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Observational validation of parameterized gravity waves from tropical convection in the Whole Atmosphere Community Climate Model (WACCM)
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  • M. Joan Alexander,
  • Chuntao Liu,
  • Julio T. Bacmeister,
  • Martina Bramberger,
  • Albert Hertzog,
  • Jadwiga H. Richter
M. Joan Alexander
NorthWest Research Associates, CoRA Office

Corresponding Author:[email protected]

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Chuntao Liu
Texas A&M Corpus Christi
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Julio T. Bacmeister
National Center for Atmospheric Research (UCAR)
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Martina Bramberger
NWRA
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Albert Hertzog
Laboratoire de météorologie dynamique
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Jadwiga H. Richter
National Center for Atmospheric Research (UCAR)
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Abstract

Tropical gravity waves that are generated by convection are generally too small in scale and too high in frequency to be resolved in global climate models, yet their drag forces drive the important global-scale quasi-biennial oscillation (QBO) in the lower stratosphere, and models rely on parameterizations of gravity wave drag to simulate the QBO. We compare detailed properties of tropical parameterized gravity waves in the Whole Atmosphere Community Climate Model Version 6 (WACCM6) with gravity waves observed by long-duration super-pressure balloons, and also compare properties of parameterized convective latent heating with satellite data. Similarities and differences suggest that the WACCM6 parameterizations are excellent tools for representing tropical gravity waves, but the results also suggest detailed changes to the gravity wave parameterization tuning parameter assumptions that would bring the parameterized waves into much better agreement with observations. While WACCM6 currently includes only non-stationary gravity waves from convection, addition of the component that is stationary relative to convective rain cells is likely to improve the simulation of the QBO in the model. The suggested changes have the potential to alleviate common biases in simulated QBO circulations in models.
16 Apr 2021Published in Journal of Geophysical Research: Atmospheres volume 126 issue 7. 10.1029/2020JD033954