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Mechanisms in regulating the quasi-biennial oscillation in E3SM version 2
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  • Yuanpu Li,
  • Chih-Chieh Chen,
  • Jadwiga H. Richter,
  • Julio T. Bacmeister,
  • James J Benedict
Yuanpu Li
National Center for Atmospheric Research

Corresponding Author:[email protected]

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Chih-Chieh Chen
NCAR CGD
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Jadwiga H. Richter
National Center for Atmospheric Research (UCAR)
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Julio T. Bacmeister
National Center for Atmospheric Research (UCAR)
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James J Benedict
Los Alamos National Lab
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Abstract

The simulated quasi-biennial oscillation (QBO) in the Energy Exascale Earth System Model version 2 (E3SMv2) is characterized by a shorter period and stronger amplitude compared with its predecessor E3SMv1. This is primarily attributed to updates to the deep convection parameterization which makes convection more intense but less frequent while leaving the time-mean convective heating tendency almost unchanged. Amplitudes of momentum fluxes associated with parameterized gravity waves, which are determined by the square of convective heating tendency, are consequently intensified. In addition, stronger planetary waves, another contributor to the QBO driving, are simulated in E3SMv2 in part due to tropospheric processes. Furthermore, there is evidence that planetary wave generation is present in the stratosphere due to dissipation of amplified parameterized gravity waves. These factors are found to be responsible for the stronger and faster QBO simulated in E3SMv2.
10 Jul 2024Submitted to ESS Open Archive
14 Jul 2024Published in ESS Open Archive