Influence of the North Atlantic subpolar gyre circulation on the 4.2 ka BP event

The 4.2 ka BP event, spanning from ca 4200 to 3900 cal BP, has been documented in numerous archaeological data and continental archives across the Northern Hemisphere as an abrupt shift to dry and cold climate. However, data on synchronous ocean circulation changes are notably lacking, thus preventi...

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Bibliographic Details
Published in:Climate of the Past
Main Authors: B. Jalali, M.-A. Sicre, J. Azuara, V. Pellichero, N. Combourieu-Nebout
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2019
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Online Access:https://doi.org/10.5194/cp-15-701-2019
https://doaj.org/article/39ae5727d0e6404a8e74857e41eeae40
Description
Summary:The 4.2 ka BP event, spanning from ca 4200 to 3900 cal BP, has been documented in numerous archaeological data and continental archives across the Northern Hemisphere as an abrupt shift to dry and cold climate. However, data on synchronous ocean circulation changes are notably lacking, thus preventing us from getting a full insight into the physical mechanisms responsible for this climate deterioration. Here, we present two high-resolution (5–20 years) sea surface temperature (SST) records from the subpolar gyre and off north Iceland in the vicinity of the polar front obtained from alkenone paleo-thermometry and compare them with proxy data from the western Mediterranean Sea to gain information on regional temperature and precipitation patterns. Our results are evidence of a temperature dipole pattern which, combined with other paleo-oceanographic records of the North Atlantic, suggests a weakening of the subpolar gyre possibly associated with atmospheric blocked regimes.