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Titel |
North African vegetation–precipitation feedback in early and mid-Holocene climate simulations with CCSM3-DGVM |
VerfasserIn |
R. Rachmayani, M. Prange, M. Schulz |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1814-9324
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Digitales Dokument |
URL |
Erschienen |
In: Climate of the Past ; 11, no. 2 ; Nr. 11, no. 2 (2015-02-06), S.175-185 |
Datensatznummer |
250117161
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Publikation (Nr.) |
copernicus.org/cp-11-175-2015.pdf |
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Zusammenfassung |
The present study analyses the sign, strength, and working mechanism of the
vegetation–precipitation feedback over North Africa in middle (6 ka BP) and
early Holocene (9 ka BP) simulations using the comprehensive coupled
climate–vegetation model CCSM3-DGVM (Community Climate System
Model version 3 and a dynamic global vegetation model). The coupled model simulates enhanced
summer rainfall and a northward migration of the West African monsoon trough
along with an expansion of the vegetation cover for the early and middle
Holocene compared to the pre-industrial period. It is shown that dynamic vegetation
enhances the orbitally triggered summer precipitation anomaly by
approximately 20% in the Sahara–Sahel region
(10–25° N, 20° W–30° E) in both the early
and mid-Holocene experiments compared to their fixed-vegetation counterparts.
The primary vegetation–rainfall feedback identified here operates through
surface latent heat flux anomalies by canopy evaporation and transpiration
and their effect on the mid-tropospheric African easterly jet, whereas the
effects of vegetation changes on surface albedo and local water recycling
play a negligible role. Even though CCSM3-DGVM simulates a positive
vegetation–precipitation feedback in the North African region, this feedback
is not strong enough to produce multiple equilibrium climate-ecosystem states
on a regional scale. |
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