Climate Dynamics

, Volume 22, Issue 2–3, pp 71–86 | Cite as

On dynamic and thermodynamic components of cloud changes

  • S. Bony
  • J.-L. Dufresne
  • H. Le Treut
  • J.-J. Morcrette
  • C. Senior
Article

Abstract

Clouds are sensitive to changes in both the large-scale circulation and the thermodynamic structure of the atmosphere. In the tropics, temperature changes that occur on seasonal to decadal time scales are often associated with circulation changes. Therefore, it is difficult to determine the part of cloud variations that results from a change in the dynamics from the part that may result from the temperature change itself. This study proposes a simple framework to unravel the dynamic and non-dynamic (referred to as thermodynamic) components of the cloud response to climate variations. It is used to analyze the contrasted response, to a prescribed ocean warming, of the tropically-averaged cloud radiative forcing (CRF) simulated by the ECMWF, LMD and UKMO climate models. In each model, the dynamic component largely dominates the CRF response at the regional scale, but this is the thermodynamic component that explains most of the average CRF response to the imposed perturbation. It is shown that this component strongly depends on the behaviour of the low-level clouds that occur in regions of moderate subsidence (e.g. in the trade wind regions). These clouds exhibit a moderate sensitivity to temperature changes, but this is mostly their huge statistical weight that explains their large influence on the tropical radiation budget. Several propositions are made for assessing the sensitivity of clouds to changes in temperature and in large-scale motions using satellite observations and meteorological analyses on the one hand, and mesoscale models on the other hand.

Keywords

Outgoing Longwave Radiation Cloud Property Cloud Radiative Force Cloud Response Climate Perturbation 

Notes

Acknowledgements.

This work benefited from discussions with Kerry Emanuel, Jean-Yves Grandpeix, Christian Jakob, Laurent Li, Mark Webb and Yun-Ichi Yano, and from comments by anonymous reviewers. Part of this study was supported by the Environmental Program of the Commission of the European Communities (project ENV4-CT95-0126 entitled Cloud Feedbacks and Validation). French participants acknowledge the Programme National d’Etude Du Climat (PNEDC).

