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On the effect of historical SST patterns on radiative feedback
  • +17
  • Timothy Andrews,
  • Jonathan M. Gregory,
  • Yue Dong,
  • Kyle Armour,
  • David Paynter,
  • Pu Lin,
  • Angshuman Modak,
  • Thorsten Mauritsen,
  • Jason Cole,
  • Brian Medeiros,
  • James Benedict,
  • Hervé Douville,
  • Romain Roehrig,
  • Tsuyoshi Koshiro,
  • Hideaki Kawai,
  • Tomoo Ogura,
  • Jean-Louis Dufresne,
  • Alejandro Bodas-Salcedo,
  • Richard Philip Allan,
  • Chunlei Liu
Timothy Andrews
Met Office, Met Office, Met Office

Corresponding Author:[email protected]

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Jonathan M. Gregory
University of Reading, University of Reading, University of Reading
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Yue Dong
University of Washington, University of Washington, University of Washington
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Kyle Armour
University of Washington, University of Washington, University of Washington
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David Paynter
GFDL/NOAA, GFDL/NOAA, GFDL/NOAA
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Pu Lin
Princeton University, Princeton University, Princeton University
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Angshuman Modak
Department of Meteorology, Stockholm University, Department of Meteorology, Stockholm University, Department of Meteorology, Stockholm University
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Thorsten Mauritsen
Department of Meteorology, Stockholm University, Department of Meteorology, Stockholm University, Department of Meteorology, Stockholm University
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Jason Cole
Environment and Climate Change Canada, Environment and Climate Change Canada, Environment and Climate Change Canada
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Brian Medeiros
National Center for Atmospheric Research, National Center for Atmospheric Research, National Center for Atmospheric Research
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James Benedict
Los Alamos National Laboratory, Los Alamos National Laboratory, Los Alamos National Laboratory
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Hervé Douville
Météo-France, Météo-France, Météo-France
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Romain Roehrig
CNRM, Université de Toulouse, Météo-France, CNRS, CNRM, Université de Toulouse, Météo-France, CNRS, CNRM, Université de Toulouse, Météo-France, CNRS
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Tsuyoshi Koshiro
Meteorological Research Institute, Meteorological Research Institute, Meteorological Research Institute
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Hideaki Kawai
Meteorological Research Institute, Meteorological Research Institute, Meteorological Research Institute
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Tomoo Ogura
National Institute for Environmental Studies, National Institute for Environmental Studies, National Institute for Environmental Studies
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Jean-Louis Dufresne
LMD/IPSL, LMD/IPSL, LMD/IPSL
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Alejandro Bodas-Salcedo
Met Office Hadley Centre, Met Office Hadley Centre, Met Office Hadley Centre
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Richard Philip Allan
Reading University, Reading University, Reading University
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Chunlei Liu
Guangdong Ocean University, Guangdong Ocean University, Guangdong Ocean University
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Abstract

We investigate the dependence of radiative feedback on the pattern of sea-surface temperature (SST) change in fourteen Atmospheric General Circulation Models (AGCMs) forced with observed variations in SST and sea-ice over the historical record from 1871 to near-present. We find that over 1871-1980, the Earth warmed with feedbacks largely consistent and strongly correlated with long-term climate sensitivity feedbacks (diagnosed from corresponding atmosphere-ocean GCM abrupt-4xCO2 simulations). Post 1980 however, the Earth warmed with unusual trends in tropical Pacific SSTs (enhanced warming in the west, cooling in the east) that drove climate feedback to be uncorrelated with – and indicating much lower climate sensitivity than – that expected for long-term CO2 increase. We show that these conclusions are not strongly dependent on the AMIP II SST dataset used to force the AGCMs, though the magnitude of feedback post 1980 is generally smaller in eight AGCMs forced with alternative HadISST1 SST boundary conditions. We quantify a ‘pattern effect’ (defined as the difference between historical and long-term CO2 feedback) equal to 0.44 ± 0.47 [5-95%] W m-2 K-1 for the time-period 1871-2010, which increases by 0.05 ± 0.04 W m-2 K-1 if calculated over 1871-2014. Assessed changes in the Earth’s historical energy budget are in agreement with the AGCM feedback estimates. Furthermore satellite observations of changes in top-of-atmosphere radiative fluxes since 1985 suggest that the pattern effect was particularly strong over recent decades, though this may be waning post 2014 due to a warming of the eastern Pacific.