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| Titel |
ENSO and IOD teleconnections for African ecosystems: evidence of destructive interference between climate oscillations |
| VerfasserIn |
C. A. Williams, N. P. Hanan |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 8, no. 1 ; Nr. 8, no. 1 (2011-01-04), S.27-40 |
| Datensatznummer |
250005343
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| Publikation (Nr.) |
 copernicus.org/bg-8-27-2011.pdf |
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| Zusammenfassung |
| Rainfall and vegetation across Africa are known to resonate with the coupled
ocean-atmosphere phenomena of El Niño Southern Oscillation (ENSO) and
the Indian Ocean Dipole (IOD). However, the regional-scale implications of
sea surface temperature variability for Africa's photosyntheis have received
little focused attention, particularly in the case of IOD. Furthermore,
studies exploring the interactive effects of ENSO and IOD when coincident
are lacking. This analysis uses remotely sensed vegetation change plus a
land surface model driven with observed meteorology to investigate how
rainfall, vegetation, and photosynthesis across Africa respond to these
climate oscillations. In addition to the relatively well-known ENSO forcing,
the IOD induces large departures of photosynthesis across much of Africa
associated with anomalies in rainfall and vegetation greenness. More
importantly, sizeable independent effects can be suppressed or even reversed
by destructive interferences during periods of simultaneous ENSO and IOD
activity. For example, effects of positive IOD on southeastern Africa tended
to dominate those of El Niño during their coincidence spanning
1997–1998, with sign reversal of El Niño's typically strong suppression
of photosynthesis in this region. These findings call into question past
analyses examining teleconnections to ENSO or IOD in isolation, and indicate
the need to consider their simultaneous states when examining influences on
hydroclimatic and ecological conditions across Africa. |
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