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Titel |
Continuous monitoring of summer surface water vapor isotopic composition above the Greenland Ice Sheet |
VerfasserIn |
H. C. Steen-Larsen, S. J. Johnsen, V. Masson-Delmotte, B. Stenni, C. Risi, H. Sodemann, D. Balslev-Clausen, T. Blunier, D. Dahl-Jensen, M. D. Ellehøj, S. Falourd, A. Grindsted, V. Gkinis, J. Jouzel, T. Popp, S. Sheldon, S. B. Simonsen, J. Sjolte, J. P. Steffensen, P. Sperlich, Á. E. Sveinbjörnsdóttir, B. M. Vinther, J. W. C. White |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 9 ; Nr. 13, no. 9 (2013-05-13), S.4815-4828 |
Datensatznummer |
250018642
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Publikation (Nr.) |
copernicus.org/acp-13-4815-2013.pdf |
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Zusammenfassung |
We present here surface water vapor isotopic measurements conducted from
June to August 2010 at the NEEM (North Greenland Eemian Drilling
Project) camp, NW Greenland (77.45° N,
51.05° W, 2484 m a.s.l.). Measurements were conducted at 9
different heights from 0.1 m to 13.5 m above the snow surface using
two different types of cavity-enhanced near-infrared absorption spectroscopy
analyzers. For each instrument specific protocols were developed for
calibration and drift corrections. The inter-comparison of corrected results
from different instruments reveals excellent reproducibility, stability, and
precision with a standard deviations of ~ 0.23‰ for δ18O and ~ 1.4‰ for δD. Diurnal and intraseasonal variations
show strong relationships between changes in local surface humidity and
water vapor isotopic composition, and with local and synoptic weather
conditions. This variability probably results from the interplay between
local moisture fluxes, linked with firn–air exchanges, boundary layer
dynamics, and large-scale moisture advection. Particularly remarkable are
several episodes characterized by high (> 40‰) surface water vapor deuterium excess. Air mass
back-trajectory calculations from atmospheric analyses and water tagging in
the LMDZiso (Laboratory of Meteorology Dynamics Zoom-isotopic) atmospheric model reveal that these events are associated with
predominant Arctic air mass origin. The analysis suggests that high
deuterium excess levels are a result of strong kinetic fractionation during
evaporation at the sea-ice margin. |
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