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| Titel |
Differences in the wave guide characteristics of the jet stream in positive and negative phases of the NAO |
| VerfasserIn |
I. Manola, F. Selten |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250059227
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| Zusammenfassung |
| Jet streams are known to act as waveguides. In this study we compare the structure of the
Northern Hemisphere
winter jet streams during positive and negative phases of the NAO. Differences are found in
the strength, width and zonal asymmetries of these jet structures. Calculations of Rossby
wave dispersion using the barotropic vorticity
equation in the sphere with these jets as basic states show marked differences in the response
to low latitude
vorticity sources. Meridional wind anomalies are examined as signatures of zonally extended
waves trapped in the
jet stream wave guide. We find that the observed zonal waves in the North Atlantic region are
well reproduced
by the barotropic calculations during the negative NAO phase only. We hypothesize that the
jets during positive
NAO phase are more unstable and therefore cannot act as barotropic wave guides. |
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