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Impact of Local Insolation on Snow Metamorphism and Ice Core Records

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Please use this identifier to cite or link to this item:http://hdl.handle.net/2115/45450

Title: Impact of Local Insolation on Snow Metamorphism and Ice Core Records
Authors: Hutterli, Manuel A. Browse this author
Schneebeli, Martin Browse this author
Freitag, Johannes Browse this author
Kipfstuhl, Josef Browse this author
Röthlisberger, Regine Browse this author
Keywords: Local insolation
snow
firn
temperature gradient metamorphism
ice core records
Dome Fuji
Issue Date: Dec-2009
Publisher: Institute of Low Temperature Science, Hokkaido University
Citation: Physics of Ice Core Records II : Papers collected after the 2nd International Workshop on Physics of Ice Core Records, held in Sapporo, Japan, 2-6 February 2007. Edited by Takeo Hondoh
Journal Title: 低温科学
Journal Title(alt): Low Temperature Science
Volume: 68
Issue: Supplement
Start Page: 223
End Page: 232
Abstract: Local insolation is a major component of the energy balance at the surface of an ice sheet and causes temperature gradient metamorphism (TGM) of snow and firn. TGM is one of the dominant processes changing the structure of dry snow. We present a physically based model that calculates insolation-induced relative changes in TGM in the past. The results indicate that TGM at Dome Fuji varied by up to a factor of 2 over the past 350ka, and is driven predominately by the precession-band variability in local summer solstice insolation. At Dome Fuji, the impact of glacial-interglacial temperature changes on TGM is almost fully compensated by synchronous, opposite changes in accumulation rate, which determines the exposure time of a snow layer to TGM. Even small remaining temperature signals in TGM can cause phase shifts between TGM and local summer solstice insolation of several ka. This directly affects the accuracy of orbitally tuned ice core time scales using O2/N2 or total air content records, as this dating method is based on the assumption of synchronicity between TGM and insolation. It must be assumed that the strong variability in TGM will also be reflected in physical and chemical ice core records by e.g. modulating the volatilization of reversibly deposited species including the stable isotopes of water. Sublimation and thus accumulation rates are also closely linked to TGM, affecting the concentrations also of irreversibly deposited non-volatile impurities. Thus, the effect of a local, post-depositional contribution of TGM on ice core records must be quantified prior to their interpretation in terms of larger scale climate variability in the orbital frequency bands.
Description: III. Firn densification, close-off and chronology
Type: bulletin (article)
URI: http://hdl.handle.net/2115/45450
Appears in Collections:低温科学 = Low Temperature Science > vol. 68, Supplement Issue

Submitter: 低温科学研究所図書室

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