A late medieval warm period in the Southern Ocean as a delayed response to external forcing?

On the basis of long simulations performed with a three-dimensional climate model, we propose an interhemispheric climate lag mechanism, involving the long-term memory of deepwater masses. Warm anomalies, formed in the North Atlantic when warm conditions prevail at surface, are transported by the de...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Goosse, Hugues, Masson-Delmotte, V., Renssen, H., Delmotte, M., Fichefet, Thierry, Morgan, V, van Ommen, T, Khim, BK, Stenni, B
Other Authors: UCL - SC/PHYS - Département de physique, UCL - SST/ELI/ELIC - Earth & Climate
Format: Article in Journal/Newspaper
Language:English
Published: Amer Geophysical Union 2004
Subjects:
Southern Ocean
North Atlantic
Online Access:http://hdl.handle.net/2078.1/40298
https://doi.org/10.1029/2003GL019140
Description
Summary:On the basis of long simulations performed with a three-dimensional climate model, we propose an interhemispheric climate lag mechanism, involving the long-term memory of deepwater masses. Warm anomalies, formed in the North Atlantic when warm conditions prevail at surface, are transported by the deep ocean circulation towards the Southern Ocean. There, the heat is released because of large scale upwelling, maintaining warm conditions and inducing a lagged response of about 150 years compared to the Northern Hemisphere. Model results and observations covering the first half of the second millenium suggest a delay between the temperature evolution in the Northern Hemisphere and in the Southern Ocean. The mechanism described here provides a reasonable hypothesis to explain such an interhemipsheric lag.

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