References

  1. Allan RP, Slingo A (2002) Can current climate model forcings explain the spatial and temporal signatures of decadal olr variations? Geophys Res Lett 29: 10,1029–10,1032CrossRefGoogle Scholar
  2. Allan RP, Slingo A, Ringer MA (2002) Influence of dynamics on the changes in tropical cloud radiative forcing during the 1998 El-Niño. J Clim 15: 1979–1986CrossRefGoogle Scholar
  3. Barkstrom BR (1984) The Earth Radiation Budget Experiment (ERBE). Bull Am Metropol Soc 65: 1170–1185CrossRefGoogle Scholar
  4. Bony S, Collins WC, Fillmore D (2000) Indian ocean low clouds during the winter monsoon. J Clim 13: 2028–2043CrossRefGoogle Scholar
  5. Bony S, Lau K-M, Sud YC (1997) Sea surface temperature and large-scale circulation influences on tropical greenhouse effect and cloud radiative forcing. J Clim 10: 2055–2077CrossRefGoogle Scholar
  6. Bretherton CS, Sobel AH (2002) A simple model of a convectively coupled Walker circulation using the weak temperature gradient approximation. J Clim 15: 2907–2920CrossRefGoogle Scholar
  7. Chen J, Carlson BE, Del Genio AD (2002) Evidence for strengthening of the tropical general circulation in the 1990s. Science 295: 838–841CrossRefPubMedGoogle Scholar
  8. Chéruy F, Chevallier F (2000) Regional and seasonal variations of the clear sky atmospheric longwave cooling over tropical oceans. J Clim 13: 2863–2875CrossRefGoogle Scholar
  9. CLIMAP Project Members (1981) Seasonal reconstruction of the earths surface at the last glacial maximum. Map and Chart Series, 18 pp, Geological Society of AmericaGoogle Scholar
  10. Coakley JA, Baldwin DG (1984) Towards the objective analysis of clouds from imagery data. J Clim Appl Meteorol 23: 1065–1099CrossRefGoogle Scholar
  11. Del Genio AD, Kovari W (2002) Climatic properties of tropical precipitating convection under varying environmnetal conditions. J Clim 15: 2597–2615CrossRefGoogle Scholar
  12. Del Genio AD, Yao M-S, Kovari W, Lo KK-W (1996) A prognostic cloud water parametrization for global climate models. J Clim 9: 270–304CrossRefGoogle Scholar
  13. Dhuria HL, Kyle HL (1990) Cloud types and the tropical earth radiation budget. J Clim 3: 1409–1434CrossRefGoogle Scholar
  14. Emanuel KA (1994) Atmospheric convection. Oxford University Press, Oxford, UKGoogle Scholar
  15. Emanuel KA, Pierrehumbert RT (1996) Microphysical and dynamical control of tropospheric water vapour. In: Crutzen PJ, Ramanathan V (eds) Clouds, Chemistry, and Climate. Springer-Berlin, Heidelberg, New York, pp 264Google Scholar
  16. Emanuel KA, Zivkovic-Rothman M (1999) Development and evaluation of a convection scheme for use in climate models. J Atmos Sci 56: 1766–1782CrossRefGoogle Scholar
  17. Emanuel KA, Neelin JD, Bretherton CS (1994) On large-scale circulations in convecting atmospheres. Q J R Meteorol Soc 120: 1111–1143CrossRefGoogle Scholar
  18. Folkins I, Braun C (2003) Tropical rainfall and boundary layer moist entropy. J Clim 16: 1807–1820CrossRefGoogle Scholar
  19. Fu Q, Baker M, Hartmann DL (2002) Tropical cirrus and water vapour: an effective Earth infrared iris? Atmos Chem Phys 2: 31–37Google Scholar
  20. GEWEX Cloud System Science Team (1993) The GEWEX Cloud System Study (GCSS). Bull Am Meteorol Soc 74: 387–389CrossRefGoogle Scholar
  21. Gibson JK, Kallberg P, Uppala S, Noumura A, Hernandez A, Serrano E (1997) ERA description. ECMWF Re-Analysis Project Report Series 77 pp ECMWF, Reading, UKGoogle Scholar
  22. Hartmann DL, Michelsen ML (1993) Large-scale effects on the regulation of tropical sea surface temperature. J Clim 6: 2049–2062CrossRefGoogle Scholar
  23. Hartmann DL, Moy LA, Fu Q (2001) Tropical convection and the energy balance at the top of the atmosphere. J Clin 14: 4495–4511CrossRefGoogle Scholar
  24. Kalnay E and co authors (1996) The NCEP/NCAR 40-year reanalysis project. Bull Am Meteorol Soc 77: 437–471CrossRefGoogle Scholar
  25. Klein SA, Hartmann DL (1993) The seasonal cycle of low stratiform clouds. J Clim 6: 1587–1606CrossRefGoogle Scholar
  26. Klein SA, Jakob C (1999) Validation and sensitivities of frontal clouds simulated by the ECMWF model. Mon Weather Rev 127: 2514–2531CrossRefGoogle Scholar
  27. Larson K, Hartmann DL, Klein SA (1999) The role of clouds, water vapour, circulation, boundary layer structure in the sensitivity of the tropical climate. J Clim 12: 2359–2374CrossRefGoogle Scholar
  28. Lau K-M, Sui CH, Chou MD, Tau WK (1994) An inquiry into the cirrus-thermostat effect for tropical sea surface temperature. Geophys Res Lett 21: 1157–1160Google Scholar
  29. Lau K-M, Wu HT, Bony S (1997) The role of large-scale atmospheric circulation in the relationship between tropical convection and sea surface temperature. J Clim 10: 381–392CrossRefGoogle Scholar
  30. LeTreut H, McAvaney B (2000) A model intercomparison of equilibrium climate change in response to CO2 doubling. Note du Pôle de Modélisation de l’IPSL, 2000Google Scholar
  31. Levitus S, Antonov JI, Boyer TP, Stephens C (2000) Warming of the world ocean. Science 287: 2225–2229CrossRefGoogle Scholar
