The impact of different glacial boundary conditions on atmospheric dynamics and precipitation in the North Atlantic region

Hofer, D.; Raible, C.C.; Dehnert, A.; Kuhlemann, J. (2012). The impact of different glacial boundary conditions on atmospheric dynamics and precipitation in the North Atlantic region. Climate of the past, 8(3), pp. 935-949. Göttingen: Copernicus Publications 10.5194/cp-8-935-2012

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Using a highly resolved atmospheric general circulation model, the impact of different glacial boundary conditions on precipitation and atmospheric dynamics in the North Atlantic region is investigated. Six 30-yr time slice experiments of the Last Glacial Maximum at 21 thousand years before the present (ka BP) and of a less pronounced glacial state – the Middle Weichselian (65 ka BP) – are compared to analyse the sensitivity to changes in the ice sheet distribution, in the radiative forcing and in the prescribed time-varying sea surface temperature and sea ice, which are taken from a lower-resolved, but fully coupled atmosphere-ocean general circulation model. The strongest differences are found for simulations with different heights of the Laurentide ice sheet. A high surface elevation of the Laurentide ice sheet leads to a southward displacement of the jet stream and the storm track in the North Atlantic region. These changes in the atmospheric dynamics generate a band of increased precipitation in the mid-latitudes across the Atlantic to southern Europe in winter, while the precipitation pattern in summer is only marginally affected. The impact of the radiative forcing differences between the two glacial periods and of the prescribed time-varying sea surface temperatures and sea ice are of second order importance compared to the one of the Laurentide ice sheet. They affect the atmospheric dynamics and precipitation in a similar but less pronounced manner compared with the topographic changes.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Climate and Environmental Physics

UniBE Contributor:

Hofer, Dominik and Raible, Christoph

ISSN:

1814-9324

Publisher:

Copernicus Publications

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:44

Last Modified:

07 Dec 2014 09:57

Publisher DOI:

10.5194/cp-8-935-2012

BORIS DOI:

10.7892/boris.18171

URI:

https://boris.unibe.ch/id/eprint/18171 (FactScience: 226037)

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