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| Titel |
Characteristics of water-vapour inversions observed over the Arctic by Atmospheric Infrared Sounder (AIRS) and radiosondes |
| VerfasserIn |
A. Devasthale, J. Sedlar, M. Tjernström |
| 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 ; 11, no. 18 ; Nr. 11, no. 18 (2011-09-22), S.9813-9823 |
| Datensatznummer |
250010097
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| Publikation (Nr.) |
 copernicus.org/acp-11-9813-2011.pdf |
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| Zusammenfassung |
An accurate characterization of the vertical structure of the Arctic
atmosphere is useful in climate change and attribution studies as well as
for the climate modelling community to improve projections of future climate
over this highly sensitive region. Here, we investigate one of the dominant
features of the vertical structure of the Arctic atmosphere, i.e.
water-vapour inversions, using eight years of Atmospheric Infrared Sounder
data (2002–2010) and radiosounding profiles released from the two Arctic
locations (North Slope of Alaska at Barrow and during SHEBA). We quantify
the characteristics of clear-sky water vapour inversions in terms of their
frequency of occurrence, strength and height covering the entire Arctic for
the first time.
We found that the frequency of occurrence of water-vapour inversions is
highest during winter and lowest during summer. The inversion strength is,
however, higher during summer. The observed peaks in the median
inversion-layer heights are higher during the winter half of the year, at
around 850 hPa over most of the Arctic Ocean, Siberia and the Canadian
Archipelago, while being around 925 hPa during most of the summer half of
the year over the Arctic Ocean. The radiosounding profiles agree with the
frequency, location and strength of water-vapour inversions in the Pacific
sector of the Arctic. In addition, the radiosoundings indicate that multiple
inversions are the norm with relatively few cases without inversions. The
amount of precipitable water within the water-vapour inversion structures is
estimated and we find a distinct, two-mode contribution to the total column
precipitable water. These results suggest that water-vapour inversions are a
significant source to the column thermodynamics, especially during the
colder winter and spring seasons. We argue that these inversions are a
robust metric to test the reproducibility of thermodynamics within climate
models. An accurate statistical representation of water-vapour inversions in
models would mean that the large-scale coupling of moisture transport,
precipitation, temperature and water-vapour vertical structure and radiation
are essentially captured well in such models. |
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