Interpretation of Snow-Climate Feedback as Produced by 17 General Circulation Models

¹ Institute for Terrestrial and Planetary Atmospheres, State University of New York, Stony Brook, NY 11794
² Lawrence Livermore National Laboratory, Livermore, CA 94550
³ Canadian Climate Centre, Downsview, Ontario, Canada M3H 574
⁴ Laboratoire de Météorologie Dynamique, 24 Rue Lhomond, 75231 Paris Cédex 05, France
⁵ Bureau of Meteorology Research Centre, GPO Box 1289K, Melbourne, 3001 Victoria, Australia
⁶ Colorado State University, Fort Collins, CO 80523
⁷ National Aeronautics and Space Administration (NASA) Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025
⁸ Department of Numerical Mathematics, USSR Academy of Sciences, 29 Ryleeva Street, Moscow 119034, USSR
⁹ Hadley Centre for Climate Prediction and Research, Meteorological Office, Bracknell, Berkshire RG12 2SZ, England
¹⁰ Max Planck Institute for Meteorology, Bundestrasse 55, D2000, Hamburg 13, Federal Republic of Germany
¹¹ State University of New York, Albany, NY 12205
¹² Direction de la Météorologie Nationale, Centre National de Recherches Metallurgiques (CNRM), 42 Avenue Coriolis, 31057 Toulouse Cédex, France
¹³ Voeikov Main Geophysical Observatory, 7 Karbisheva, Leningrad 194018, USSR
¹⁴ European Centre for Medium-Range Weather Forecasts, Reading, Berkshire RG2 9AX, England
¹⁵ Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093
¹⁶ University of Reading, Reading, Berkshire RG6 2AU, England
¹⁷ National Center for Atmospheric Research, Boulder, CO 80307
¹⁸ Princeton University, National Oceanic and Atmospheric Administration-Geophysical Fluid Dynamics Laboratory, Post Office Box 308, Princeton, NJ 08540
¹⁹ Meteorological Research Institute, 1-1, Nagamine, Tsukuba, Ibaraki-ken 305, Japan

Snow feedback is expected to amplify global warming caused by increasing concentrations of atmospheric greenhouse gases. The conventional explanation is that a warmer Earth will have less snow cover, resulting in a darker planet that absorbs more solar radiation. An intercomparison of 17 general circulation models, for which perturbations of sea surface temperature were used as a surrogate climate change, suggests that this explanation is overly simplistic. The results instead indicate that additional amplification or moderation may be caused both by cloud interactions and longwave radiation. One measure of this net effect of snow feedback was found to differ markedly among the 17 climate models, ranging from weak negative feedback in some models to strong positive feedback in others.