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The Green’s Function Model Intercomparison Project (GFMIP) Protocol
  • +10
  • Jonah Bloch-Johnson,
  • Maria A.A. Rugenstein,
  • Marc J. Alessi,
  • Cristian Proistosescu,
  • Ming Zhao,
  • Bosong Zhang,
  • Andrew I.L. Williams,
  • Jonathan M. Gregory,
  • Jason Cole,
  • Yue Dong,
  • Margaret L Duffy,
  • Sarah M. Kang,
  • Chen Zhou
Jonah Bloch-Johnson
University of Reading

Corresponding Author:[email protected]

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Maria A.A. Rugenstein
Colorado State University
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Marc J. Alessi
Colorado State University
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Cristian Proistosescu
University of Washington
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Ming Zhao
GFDL/NOAA
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Bosong Zhang
University of Miami
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Andrew I.L. Williams
University of Oxford
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Jonathan M. Gregory
University of Reading
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Jason Cole
Environment and Climate Change Canada
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Yue Dong
Columbia University
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Margaret L Duffy
National Center for Atmospheric Research
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Sarah M. Kang
Ulsan National Institute of Science and Technology
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Chen Zhou
Nanjing University
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Abstract

The atmospheric Green’s function method is a technique for modeling the response of the atmosphere to changes in the spatial field of surface temperature. While early studies applied this method to changes in atmospheric circulation, it has also become an important tool to understand changes in radiative feedbacks due to evolving patterns of warming, a phenomenon called the "pattern effect." To better study this method, this paper presents a protocol for creating atmospheric Green’s functions to serve as the basis for a model intercomparison project, GFMIP. The protocol has been developed using a series of sensitivity tests performed with the HadAM3 atmosphere-only general circulation model, along with existing and new simulations from other models. Our preliminary results have uncovered nonlinearities in the response of the atmosphere to surface temperature changes, including an asymmetrical response to warming vs. cooling patch perturbations, and a change in the dependence of the response on the magnitude and size of the patches. These nonlinearities suggest that the pattern effect may depend on the heterogeneity of warming as well as its location. These experiments have also revealed tradeoffs in experimental design between patch size, perturbation strength, and the length of control and patch simulations. The protocol chosen on the basis of these experiments balances scientific utility with the simulation time and setup required by the Green’s function approach. Running these simulations will further our understanding of many aspects of atmospheric response, from the pattern effect and radiative feedbacks to changes in circulation, cloudiness, and precipitation.
10 Mar 2023Submitted to ESS Open Archive
13 Mar 2023Published in ESS Open Archive