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The GFDL Global Atmospheric Chemistry-Climate Model AM4.1: Model Description and Simulation Characteristics
  • +13
  • Larry Wayne Horowitz,
  • Vaishali Naik,
  • Fabien Paulot,
  • Paul A Ginoux,
  • John P Dunne,
  • Jingqiu Mao,
  • Jordan Schnell,
  • Xi Chen,
  • Jian He,
  • Jasmin G John,
  • Meiyun Lin,
  • Pu Lin,
  • Sergey Malyshev,
  • David Paynter,
  • Elena Shevliakova,
  • Ming Zhao
Larry Wayne Horowitz
NOAA/GFDL

Corresponding Author:[email protected]

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Vaishali Naik
NOAA/GFDL
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Fabien Paulot
NOAA/GFDL
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Paul A Ginoux
NOAA/GFDL
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John P Dunne
NOAA/GFDL
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Jingqiu Mao
University of Alaska
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Jordan Schnell
Northwestern University
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Xi Chen
Princeton University
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Jian He
Princeton University
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Jasmin G John
NOAA/GFDL
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Meiyun Lin
Princeton University
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Pu Lin
GFDL/UCAR
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Sergey Malyshev
NOAA/GFDL
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David Paynter
NOAA/GFDL
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Elena Shevliakova
NOAA/GFDL
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Ming Zhao
NOAA/GFDL
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Abstract

We describe the baseline model configuration and simulation characteristics of GFDL’s Atmosphere Model version 4.1 (AM4.1), which builds on developments at GFDL over 2013–2018 for coupled carbon-chemistry-climate simulation as part of the sixth phase of the Coupled Model Intercomparison Project. In contrast with GFDL’s AM4.0 development effort, which focused on physical and aerosol interactions and which is used as the atmospheric component of CM4.0, AM4.1 focuses on comprehensiveness of Earth system interactions. Key features of this model include doubled horizontal resolution of the atmosphere (~200 km to ~100 km) with revised dynamics and physics from GFDL’s previous-generation AM3 atmospheric chemistry-climate model. AM4.1 features improved representation of atmospheric chemical composition, including aerosol and aerosol precursor emissions, key land-atmosphere interactions, comprehensive land-atmosphere-ocean cycling of dust and iron, and interactive ocean-atmosphere cycling of reactive nitrogen. AM4.1 provides vast improvements in fidelity over AM3, captures most of AM4.0’s baseline simulations characteristics and notably improves on AM4.0 in the representation of aerosols over the Southern Ocean, India, and China—even with its interactive chemistry representation—and in its manifestation of sudden stratospheric warmings in the coldest months. Distributions of reactive nitrogen and sulfur species, carbon monoxide, and ozone are all substantially improved over AM3. Fidelity concerns include degradation of upper atmosphere equatorial winds and of aerosols in some regions.
Oct 2020Published in Journal of Advances in Modeling Earth Systems volume 12 issue 10. 10.1029/2019MS002032