Atmosphere and ocean dynamics: Contributors to the European Little Ice Age?

Palastanga, V, Van Der Schrier, G, Weber, SL, Kleinen, T, Briffa, KR and Osborn, TJ (2011) Atmosphere and ocean dynamics: Contributors to the European Little Ice Age? Climate Dynamics, 36 (5-6). pp. 973-987.

Full text not available from this repository. (Request a copy)

Abstract

The role of a reduction in the Atlantic meridional overturning and that of a persistently negative North Atlantic Oscillation in explaining the coldness of the European Little Ice Age (LIA) has been assessed in two sets of numerical experiments. These experiments are performed using an intermediate complexity climate model and a full complexity GCM. The reduction in the Meridional Overturning Circulation (MOC) of ca. 25% is triggered by a conventional fresh-water hosing set-up. A persistently negative NAO winter circulation, at NAO-index value -0.5, is imposed using recently developed data-assimilation techniques applicable on paleoclimatic timescales. The hosing experiments lead to a reduction in oceanic meridional heat transport and cooler sea-surface temperatures. Next to a direct cooling effect on European climate, the change in ocean surface temperatures feedback on the atmospheric circulation modifying European climate significantly. The data-assimilation experiments showed a reduction of winter temperatures over parts of Europe, but there is little persistence into the summer season. The output of all model experiments are compared to reconstructions of winter and summer temperature based on the available temperature data for the LIA period. This demonstrates that the hypothesis of a persistently negative NAO as an explanation for the European LIA does not hold. The hosing experiments do not clearly support the hypothesis that a reduction in the MOC is the primary driver of LIA climate change. However, a reduction in the Atlantic overturning might have been a cause of the European LIA climate, depending on whether there is a strong enough feedback on the atmospheric circulation.

Item Type: Article
Faculty \ School: Faculty of Science > School of Environmental Sciences
Related URLs:
Depositing User: Rosie Cullington
Date Deposited: 15 Feb 2011 15:01
Last Modified: 13 Mar 2019 10:31
URI: https://ueaeprints.uea.ac.uk/id/eprint/20383
DOI: 10.1007/s00382-010-0751-0

Actions (login required)

View Item