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A novel gravity wave transport parametrization for global chemistry climate models: description and validation
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  • Maria Vittoria Guarino,
  • Chester S. Gardner,
  • Wuhu Feng,
  • Bernd Funke,
  • Maya García-Comas,
  • Manuel Lopez Puertas,
  • Marcin M Kupilas,
  • Daniel R Marsh,
  • John Maurice Campbell Plane
Maria Vittoria Guarino
International Centre for Theoretical Physics

Corresponding Author:[email protected]

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Chester S. Gardner
University of Illinois at Urbana Champaign
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Wuhu Feng
National Centre for Atmospheric Science
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Bernd Funke
Instituto de Astrofísica de Andalucía, CSIC
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Maya García-Comas
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Manuel Lopez Puertas
Instituto de Astrofisica de Andalucia, CSIC
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Marcin M Kupilas
University of Leeds
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Daniel R Marsh
University of Leeds
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John Maurice Campbell Plane
University of Leeds
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The gravity wave drag parametrization of the Whole Atmosphere Community Climate Model (WACCM) has been modified to include the wave-driven atmospheric vertical mixing caused by propagating, non-breaking, gravity waves. The strength of this atmospheric mixing is represented in the model via the "effective wave diffusivity" coefficient K_wave. Using K_wave, a new total dynamical diffusivity K_Dyn is defined. K_Dyn represents the vertical mixing of the atmosphere by both breaking (dissipating) and vertically propagating (non-dissipating) gravity waves. Here we show that, when the new diffusivity is used, the downward fluxes of Fe and Na between 80 and 100 km largely increase. Larger meteoric ablation injection rates of these metals (within a factor 2 of measurements) can now be used in WACCM, which produce Na and Fe layers in good agreement with lidar observations. Mesospheric CO2 is also significantly impacted, with the largest CO2 concentration increase occurring between 80-90 km, where model-observations agreement improves. However, in regions where the model overestimates CO2 concentration, the new parametrization exacerbates the model bias. The mesospheric cooling simulated by the new parametrization, while needed, is currently too strong almost everywhere. The summer mesopause in both hemispheres becomes too cold by about 30K compared to observations, but it shifts upward, partially correcting the WACCM low summer mesopause. Our results highlight the far-reaching implications and the necessity of representing vertically propagating gravity waves in climate models. This novel method of modelling gravity waves contributes to growing evidence that it is time to move away from dissipative-only gravity wave parametrizations.
07 Apr 2024Submitted to ESS Open Archive
08 Apr 2024Published in ESS Open Archive