Using high-resolution tritium profiles to quantify the effects of melt on two Spitsbergen ice cores

Ice cores from small ice caps provide valuable climatic information, additional to that of Greenland and Antarctica. However, their integrity is usually compromised by summer meltwater percolation. To determine to what extent this can affect such ice cores, we performed high-resolution tritium measu...

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Bibliographic Details
Published in:Journal of Glaciology
Main Authors: Wel, L.G. van der, Streurman, H.J., Isaksson, E., Helsen, M.M., Wal, R.S.W. van de, Martma, T., Pohjola, V.A., Moore, J.C., Meijer, H.A.J.
Format: Article in Journal/Newspaper
Language:English
Published: 2011
Subjects:
ISOTOPE RECORDS
CLIMATE
LOMONOSOVFONNA
SVALBARD
WATER
RECONSTRUCTION
GLACIERS
SIGNALS
ISLAND
CAP
Greenland
Lomonosovfonna
Svalbard
Antarc*
Antarctica
ice core
Journal of Glaciology
Spitsbergen
Online Access:https://hdl.handle.net/11370/eb040359-e3e2-4ce7-ac31-7adc12b6e3ef
https://research.rug.nl/en/publications/eb040359-e3e2-4ce7-ac31-7adc12b6e3ef
https://doi.org/10.3189/002214311798843368
Description
Summary:Ice cores from small ice caps provide valuable climatic information, additional to that of Greenland and Antarctica. However, their integrity is usually compromised by summer meltwater percolation. To determine to what extent this can affect such ice cores, we performed high-resolution tritium measurements on samples from two ice cores from Spitsbergen covering the period AD1955-75. The very sharp and distinct peaks in the tritium precipitation record are subject to several post-depositional processes. We developed a model that uses the precipitation record as input and incorporates the three most important processes (radioactive decay, isotope diffusion and meltwater percolation). Results are compared with measured tritium and density profiles. Both ice-core records contain sharp bomb peaks in the pre-1963 period. It is shown that these peaks would be much smoother in the absence of melt. In this case the main effect of melt and the refreezing of percolation water is the formation of ice layers that form barriers for firn diffusion; thus melt paradoxically results in better preservation of the annual isotope signals. Conversely, for the period after 1963 the main effect of melt is a stronger smoothing of the tritium profiles.

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