Non-climatic signal in ice core records: lessons from Antarctic megadunes
We present the results of glaciological investigations in the megadune area located 30 km to the east of Vostok Station (central East Antarctica) implemented during the 58th, 59th and 60th Russian Antarctic Expedition (January 2013–2015). Snow accumulation rate and isotope content ( δ D , δ 18 O and...
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ftcopernicus:oai:publications.copernicus.org:tc48279 2023-05-15T13:54:27+02:00 Non-climatic signal in ice core records: lessons from Antarctic megadunes Ekaykin, Alexey Eberlein, Lutz Lipenkov, Vladimir Popov, Sergey Scheinert, Mirko Schröder, Ludwig Turkeev, Alexey 2018-09-27 application/pdf https://doi.org/10.5194/tc-10-1217-2016 https://tc.copernicus.org/articles/10/1217/2016/ eng eng doi:10.5194/tc-10-1217-2016 https://tc.copernicus.org/articles/10/1217/2016/ eISSN: 1994-0424 Text 2018 ftcopernicus https://doi.org/10.5194/tc-10-1217-2016 2020-07-20T16:24:08Z We present the results of glaciological investigations in the megadune area located 30 km to the east of Vostok Station (central East Antarctica) implemented during the 58th, 59th and 60th Russian Antarctic Expedition (January 2013–2015). Snow accumulation rate and isotope content ( δ D , δ 18 O and δ 17 O) were measured along the 2 km profile across the megadune ridge accompanied by precise GPS altitude measurements and ground penetrating radar (GPR) survey. It is shown that the spatial variability of snow accumulation and isotope content covaries with the surface slope. The accumulation rate regularly changes by 1 order of magnitude within the distance < 1 km, with the reduced accumulation at the leeward slope of the dune and increased accumulation in the hollow between the dunes. At the same time, the accumulation rate averaged over the length of a dune wave (22 mm w.e.) corresponds well with the value obtained at Vostok Station, which suggests no additional wind-driven snow sublimation in the megadunes compared to the surrounding plateau. The snow isotopic composition is in negative correlation with the snow accumulation. Analysing dxs ∕ δ D and 17 O-excess ∕ δ D slopes (where dxs = δ D − 8 ⋅ δ 18 O and 17 O-excess = ln( δ 17 O ∕ 1000 + 1) −0.528 ⋅ ln ( δ 18 O ∕ 1000 + 1)), we conclude that the spatial variability of the snow isotopic composition in the megadune area could be explained by post-depositional snow modifications. Using the GPR data, we estimated the apparent dune drift velocity (4.6 ± 1.1 m yr −1 ). The full cycle of the dune drift is thus about 410 years. Since the spatial anomalies of snow accumulation and isotopic composition are supposed to drift with the dune, a core drilled in the megadune area would exhibit the non-climatic 410-year cycle of these two parameters. We simulated a vertical profile of snow isotopic composition with such a non-climatic variability, using the data on the dune size and velocity. This artificial profile is then compared with the real vertical profile of snow isotopic composition obtained from a core drilled in the megadune area. We note that the two profiles are very similar. The obtained results are discussed in terms of interpretation of data obtained from ice cores drilled beyond the megadune areas. Text Antarc* Antarctic Antarctica East Antarctica ice core Copernicus Publications: E-Journals Antarctic East Antarctica Vostok Station ENVELOPE(106.837,106.837,-78.464,-78.464) The Cryosphere 10 3 1217 1227 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
We present the results of glaciological investigations in the megadune area located 30 km to the east of Vostok Station (central East Antarctica) implemented during the 58th, 59th and 60th Russian Antarctic Expedition (January 2013–2015). Snow accumulation rate and isotope content ( δ D , δ 18 O and δ 17 O) were measured along the 2 km profile across the megadune ridge accompanied by precise GPS altitude measurements and ground penetrating radar (GPR) survey. It is shown that the spatial variability of snow accumulation and isotope content covaries with the surface slope. The accumulation rate regularly changes by 1 order of magnitude within the distance < 1 km, with the reduced accumulation at the leeward slope of the dune and increased accumulation in the hollow between the dunes. At the same time, the accumulation rate averaged over the length of a dune wave (22 mm w.e.) corresponds well with the value obtained at Vostok Station, which suggests no additional wind-driven snow sublimation in the megadunes compared to the surrounding plateau. The snow isotopic composition is in negative correlation with the snow accumulation. Analysing dxs ∕ δ D and 17 O-excess ∕ δ D slopes (where dxs = δ D − 8 ⋅ δ 18 O and 17 O-excess = ln( δ 17 O ∕ 1000 + 1) −0.528 ⋅ ln ( δ 18 O ∕ 1000 + 1)), we conclude that the spatial variability of the snow isotopic composition in the megadune area could be explained by post-depositional snow modifications. Using the GPR data, we estimated the apparent dune drift velocity (4.6 ± 1.1 m yr −1 ). The full cycle of the dune drift is thus about 410 years. Since the spatial anomalies of snow accumulation and isotopic composition are supposed to drift with the dune, a core drilled in the megadune area would exhibit the non-climatic 410-year cycle of these two parameters. We simulated a vertical profile of snow isotopic composition with such a non-climatic variability, using the data on the dune size and velocity. This artificial profile is then compared with the real vertical profile of snow isotopic composition obtained from a core drilled in the megadune area. We note that the two profiles are very similar. The obtained results are discussed in terms of interpretation of data obtained from ice cores drilled beyond the megadune areas. |
format |
Text |
author |
Ekaykin, Alexey Eberlein, Lutz Lipenkov, Vladimir Popov, Sergey Scheinert, Mirko Schröder, Ludwig Turkeev, Alexey |
spellingShingle |
Ekaykin, Alexey Eberlein, Lutz Lipenkov, Vladimir Popov, Sergey Scheinert, Mirko Schröder, Ludwig Turkeev, Alexey Non-climatic signal in ice core records: lessons from Antarctic megadunes |
author_facet |
Ekaykin, Alexey Eberlein, Lutz Lipenkov, Vladimir Popov, Sergey Scheinert, Mirko Schröder, Ludwig Turkeev, Alexey |
author_sort |
Ekaykin, Alexey |
title |
Non-climatic signal in ice core records: lessons from Antarctic megadunes |
title_short |
Non-climatic signal in ice core records: lessons from Antarctic megadunes |
title_full |
Non-climatic signal in ice core records: lessons from Antarctic megadunes |
title_fullStr |
Non-climatic signal in ice core records: lessons from Antarctic megadunes |
title_full_unstemmed |
Non-climatic signal in ice core records: lessons from Antarctic megadunes |
title_sort |
non-climatic signal in ice core records: lessons from antarctic megadunes |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-10-1217-2016 https://tc.copernicus.org/articles/10/1217/2016/ |
long_lat |
ENVELOPE(106.837,106.837,-78.464,-78.464) |
geographic |
Antarctic East Antarctica Vostok Station |
geographic_facet |
Antarctic East Antarctica Vostok Station |
genre |
Antarc* Antarctic Antarctica East Antarctica ice core |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica ice core |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-10-1217-2016 https://tc.copernicus.org/articles/10/1217/2016/ |
op_doi |
https://doi.org/10.5194/tc-10-1217-2016 |
container_title |
The Cryosphere |
container_volume |
10 |
container_issue |
3 |
container_start_page |
1217 |
op_container_end_page |
1227 |
_version_ |
1766260338525732864 |