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| Titel |
The isotopic composition of water vapour and precipitation in Ivittuut, southern Greenland |
| VerfasserIn |
J.-L. Bonne, V. Masson-Delmotte, O. Cattani, M. Delmotte, C. Risi, H. Sodemann, H. C. Steen-Larsen |
| 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 ; 14, no. 9 ; Nr. 14, no. 9 (2014-05-07), S.4419-4439 |
| Datensatznummer |
250118681
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| Publikation (Nr.) |
 copernicus.org/acp-14-4419-2014.pdf |
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| Zusammenfassung |
Since September 2011, a wavelength-scanned cavity ring-down spectroscopy
analyser has been remotely operated in Ivittuut, southern Greenland,
providing the first record of surface water vapour isotopic composition based
on continuous measurements in South Greenland and the first record including
the winter season in Greenland. The comparison of vapour data with
measurements of precipitation isotopic composition suggest an equilibrium
between surface vapour and precipitation.
δ18O and deuterium excess are generally anti-correlated and show
important seasonal variations, with respective amplitudes of ~10 and
~20‰, as well as large synoptic variations. The data depict
small summer diurnal variations. At the seasonal scale, δ18O has a
minimum in November–December and a maximum in June–July, while deuterium
excess has a minimum in May–June and a maximum in November. The approach of low-pressure systems towards South Greenland leads to δ18O increase
(typically +5‰) and deuterium excess decrease (typically
−15‰).
Seasonal and synoptic variations coincide with shifts in the moisture
sources, estimated using a quantitative moisture source diagnostic based on a
Lagrangian back-trajectory model. The atmospheric general circulation
model LMDZiso correctly captures the seasonal and synoptic variability of
δ18O, but does not capture the observed magnitude of deuterium
excess variability.
Covariations of water vapour isotopic composition with local and moisture
source meteorological parameters have been evaluated. δ18O is
strongly correlated with the logarithm of local surface humidity, consistent
with Rayleigh distillation processes, and with local surface air temperature,
associated with a slope of ~0.4‰ °C−1. Deuterium
excess correlates with local surface relative humidity as well as surface
relative humidity from the dominant moisture source area located in the North
Atlantic, south of Greenland and Iceland. |
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