Journal article
Understanding the mechanisms for tropical surface impacts of the quasi‐biennial oscillation (QBO)
- Abstract:
- The impact of the quasi-biennial oscillation (QBO) on tropical convection and precipitation is investigated through nudging experiments using the UK Met Office Hadley Center Unified Model. The model control simulations show robust links between the internally generated QBO and tropical precipitation and circulation. The model zonal wind in the tropical stratosphere was nudged above 90 hPa in atmosphere-only and coupled ocean-atmosphere configurations. The convection and precipitation in the atmosphere-only simulations do not differ between the experiments with and without nudging, which may indicate that SST-convection coupling is needed for any QBO influence on the tropical lower troposphere and surface. In the coupled experiments, the precipitation and sea-surface temperature relationships with the QBO phase disappear when nudging is applied. Imposing a realistic QBO-driven static stability anomaly in the upper-troposphere lower-stratosphere is not sufficient to simulate tropical surface impacts. The nudging reduced the influence of the lower troposphere on the upper branch of the Walker circulation, irrespective of the QBO, indicating that the upper tropospheric zonal circulation has been decoupled from the surface by the nudging. These results suggest that grid-point nudging mutes relevant feedback processes occurring at the tropopause level, including high cloud radiative effects and wave mean flow interactions, which may play a key role in stratospheric-tropospheric coupling.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Version of record, pdf, 6.4MB, Terms of use)
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- Publisher copy:
- 10.1029/2023jd038474
Authors
- Publisher:
- Wiley
- Journal:
- Journal of Geophysical Research: Atmospheres More from this journal
- Volume:
- 128
- Issue:
- 15
- Article number:
- e2023JD038474
- Publication date:
- 2023-07-29
- Acceptance date:
- 2023-06-16
- DOI:
- EISSN:
-
2169-8996
- ISSN:
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2169-897X
- Language:
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English
- Keywords:
- Pubs id:
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1489543
- Local pid:
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pubs:1489543
- Deposit date:
-
2023-08-02
Terms of use
- Copyright holder:
- García-Franco et al.
- Copyright date:
- 2023
- Rights statement:
- © 2023. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
- Licence:
- CC Attribution (CC BY)
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