The impact of Sahara desertification on Arctic cooling during the Holocene

Autor(en)
F. J. Davies, H. Renssen, M. Blaschek, F. Muschitiello
Abstrakt

Since the start of the Holocene, temperatures in the Arctic have steadily declined. This has been accredited to the orbitally forced decrease in summer insolation reconstructed over the same period. However, here we present climate modelling results from an Earth model of intermediate complexity (EMIC) that indicate that 17-40% of the cooling in the Arctic, over the period 9-0 ka, was a direct result of the desertification that occurred in the Sahara after the termination of the African Humid Period. We have performed a suite of sensitivity experiments to analyse the impact of different combinations of forcings, including various vegetation covers in the Sahara. Our simulations suggest that over the course of the Holocene, a strong increase in surface albedo in the Sahara as a result of desertification led to a regional increase in surface pressure, a weakening of the trade winds, the westerlies and the polar easterlies, which in turn reduced the meridional heat transported by the atmosphere to the Arctic. We conclude that during interglacials, the climate of the Northern Hemisphere is sensitive to changes in Sahara vegetation type.

Organisation(en)
Institut für Meteorologie und Geophysik
Externe Organisation(en)
Vrije Universiteit Amsterdam, Stockholm University
Journal
Climate of the Past
Band
11
Seiten
571-586
Anzahl der Seiten
16
ISSN
1814-9324
DOI
https://doi.org/10.5194/cp-11-571-2015
Publikationsdatum
2015
Peer-reviewed
Ja
ÖFOS 2012
105204 Klimatologie, 105205 Klimawandel, 105907 Polarforschung
Schlagwörter
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/the-impact-of-sahara-desertification-on-arctic-cooling-during-the-holocene(91889def-6ae8-490c-8545-25cb85f25c9a).html