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Change in CO 2 concentration and O 2 /N 2 ratio in ice cores due to molecular diffusion
Author(s) -
Bereiter Bernhard,
Schwander Jakob,
Lüthi Dieter,
Stocker Thomas F.
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl036737
Subject(s) - ice core , diffusion , clathrate hydrate , analytical chemistry (journal) , materials science , polar , mineralogy , chemistry , thermodynamics , geology , hydrate , physics , environmental chemistry , climatology , organic chemistry , astronomy
Polar ice cores are unique archives for ancient air. However, a loss of air due to molecular diffusion during storage could affect the composition of the remaining air. We formulate a model with a high spatial resolution (1 mm) calculating the loss of N 2 , O 2 and CO 2 in pure clathrate ice in order to determine which layers of an ice core are affected by significant changes in the CO 2 concentration and the δ (O 2 /N 2 ) ratio for storage durations up to 38 years. The results agree with experimental δ (O 2 /N 2 ) measurements at ice core pieces performed after different storage durations. Additionally, the calculations confirm the importance of the storage temperature and show that the CO 2 concentration is less affected than that of δ (O 2 /N 2 ). Furthermore, guidelines for ice core sample preparation are provided in dependence of storage duration and temperature.