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| Titel |
A further assessment of vegetation feedback on decadal Sahel rainfall variability |
| VerfasserIn |
F. Kucharski, N. Zeng, E. Kalnay |
| 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 |
250060630
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| Zusammenfassung |
| In this paper the vegetation feedback on decadal Sahelian
rainfall is analyzed using a set of ensembles of Atmospheric
General Circulation Model/dynamic vegetation simulations.
In the control experiment, where the full vegetation feedback
is included, the ensemble is consistent with the observed
decadal rainfall variability, with a forced component estimated
from the ensemble mean to be about 60% of the observed variability.
In a sensitivity experiment where climatological vegetation cover
and albedo are prescribed from the control experiment, the ensemble
of simulations is not consistent with the observations because
of strongly reduced amplitude of decadal rainfall variability,
and the forced component drops to 40% of the observed variability.
The decadal rainfall variability is driven by sea surface
temperature (SST) forcing, but enhanced by land-surface feedbacks.
Both, local evaporation and moisture flux convergence changes
are important for the total rainfall response. Also the internal
decadal variability (not SST-forced) is much stronger in the
control experiment compared with the one where vegetation cover
and albedo are prescribed. It is further shown that this positive
vegetation feedback is physically related to the albedo feedback,
supporting the Charney hypothesis. |
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