Cloud radiative forcing of subtropical low level clouds in global models
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Simulations of subtropical marine low clouds and their radiative properties by nine coupled ocean-atmosphere climate models participating in the fourth assesment report (AR4) of the intergovernmental panel on climate change (IPCC) are analyzed. Satellite observations of cloudiness and radiative fluxes at the top of the atmosphere (TOA) are utilized for comparison. The analysis is confined to the marine subtropics in an attempt to isolate low cloudiness from tropical convective systems. All analyzed models have a negative bias in the low cloud fraction (model mean bias of −15%). On the other hand, the models show an excess of cloud radiative cooling in the region (model mean excess of 13 W m−2). The latter bias is shown to mainly originate from too much shortwave reflection by the models clouds rather than biases in the clear-sky fluxes. These results confirm earlier studies, thus no major progress in simulating the marine subtropical clouds is noted. As a consequence of the combination of these two biases, this study suggests that all investigated models are likely to overestimate the radiative response to changes in low level subtropical cloudiness.
KeywordsLow clouds Cloud radiative forcing Global climate models Stratocumulus Cloud feedback ERBE ISCCP IPCC
Thanks go to Frida Bender for good discussions and critical comments. The ERBE-data were obtained from the NASA Langley Research Center Atmospheric Sciences Data Center. The climatological monthly mean ISCCP D2 data were obtained from the International Satellite Cloud Climatology Project web site http://isccp.giss.nasa.gov maintained by the ISCCP research group at the NASA Goddard Institute for Space Studies, New York, NY on March, 2005. ICOADS data provided by the NOAA-CIRES Climate Diagnostics Center, Boulder, Colorado, USA, from their Web site at http://www.cdc.noaa.gov/. We acknowledge the international modeling groups for providing their data for analysis, the Program for Climate Model Diagnosis and Intercomparison (PCMDI) for collecting and archiving the model data, the JSC/CLIVAR Working Group on Coupled Modelling (WGCM) and their Coupled Model Intercomparison Project (CMIP) and Climate Simulation Panel for organizing the model data analysis activity, and the IPCC WG1 TSU for technical support. The IPCC Data Archive at Lawrence Livermore National Laboratory is supported by the Office of Science, U.S. Department of Energy.
- Cess RD, Potter GL, Blanchet JP, Boer GJ, Del Genio AD, Déqué M, Dymnikov V, Galin V, Gates WL, Ghan SJ, Kiehl JT, Lacis AA, Le Treut H, McAvaney BJ, Meleshko VP, Mitchell JFB, Morcrette J-J, Randall DA, Rikus L, Roeckner E, Royer JF, Schlese U, Sheinin DA, Slingo A, Sokolov AP, Taylor KE, Washington WM, Wetherald RT, Yagai I (1990) Intercomparison and interpretation of climate feedback processes in 19 atmospheric general circulation models. J Geophys Res 95(D10):16601–16615CrossRefGoogle Scholar
- Cess RD, Zhang MH, Ingram WJ, Potter GL, Alekseev V, Barker HW, Cohen-Solal E, Colman RA, Dazlich DA, Del Genio AD, Dix MR, Esch M, Fowler LD, Fraser JR, Galin V, Gates WL, Hack JJ, Kiehl JT, Le Treut H, Lo KK-W, McAvaney BJ, Meleshko VP, Morcrette J-J, Randall DA, Roeckner E, Royer J-F, Schlesinger ME, Sporyshev PV, Timbal B, Volodin EM, Taylor KE, Wang W, Wetherald RT (1996) Cloud feedback in atmospheric general circulation models: an update. J Geophys Res 101(D8):12791–12794CrossRefGoogle Scholar