  32. Lin B, Wielicki BA, Chambers LH, Hu Y, Xu K-M (2002) The Iris hypotehsis: a negative or positive cloud feedback? J Clim 15: 3–7CrossRefGoogle Scholar
  33. Lindzen RS, Nigam S (1987) On the Role of Sea Surface Temperature Gradients in Forcing Low-Level Winds and Convergence in the tropics. J Atmos Sci 44: 2418–2436CrossRefGoogle Scholar
  34. Lindzen RS, Chou MD, Hou AY (2001) Does the Earth have an adaptative infrared iris? Bull Am Meteorol Soc 82: 417–432CrossRefGoogle Scholar
  35. Miller RL (1997) Tropical thermostats and low cloud cover. J Clim 10: 409–440CrossRefGoogle Scholar
  36. Morcrette J-J (1991) Evaluation of model-generated cloudiness: satellite observed and model generated diurnal variability of brightness temperature. Mon Weather Rev 119: 1205–1224CrossRefGoogle Scholar
  37. Norris JR (1998) Low cloud type over the ocean from surface observations. Part II: geographical and seasonal variations. J Clim 11: 383–403CrossRefGoogle Scholar
  38. Norris JR, Weaver CP (2001) Improved techniques for evaluating GCM cloudiness applied to the NCAR CCM3. J Clim 14: 2540–2550CrossRefGoogle Scholar
  39. Pierrehumbert RT (1995) Thermostats, radiator fins, the local runaway greenhouse. J Atmos Sci 52: 1784–1806CrossRefGoogle Scholar
  40. Pierrehumbert RT, Roca R (1998) Evidence for control of atlantic subtropical humidity by large scale advection. Geophys Res Lett 25: 4537–4540Google Scholar
  41. Pope VD, Gallani ML, Rowntree PR, Stratton RA (2000) The impact of new physical parametrizations in the Hadley Centre climate model. Clim Dyn 16: 123–146CrossRefGoogle Scholar
  42. Ramanathan V, Collins W (1991) Thermodynamic regulation of ocean warming by cirrus clouds deduced from observations of the 1987 el-niño. Nature 351: 27–32CrossRefGoogle Scholar
  43. Salathe E, Hartmann DL (1997) A trajectory analysis of tropical upper-tropospheric moisture and convection. J Clim 10: 2533–2547CrossRefGoogle Scholar
  44. Schubert SD, Pfaendtner J, Rood R (1993) An assimilated dataset for Earth science applications. Bull Am Meteorol Soc 74: 2331–2342CrossRefGoogle Scholar
  45. Sud YC, Walker GK, Lau KM (1999) Mechanisms regulating sea surface temperatures and deep convection in the tropics. Geophys Res Lett 26: 1019–1022CrossRefGoogle Scholar
  46. Tompkins AM (2001) On the relationship between tropical convection and sea surface temperature. J Clim 14: 633–637CrossRefGoogle Scholar
  47. Tompkins AM, Craig GC (1999) Sensitivity of tropical convection to sea surface temperature in the absence of large-scale flow. J Clim 12: 462–476CrossRefGoogle Scholar
  48. Waliser DE (1996) Formation and limiting mechanism for very high sst: linking the dynamics and thermodynamics. J Clim 9: 161–188CrossRefGoogle Scholar
  49. Waliser DE, Graham NE (1993) Convective cloud systems and warm-pool sea surface temperatures: coupled interactions and self-regulation. J Geophys Res 98: 12,881–12,893Google Scholar
  50. Webb M, Senior C, Bony S, Morcrette J-J (2001) Combining ERBE and ISCCP data to assess clouds in the Hadley Centre. ECMWF and LMD atmospheric climate models. Clim Dyn 17: 905–922CrossRefGoogle Scholar
  51. Wielicki BA, Wong T, Allan RP, Slingo A, Kiehl JT, Soden BJ, Gordon CT, Miller AJ, Yang, S-K, Randall DA, Robertson F, Susskind J, Jacobowitz H (2002) Evidence for large decadal variability in the tropical mean radiative energy budget. Science 295: 841–844CrossRefPubMedGoogle Scholar
  52. Williams KD, Ringer MA, Senior CA (2003) Evaluating the cloud response to climate change and current climate variability. Clim Dyn 20:705–721Google Scholar
  53. Wu X, Moncrieff MW (1999) Effects of sea surface temperature and large-scale dynamics on the thermodynamic equilibrium state and convection over the tropical western pacific. J Geophys Res 104(D6): 6093–6100CrossRefGoogle Scholar
  54. Wu X, Hall WD, Grabowski WW, Moncrieff MW, Collins WD, Kiehl JT (1999) Long-term behavior of cloud systems in TOGA COARE and their interactions with radiative and surface processes. Part II: effects of cloud microphysics on cloud-radiation interaction. J Geophys Res 56: 3177–3195CrossRefGoogle Scholar
  55. Yao M-S, Del Genio AD (2001) Effects of cloud parameterization on the simulation of climate changes in the GISS GCM. Part II: sea surface temperature and cloud feedbacks. J Clim 15: 2491–2503CrossRefGoogle Scholar
  56. Yin JH, Battisti DS (2001) The importance of tropical sea surface temperature patterns in simulations of last glacial maximum climate. J Clim 14: 565–581CrossRefGoogle Scholar
  57. Yu W, Doutriaux M, Sèze G, LeTreut H, Desbois M (1996) A methodology study of the validation of clouds in GCMs using ISCCP satellite observations. Clim Dyn 12: 389–401CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • S. Bony
    • 1
  • J.-L. Dufresne
    • 1
  • H. Le Treut
    • 1
  • J.-J. Morcrette
    • 2
  • C. Senior
    • 3
  1. 1.Laboratoire de Météorologie DynamiqueInstitut Pierre Simon Laplace (LMD/IPSL)Paris cedex 05France
  2. 2.European Centre for Medium Range Weather Forecasts ReadingEngland
  3. 3.Hadley CentreMeteorological OfficeBracknellUK

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