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| Titel |
The impact of midlatitude stationary waves on the Hadley cell and ENSO |
| VerfasserIn |
R. Caballero, B. T. Anderson |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250026654
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| Zusammenfassung |
| Stationary planetary waves are excited in the midlatitudes, propagate equatorward and are
absorbed in the subtropics. The impact these waves have on the tropical climate has yet to be
fully unraveled. One strand of research (Caballero 2007) has shown that interannual
variability of stationary wave Reynolds stresses is well correlated with interannual
variability in Hadley cell strength, a connection which can be physically understood
by considering the zonal-mean momentum balance in the subtropics. A separate
line of research (Vimont et al. 2003, Anderson 2004) has shown that changes in
midlatitude planetary waves local to the Pacific strongly affect ENSO variability.
Here, we show that the two phenomena are in fact closely connected. Interannual
variability of wave activity flux convergence in the subtropical Pacific strongly affects
the local Hadley cell, including subtropical subsidence and surface wind stresses,
which in turn can initiate the onset of ENSO events. As a result, a winter with an
anomalously strong Hadley cell tends to be followed a year later by an El Niño event. |
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