EarthRef.org Reference Database (ERR)
Development and Maintenance by the EarthRef.org Database Team

Detailed Reference Information
Peyron et al. 2006
Peyron, O., Jolly, D., Braconnot, P., Bonnefille, R., Guiot, J., Wirrmann, D. and Chalié, F. (2006). Quantitative reconstructions of annual rainfall in Africa 6000 years ago: Model-data comparison. Journal of Geophysical Research 111: doi: 10.1029/2006JD007396. issn: 0148-0227.

This paper provides the first set of quantitative reconstructions of annual precipitation for mid-Holocene Africa, based on pollen data. The estimates of precipitation are based on 85 pollen sites 14C dated at 6000 ¿ 500 years B.P and distributed over the whole of Africa. To improve the reliability of the pollen-based climate reconstruction, two methods are used: the "modern analogues technique" (MAT) and the "plant functional types" (PFT) methods. We then conduct a model-data comparison for five distinct regions, allowing an evaluation of model outputs (the Sahara-Sahel, the eastern Sahara, western equatorial Africa, East Africa, and Madagascar). The pollen-inferred reconstructions are compared with 21 mid-Holocene simulations yielded by Atmospheric General Circulation Models (AGCMs), and coupled ocean-atmosphere-vegetation models (OAVGCMs). The large-scale feature of the hydrological changes is shown to be well captured by most of the models. Data show that during the mid-Holocene, the Sahara was considerably wetter than today (+200 to +700 mm/yr). The results reinforce the conclusion that the AGCMs significantly underestimate this precipitation increase in the Sahara whereas the OAVGCM simulations are in accordance with the data. Our results show that vegetation and ocean feedbacks do not have a strong impact in the intertropical zone and that models fail to properly reproduce the climatic conditions in East Africa and Madagascar. The model-data comparison also suggests that the lengthening of the dry season during boreal winter in the west equatorial region is a robust feature although the pollen-based reconstruction shows no change or only slight drying there.

BACKGROUND DATA FILES

Abstract

Keywords
Biogeosciences, Paleoclimatology and paleoceanography (3344, 4900), Global Change, Global climate models (3337, 4928), Biogeosciences, Climate dynamics, Global Change, Abrupt/rapid climate change (4901, 8408), Geographic Location, Africa
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
2000 Florida Avenue N.W.
Washington, D.C. 20009-1277
USA
1-202-462-6900
1-202-328-0566
service@agu.org
Click to clear formClick to return to previous pageClick to submit