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Titre du document / Document title

Enhanced albedo feedback in North Africa from possible combined vegetation and soil-formation processes

Auteur(s) / Author(s)

KNORR Wolfgang (1) ; SCHNITZLER Karl-Georg (2) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, BS8 IRJ Bristol, ROYAUME-UNI
(2) Max-Planck-Institut für Meteorologie, Bundesstr. 53, 20146 Hamburg, ALLEMAGNE

Résumé / Abstract

It has long been recognized that albedo related vegetation feedbacks amplify climate variability in North Africa. Recent studies have revealed that areas of very high albedo associated with certain desert soil types contribute to the current dry climate of the region. We construct three scenarios of North African albedo, one based on satellite measurements, one where the highest albedo resembles that of soils in the desert transition zones, and one based on a vegetation map for the green Sahara state of the middle Holocene, ca. 6,000 years ago. Using a series of climate model simulations, we find that the additional amplitude of albedo change from the middle Holocene to the present caused by the very bright desert soils enhances the magnitude of the June-to-August precipitation change in the region of the present Sahara from 0.6 to 1.0 mm/day on average. We also find that albedo change has a larger effect on regional precipitation than changes in either the Earth's orbit or sea surface temperatures between 6,000 years ago and today. Simulated precipitation agrees rather well with present observations and mid Holocene reconstructions. Our results suggest that there may exist an important climate feedback from soil formation processes that has so far not been recognized.

Revue / Journal Title

Climate dynamics    ISSN  0930-7575   CODEN CLDYEM 

Source / Source

2006, vol. 26, no1, pp. 55-63 [9 page(s) (article)] (40 ref.)

Langue / Language

Anglais

Editeur / Publisher

Springer, Heidelberg, ALLEMAGNE  (1986) (Revue)

Mots-clés anglais / English Keywords

Africa

;

Phanerozoic

;

Cenozoic

;

Quaternary

;

upper Quaternary

;

Dynamical climatology

;

Sahara

;

North Africa

;

Holocene

;

paleoclimate

;

Climate models

;

General circulation models

;

digital simulation

;

feedback

;

Effect on climate

;

Regional scope

;

atmospheric precipitation

;

deserts

;

arid environment

;

Plant cover

;

albedo

;

Vegetation effect

;

Air biosphere interaction

;

Climate variation

;

Mots-clés français / French Keywords

Afrique

;

Phanérozoïque

;

Cénozoïque

;

Quaternaire

;

Quaternaire sup

;

Climatologie dynamique

;

Sahara

;

Afrique du Nord

;

Holocène

;

Paléoclimat

;

Modèle climat

;

Modèle circulation générale

;

Simulation numérique

;

Rétroaction

;

Effet sur climat

;

Echelon régional

;

Précipitation atmosphérique

;

Désert

;

Milieu aride

;

Couvert végétal

;

Albedo

;

Action végétation

;

Interaction air biosphère

;

Variation climat

;

Mots-clés espagnols / Spanish Keywords

Africa

;

Fanerozoico

;

Cenozoico

;

Cuaternario

;

Cuaternario sup

;

Climatología dinámica

;

Sahara

;

Africa del norte

;

Holoceno

;

Paleoclima

;

Simulación numérica

;

Efecto sobre clima

;

Escala regional

;

Precipitación atmosférica

;

Desierto

;

Medio árido

;

Cubierta vegetal

;

Albedo

;

Acción vegetación

;

Interacción aire biosfera

;

Variación clima

;

Localisation / Location

INIST-CNRS, Cote INIST : 21148, 35400013498119.0040

Nº notice refdoc (ud4) : 17397668



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