.

  • Briegleb, B. P., 1992: Delta–Eddington approximation for solar radiation in the NCAR community climate model. J. Geophys. Res.,97, 7603–7612.

  • Cess, R. D., and G. L. Potter, 1987: Exploratory studies of cloud radiative forcing with a general circulation model. Tellus,39A, 460–473.

  • ——, and Coauthors, 1990: Intercomparison and interpretation of climate feedback processes in 19 atmospheric general circulation models. J. Geophys. Res.,95, 16 601–16 615.

  • ——, and Coauthors, 1996: Cloud feedback in atmospheric general circulation models: An update. J. Geophys. Res.,101, 12 791–12 794.

  • Cubasch, U., R. D. Cess, F. Bretherton, H. Cattle, J. T. Houghton, J. F. B. Mitchell, D. Randall, E. Roeckner, J. D. Woods, and T. Yamanouchi, 1990: Processes and modeling. Climate Change: The IPCC Scientific Assessment, J. T. Houghton, G. J. Jenkins, and J. J. Ephraums, Eds., Cambridge University Press, 69–91.

  • Cutrim, E., D. W. Martin, and R. Rabin, 1995: Enhancement of cumulus clouds over deforested lands in Amazonia. Bull. Amer. Meteor. Soc.,76, 1801–1805.

  • Dhuria, H. L., and H. L. Kyle, 1990: Cloud types and the tropical Earth radiation budget. J. Climate,3, 1409–1434.

  • Gupta, S. K., W. F. Staylor, W. L. Darnell, A. C. Wilber, and N. A. Ritchey, 1993: Seasonal variation of surface and atmospheric cloud radiative forcing over the globe derived from satellite data. J. Geophys. Res.,98, 20 761–20 778.

  • Hack, J. J., B. A. Boville, B. P. Briegleb, J. T. Kiehl, P. J. Rasch, and D. L. Williamson, 1993: Description of the NCAR community climate model (CCM2). NCAR Tech. Note NCAR/TN-382+STR, 108 pp. [Available from National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307.].

  • Harrison, E. F., D. R. Brooks, P. Minnis, B. A. Wielicki, W. F. Staylor, G. G. Gibson, D. F. Young, F. M. Denn, and the ERBE Science Team, 1988: First estimates of the diurnal variation of longwave radiation from the multiple-satellite Earth Radiation Budget Experiment (ERBE). Bull. Amer. Meteor. Soc.,69, 1144–1151.

  • ——, 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, 18 687–18 703.

  • Hartmann, D. L., and E. E. Recker, 1986: Diurnal variation of outgoing longwave radiation in the tropics. J. Climate Appl. Meteor.,25, 800–812.

  • ——, and D. Doelling, 1991: On the net radiative effectiveness of clouds. J. Geophys. Res.,96, 869–891.

  • ——, K. J. Kowalewsky, and M. L. Michelsen, 1991: Diurnal variations of outgoing longwave radiation and albedo from ERBE scanner data. J. Climate,4, 598–617.

  • ——, M. E. Ockert-Bell, and M. L. Michelsen, 1992: The effect of cloud type on Earth’s energy budget: Global analysis. J. Climate,5, 1282–1304.

  • Kiehl, J. T., and V. Ramanathan, 1990: Comparison of cloud radiative forcing derived from the Earth Radiation Budget Experiment with that simulated by the NCAR Community Climate Model. J. Geophys. Res.,95, 11 679–11 698.

  • ——, and B. P. Briegleb, 1991: A new parameterization of the absorption due to the 15-μm band system of carbon dioxide. J. Geophys. Res.,96, 9013–9019.

  • Liou, K. N., 1992: Radiation and Cloud Processes in the Atmosphere. Oxford University Press, 486 pp.

  • Minnis, P., and E. F. Harrison, 1984: Diurnal variability of regional cloud and clear-sky radiative parameters derived from GOES data. Part II: November 1978 cloud distributions. J. Climate Appl. Meteor.,23, 1012–1031.

  • Ockert-Bell, M. E., and D. L. Hartmann, 1992: The effect of cloud type on Earth’s energy balance: Results for selected regions. J. Climate,5, 1157–1171.

  • Ramanathan, V., and P. Downey, 1986: A nonisothermal emissivity and absorptivity formulation for water vapor. J. Geophys. Res.,91, 8649–8666.

  • ——, R. D. Cess, E. F. Harrison, P. Minnis, B. R. Barkstrom, E. Ahmad, and D. L. Hartmann, 1989: Cloud radiative forcing and climate: Results from the Earth Radiation Budget Experiment. Science,243, 57–63.

  • Randall, D. A., J. A. Abeles, and T. G. Corsetti, 1985: Seasonal simulations of planetary boundary layer and planetary stratocumulus clouds with a general circulation model. J. Atmos. Sci.,42, 641–676.

  • ——, Harshvardhan, and D. A. Dazlich, 1991: Diurnal variability of the hydrological cycle in a general circulation model. J. Atmos. Sci.,48, 40–62.

  • Rossow, W. B., and R. A. Schiffer, 1991: ISCCP cloud data products. Bull. Amer. Meteor. Soc.,72, 2–20.

  • ——, and L. C. Garder, 1993: Cloud detection using satellite measurement of infrared and visible radiances for ISCCP. J. Climate,6, 2341–2369.

  • Rozendaal, M. A., C. B. Leovy, and S. A. Klein, 1995: An observational study of diurnal variations of marine stratiform cloud. J. Climate,8, 1795–1809.

