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| Titel |
Variations of oxygen-18 in West Siberian precipitation during the last 50 years |
| VerfasserIn |
M. Butzin, M. Werner, V. Masson-Delmotte, C. Risi, C. Frankenberg, K. Gribanov, J. Jouzel, V. I. Zakharov |
| 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. 11 ; Nr. 14, no. 11 (2014-06-13), S.5853-5869 |
| Datensatznummer |
250118791
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| Publikation (Nr.) |
 copernicus.org/acp-14-5853-2014.pdf |
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| Zusammenfassung |
| Global warming is associated with large increases in surface air temperature
in Siberia. Here, we apply the isotope-enabled atmospheric general
circulation model ECHAM5-wiso to explore the potential of water isotope
measurements at a recently opened monitoring station in Kourovka
(57.04° N, 59.55° E) in order to successfully trace climate
change in western Siberia. Our model is constrained to atmospheric reanalysis
fields for the period 1957–2013 to facilitate the comparison with
observations of δD in total column water vapour from the GOSAT
satellite, and with precipitation δ18O measurements from 15 Russian
stations of the Global Network of Isotopes in Precipitation. The model
captures the observed Russian climate within reasonable error margins, and
displays the observed isotopic gradients associated with increasing
continentality and decreasing meridional temperatures. The model also
reproduces the observed seasonal cycle of δ18O, which parallels the
seasonal cycle of temperature and ranges from −25 ‰ in winter to
−5 ‰ in summer. Investigating West Siberian climate and
precipitation δ18O variability during the last 50 years, we find
long-term increasing trends in temperature and δ18O, while
precipitation trends are uncertain. During the last 50 years, winter
temperatures have increased by 1.7 °C. The simulated long-term
increase of precipitation δ18O is at the detection limit
(<1 ‰ per 50 years) but significant. West Siberian climate is
characterized by strong interannual variability, which in winter is strongly
related to the North Atlantic Oscillation. In winter, regional temperature is
the predominant factor controlling δ18O variations on interannual
to decadal timescales with a slope of about 0.5 ‰ °C−1.
In summer, the interannual variability of δ18O can be attributed to
short-term, regional-scale processes such as evaporation and convective
precipitation. This finding suggests that precipitation δ18O has
the potential to reveal hydrometeorological regime shifts in western Siberia
which are otherwise difficult to identify. Focusing on Kourovka, the
simulated evolution of temperature, δ18O and, to a smaller extent,
precipitation during the last 50 years is synchronous with model results
averaged over all of western Siberia, suggesting that this site will be
representative to monitor future isotopic changes in the entire region. |
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