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| Titel |
Net influence of an internally generated quasi-biennial oscillation on modelled stratospheric climate and chemistry |
| VerfasserIn |
M. M. Hurwitz, L. D. Oman, P. A. Newman, I.-S. Song |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 24 ; Nr. 13, no. 24 (2013-12-17), S.12187-12197 |
| Datensatznummer |
250085883
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| Publikation (Nr.) |
 copernicus.org/acp-13-12187-2013.pdf |
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| Zusammenfassung |
| A Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM)
simulation with strong tropical non-orographic gravity wave drag (GWD) is
compared to an otherwise identical simulation with near-zero tropical
non-orographic GWD. The GEOSCCM generates a quasi-biennial oscillation
(QBO) zonal wind signal in response to a tropical peak in GWD that resembles
the zonal and climatological mean precipitation field. The modelled QBO has
a frequency and amplitude that closely resembles observations. As expected,
the modelled QBO improves the simulation of tropical zonal winds and
enhances tropical and subtropical stratospheric variability. Also,
inclusion of the QBO slows the meridional overturning circulation, resulting
in a generally older stratospheric mean age of air. Slowing of the
overturning circulation, changes in stratospheric temperature and enhanced
subtropical mixing all affect the annual mean distributions of ozone,
methane and nitrous oxide. Furthermore, the modelled QBO enhances polar
stratospheric variability in winter. Because tropical zonal winds are
easterly in the simulation without a QBO, there is a relative increase in
tropical zonal winds in the simulation with a QBO. Extratropical
differences between the simulations with and without a QBO thus reflect the
westerly shift in tropical zonal winds: a relative strengthening of the
polar stratospheric jet, polar stratospheric cooling and a weak reduction in
Arctic lower stratospheric ozone. |
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