Large-scale drivers of Caucasus climate variability in meteorological records and Mt El'brus ice cores
A 181.8 m ice core was recovered from a borehole drilled into bedrock on the western plateau of Mt El'brus (43°20′53.9′′ N, 42°25′36.0′′ E; 5115 m a.s.l.) in the Caucasus, Russia, in 2009 (Mikhalenko et al., 2015). Here, we report on the results of the water stable isotope composition from this...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-05-01
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| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/13/473/2017/cp-13-473-2017.pdf |
| Summary: | A 181.8 m ice core was recovered from a borehole drilled into
bedrock on the western plateau of Mt El'brus (43°20′53.9′′ N,
42°25′36.0′′ E; 5115 m a.s.l.) in the Caucasus, Russia, in
2009 (Mikhalenko et al., 2015). Here, we report on the results of the water
stable isotope composition from this ice core with additional data from the
shallow cores. The distinct seasonal cycle of the isotopic composition allows
dating by annual layer counting. Dating has been performed for the upper
126 m of the deep core combined with 20 m from the shallow cores. The whole
record covers 100 years, from 2013 back to 1914. Due to the high accumulation
rate (1380 mm w.e. year<sup>−1</sup>) and limited
melting, we obtained isotopic composition and accumulation rate records with
seasonal resolution. These values were compared with available meteorological
data from 13 weather stations in the region and also with atmosphere
circulation indices, back-trajectory calculations, and Global Network of
Isotopes in Precipitation (GNIP) data in order to decipher the drivers of
accumulation and ice core isotopic composition in the Caucasus region. In the
warm season (May–October) the isotopic composition depends on local
temperatures, but the correlation is not persistent over time, while in the
cold season (November–April), atmospheric circulation is the predominant
driver of the ice core's isotopic composition. The snow accumulation rate
correlates well with the precipitation rate in the region all year round,
which made it possible to reconstruct and expand the precipitation record at
the Caucasus highlands from 1914 until 1966, when reliable meteorological
observations of precipitation at high elevation began. |
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| ISSN: | 1814-9324 1814-9332 |