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| Titel |
Momentum forcing of the quasi-biennial oscillation by equatorial waves in recent reanalyses |
| VerfasserIn |
Y.-H. Kim, H.-Y. Chun |
| 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 ; 15, no. 12 ; Nr. 15, no. 12 (2015-06-16), S.6577-6587 |
| Datensatznummer |
250119827
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| Publikation (Nr.) |
 copernicus.org/acp-15-6577-2015.pdf |
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| Zusammenfassung |
| The momentum forcing of the QBO (quasi-biennial oscillation) by equatorial waves is estimated
using recent reanalyses. Based on the estimation using the
conventional pressure-level data sets, the forcing by the Kelvin
waves (3–9 m s−1 month−1) dominates the net
forcing by all equatorial wave modes (3–11 m s−1 month−1)
in the easterly-to-westerly transition phase at 30 hPa.
In the opposite phase,
the net forcing by equatorial wave modes is small
(1–5 m s−1 month−1). By comparing the results
with those from the native model-level data set of the
ERA-Interim reanalysis, it is suggested that the use of
conventional-level data causes the Kelvin wave forcing to be
underestimated by 2–4 m s−1 month−1. The
momentum forcing by mesoscale gravity waves, which are
unresolved in the reanalyses, is deduced from the residual of
the zonal wind tendency equation. In the easterly-to-westerly
transition phase at 30 hPa, the mesoscale gravity wave forcing is
found to be smaller than the resolved wave forcing, whereas the
gravity wave forcing dominates over the resolved wave forcing in
the opposite phase. Finally, we discuss the uncertainties in
the wave forcing estimates using the reanalyses. |
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