- Collins W, Rasch P, Boville B, Hack J, McCaa J, Williamson D, Kiehl J, Briegleb B, Bitz C, Lin S, Zhang M, Dai Y (2004) Description of the NCAR community atmosphere model (CAM 3.0), tech note TN-464+STR. Technical report. National Center For Atmospheric Research, BoulderGoogle Scholar
- Delworth TL, Broccoli AJ, Rosati A, Stouffer RJ, Balaji V, Beesley JA, Cooke WF, Dixon KW, Dunne J, Dunne KA, Durachta JW, Findell KL, Ginoux P, Gnanadesikan A, Gordon CT, Griffies SM, Gudgel R, Harrison MJ, Held IM, Hemler RS, Horowitz LW, Klein SA, Knutson TR, Kushner PJ, Langenhorst AR, Lee H-C, Lin S-J, Lu J, Malyshev SL, Milly PCD, Ramaswamy V, Russell J, Schwarzkopf MD, Shevliakova E, Sirutis JJ, Spelman MJ, Stern WF, Winton M, Wittenberg AT, Wyman B, Zeng F Zhang R (2006) GFDL’s CM2 global coupled climate models. Part I: formulation and simulation characteristics. J Clim 19:643–674CrossRefGoogle Scholar
- Gnanadesikan A, Dixon KW, Griffies SM, V Balaji, Barreiro M, Beesley JA, Cooke WF, Delworth TL, Gerdes R, Harrison MJ, Held IM, Hurlin WJ, Lee H-C, Liang Z, Nong G, Pacanowski RC, Rosati A, Russell J, Samuels BL, Song Q, Spelman MJ, Stouffer RJ, Sweeney CO, Vecchi G, Winton M, Wittenberg AT, Zeng F, Zhang R, Dunne JP (2006) GFDL’s CM2 global coupled climate models. Part II: the baseline ocean simulation. J Clim 19:675–697CrossRefGoogle Scholar
- IPCC, Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt K, Tignor M, H M (eds) (2007) IPCC: climate change 2007: the scientific basis. Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change. Technical report. Cambridge University Press, Cambridge, p 996Google Scholar
- K-1 Model Developers (2004) K-1 coupled model (MIROC) description. Hasumi H, Emori S (eds) Tech. report 1. Technical report, Center for Climate System Research. University of Tokyo, TokyoGoogle Scholar
- Marti O, Bellier J, Benshila R, Bony S, Brockmann P, Cadulle P, Caubel A, Denvil S, Dufresne J, Fairhead L, Filiberti M-A, Fichefet T, Friedlingstein P, Grandpeix J-Y, Hourdin F, Krinner G, Lévy C, Musat I, Talandier C (2005) The new IPSL climate system model: IPSL-CM4. Report 26. Technical report, Institut Pierre Simon Laplace, ParisGoogle Scholar
- Webb MJ, Senior CA, Sexton DMH, Ingram WJ, Williams KD, Ringer MA, McAvaney BJ, Colman R, Soden BJ, Gudgel R, Knutson T, Emori S, Ogura T, Tsushima Y, Andronova N, Li B, Musat I, Bony S, Taylor KE (2006) On the contribution of local feedback mechanisms to the range of climate sensitivity in two GCM ensembles. Clim Dyn 27:17–38CrossRefGoogle Scholar
- Wyant M, Bretherton C, Bacmeister J, Kiehl J, Held I, Zhao M, Klein S, Soden B (2006) A comparison of low-latitude cloud properties and their response to climate change in three agcms sorted into regimes using mid-tropospheric vertical. Clim Dyn 27:261–279. doi:10.1007/s00382-006-0138-4 CrossRefGoogle Scholar
- Zhang MH, Lin WY, Klein SA, Bacmeister JT, Bony S, Cederwall RT, Del Genio AD, Hack JJ, Loeb NG, Lohmann U, Minnis P, Musat I, Pincus R, Stier P, Suarez MJ, Webb MJ, Wu JB, Xie SC, Yao M-S, Zhang JH (2005) Comparing clouds and their seasonal variations in 10 atmospheric general circulation models with satellite measurements. J Geophys Res 110(D15):S02. doi:10.1029/2004JD005021 Google Scholar