  • Salby, M. L., H. H. Hendon, K. Woodberry, and K. Tanaka, 1991: Analysis of global cloud imagery from multiple satellites. Bull. Amer. Meteor. Soc.,72, 467–475.

  • Stephens, G. L., 1978: Radiation profiles in extended water clouds. I: Theory. J. Atmos. Sci.,35, 2111–2122.

  • Tian, L., and J. A. Curry, 1989: Cloud overlap statistics. J. Geophys. Res.,94, 9925–9935.

  • Warren, S. G., C. J. Hahn, J. London, R. M. Chervin, and R. L. Jenne, 1986: Global distribution of total cloud cover and cloud type over land. NCAR Tech. Note NCAR/TN-273+STR, 29 pp, 199 maps. [Available from National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307.].

  • ——, ——, ——, ——, and ——, 1988: Global distribution of total cloud cover and cloud type over ocean. NCAR Tech. Note NCAR/TN-317+STR, 42 pp, 170 maps. [Available from National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307.].

  • Wielicki, B. A., R. D. Cess, M. D. King, D. A. Randall, and E. F. Harrison, 1995: Mission to planet Earth: Role of clouds and radiation in climate. Bull. Amer. Meteor. Soc.,76, 2125–2153.

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The Role of Cloud Diurnal Variations in the Time-Mean Energy Budget

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  • 1 Center for Atmospheric Theory and Analysis, University of Colorado, Boulder, Colorado
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Abstract

The contribution to time-mean energetics from cloud diurnal variations is investigated. Cloud diurnal contributions to radiative fluxes follow as the differences between time-mean radiative fluxes based on diurnally varying cloud properties and those based on fixed cloud properties. Time-mean energetics under both conditions are derived from an observationally driven radiative transfer calculation in which cloud cover, temperature, and moisture are prescribed from satellite observations.

Cloud diurnal contributions to time-mean energetics arise from the nonlinear dependence of radiative fluxes on diurnally varying properties. Diurnal variations of cloud fractional coverage and solar flux are the main factors of the cloud diurnal contributions to shortwave (SW) flux, although the diurnal variation of cloud type is also important. The cloud diurnal contribution to longwave (LW) flux at the top of the atmosphere (TOA) is produced by diurnal variations of cloud fractional coverage, cloud-top height, and surface temperature. The cloud diurnal contribution to LW flux at the surface is produced by diurnal variations of cloud fractional coverage and cloud-base height. Cloud diurnal contributions to SW fluxes at the surface and TOA are much larger than the contribution to SW atmospheric absorption. The contribution to radiative heating in the atmosphere is concentrated inside the cloud layer. Its vertical profile changes sign, so the cloud diurnal contribution to atmospheric energetics is significantly larger than is implied by the column average.

Cloud diurnal contributions to SW flux at the surface and TOA are 5–15 W m−2 over continental and maritime subsidence regions, where the diurnal variation of cloud fractional coverage is large. The contributions to LW fluxes are 1–5 W m−2 over continental regions, where diurnal variations of cloud fractional coverage and surface temperature are large. A cancellation between contributions of opposite sign makes the cloud diurnal contributions to globally averaged energetics much smaller than regional contributions. However, a shift in regional climate from one dominated by high clouds to one dominated by low clouds can alter time-mean surface energetics by as much as 20 W m−2.

* Current affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado.

Corresponding author address: Dr. John W. Bergman, CIRES/CDC Campus Box 449, University of Colorado, Boulder, CO 80309-0449.

Email: jwb@cdc.noaa.gov

Abstract

The contribution to time-mean energetics from cloud diurnal variations is investigated. Cloud diurnal contributions to radiative fluxes follow as the differences between time-mean radiative fluxes based on diurnally varying cloud properties and those based on fixed cloud properties. Time-mean energetics under both conditions are derived from an observationally driven radiative transfer calculation in which cloud cover, temperature, and moisture are prescribed from satellite observations.

Cloud diurnal contributions to time-mean energetics arise from the nonlinear dependence of radiative fluxes on diurnally varying properties. Diurnal variations of cloud fractional coverage and solar flux are the main factors of the cloud diurnal contributions to shortwave (SW) flux, although the diurnal variation of cloud type is also important. The cloud diurnal contribution to longwave (LW) flux at the top of the atmosphere (TOA) is produced by diurnal variations of cloud fractional coverage, cloud-top height, and surface temperature. The cloud diurnal contribution to LW flux at the surface is produced by diurnal variations of cloud fractional coverage and cloud-base height. Cloud diurnal contributions to SW fluxes at the surface and TOA are much larger than the contribution to SW atmospheric absorption. The contribution to radiative heating in the atmosphere is concentrated inside the cloud layer. Its vertical profile changes sign, so the cloud diurnal contribution to atmospheric energetics is significantly larger than is implied by the column average.

Cloud diurnal contributions to SW flux at the surface and TOA are 5–15 W m−2 over continental and maritime subsidence regions, where the diurnal variation of cloud fractional coverage is large. The contributions to LW fluxes are 1–5 W m−2 over continental regions, where diurnal variations of cloud fractional coverage and surface temperature are large. A cancellation between contributions of opposite sign makes the cloud diurnal contributions to globally averaged energetics much smaller than regional contributions. However, a shift in regional climate from one dominated by high clouds to one dominated by low clouds can alter time-mean surface energetics by as much as 20 W m−2.

* Current affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado.

Corresponding author address: Dr. John W. Bergman, CIRES/CDC Campus Box 449, University of Colorado, Boulder, CO 80309-0449.

Email: jwb@cdc.noaa.gov

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