Three-year monitoring of stable isotopes of precipitation at Concordia Station, East Antarctica
International audience Past temperature reconstructions from Antarctic ice cores require a good quantification and understanding of the relationship between snow isotopic composition and 2 m air or inversion (condensation) temperature. Here, we focus on the French–Italian Concordia Station, central...
Published in: | The Cryosphere |
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Main Authors: | , , , , , , , , , , , , |
Other Authors: | , , , , , , , , , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2016
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Subjects: | |
Online Access: | https://hal.sorbonne-universite.fr/hal-01398029 https://hal.sorbonne-universite.fr/hal-01398029/document https://hal.sorbonne-universite.fr/hal-01398029/file/tc-10-2415-2016.pdf https://doi.org/10.5194/tc-10-2415-2016 |
Summary: | International audience Past temperature reconstructions from Antarctic ice cores require a good quantification and understanding of the relationship between snow isotopic composition and 2 m air or inversion (condensation) temperature. Here, we focus on the French–Italian Concordia Station, central East Antarctic plateau, where the European Project for Ice Coring in Antarctica (EPICA) Dome C ice cores were drilled. We provide a multi-year record of daily precipitation types identified from crystal morphologies, daily precipitation amounts and isotopic composition. Our sampling period (2008–2010) encompasses a warmer year (2009, +1.2 • C with respect to 2 m air temperature long-term average 1996–2010), with larger total precipitation and snowfall amounts (14 and 76 % above sampling period average, respectively), and a colder and drier year (2010, −1.8 • C, 4 % below long-term and sampling period averages, respectively) with larger diamond dust amounts (49 % above sampling period average). Relationships between local meteorological data and precipitation isotopic composition are investigated at daily, monthly and inter-annual scale, and for the different types of precipitation. Water stable isotopes are more closely related to 2 m air temperature than to inversion temperature at all timescales (e.g. R 2 = 0.63 and 0.44, respectively for daily values). The slope of the temporal relationship between daily δ 18 O and 2 m air temperature is approximately 2 times smaller (0.49 ‰ • C −1) than the average Antarctic spatial (0.8 ‰ • C −1) relationship initially used for the interpretation of EPICA Dome C records. In accordance with results from precipitation monitoring at Vostok and Dome F, deuterium excess is anti-correlated with δ 18 O at daily and monthly scales, reaching maximum values in winter. Hoar frost precipitation samples have a specific fingerprint with more depleted δ 18 O (about 5 ‰ below average) and higher deuterium excess (about 8 ‰ above average) values than other precipitation types. These datasets ... |
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