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| Titel |
Explaining a perpetual Pliocene El Niño with enhanced organized convective activity |
| VerfasserIn |
Nathan Arnold, Eli Tziperman |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250037308
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| Zusammenfassung |
| The early Pliocene (3-5Ma) climate is considered a potential analogue for the future because
of its near-modern continental configuration, estimated temperatures  3oC warmer than
present, and CO2 levels of 300-500ppm, essentially those expected in the near future. Proxy
data for sea surface temperatures suggest that the area of the modern cold tongue was much
warmer during this period, similar to a modern El Niño event, and other proxy data have been
interpreted to suggest an El Niño-like signature on the overall Pliocene climate. In this work
we test an explanation for these anomalies based on a perpetual or more frequent El
Niño resulting from a sustained reduction in the mean equatorial surface easterlies.
Such a reduction is hypothesized to result from enhanced convective activity over
the Pacific in the warmer Pliocene atmosphere. This convective activity acts as a
stochastic source of atmospheric Rossby waves, which produce an equatorward
convergence of westerly momentum, weakening the surface easterlies. Results are
presented from a hierarchy of models examining each element of the hypothesis. |
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