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| Titel |
Sampled precipitation and atmospheric water vapour from NEEM – The North Greenland Eemian Ice Drilling |
| VerfasserIn |
H. C. Steen-Larsen, V. Masson-Delmotte, S. J. Johnsen, B. M. Vinther |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250019465
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| Zusammenfassung |
| To interpret the climatic signal obtained from stable isotope records from ice cores, it is
important to understand the processes governing the snow-atmosphere interaction and the
processes which bring moisture from the source to the ice core site. This requires sampling of
precipitation and water vapour above the snow, which is not often performed simultaneous at
ice core drill sites.
As a side project under NEEM - a new deep drilling project in NW Greenland (77.5N,
50.9W, 2484m a.s.l.) - precipitation and atmospheric water vapour were sampled in the
season of 2008 from end of June to end of August on a sub-event and sub-daily basis,
respectively. We present here the results of δD and δ18O measurements on all samples
collected.
The precipitation samples were collected on a table during snow events about every three
hours. Atmospheric water vapour was sampled at three meters height above the snow surface
and was collected using cryogenic cooling. The atmospheric water vapour was collected
every morning and evening.
The water vapour samples reveal large sub-daily variations of up to 30 per mill
change in δD during 24 hours and a spread of 100 per mill in δD during the season.
During precipitation events it is found in general that the isotopic composition
of the atmospheric water vapour is in equilibrium with that of the precipitating
snow.
It is furthermore found that plotting δD vs. δ18O for the water vapour samples and for the
precipitation samples reveal a good linear correlation. For the sampled water vapour the slope
is 6.9 while for the precipitation samples the slope is 7.6. The slope of the precipitation
samples is comparable to the slope of the summer snow retrieved from a shallow firn core
drilled in the vicinity. |
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