Estimation of gas record alteration in very low-accumulation ice cores
We measured the methane mixing ratios of enclosed air in five ice core sections drilled on the East Antarctic Plateau. Our work aims to study two effects that alter the recorded gas concentrations in ice cores: layered gas trapping artifacts and firn smoothing. Layered gas trapping artifacts are due...
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Online Access: | https://doi.org/10.5194/cp-16-503-2020 https://cp.copernicus.org/articles/16/503/2020/ |
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fttriple:oai:gotriple.eu:Q4Fb8ipPPiWx5Bo7FMGVR 2023-05-15T13:43:26+02:00 Estimation of gas record alteration in very low-accumulation ice cores Fourteau, Kévin Martinerie, Patricia Faïn, Xavier Ekaykin, Alexey A. Chappellaz, Jérôme Lipenkov, Vladimir 2020-03-11 https://doi.org/10.5194/cp-16-503-2020 https://cp.copernicus.org/articles/16/503/2020/ en eng doi:10.5194/cp-16-503-2020 10670/1.4cx2nz https://cp.copernicus.org/articles/16/503/2020/ other Geographica Helvetica - geography eISSN: 1814-9332 geo envir Other https://vocabularies.coar-repositories.org/resource_types/c_1843/ 2020 fttriple https://doi.org/10.5194/cp-16-503-2020 2023-01-22T17:54:27Z We measured the methane mixing ratios of enclosed air in five ice core sections drilled on the East Antarctic Plateau. Our work aims to study two effects that alter the recorded gas concentrations in ice cores: layered gas trapping artifacts and firn smoothing. Layered gas trapping artifacts are due to the heterogeneous nature of polar firn, where some strata might close early and trap abnormally old gases that appear as spurious values during measurements. The smoothing is due to the combined effects of diffusive mixing in the firn and the progressive closure of bubbles at the bottom of the firn. Consequently, the gases trapped in a given ice layer span a distribution of ages. This means that the gas concentration in an ice layer is the average value over a certain period of time, which removes the fast variability from the record. Here, we focus on the study of East Antarctic Plateau ice cores, as these low-accumulation ice cores are particularly affected by both layering and smoothing. We use high-resolution methane data to test a simple trapping model reproducing the layered gas trapping artifacts for different accumulation conditions typical of the East Antarctic Plateau. We also use the high-resolution methane measurements to estimate the gas age distributions of the enclosed air in the five newly measured ice core sections. It appears that for accumulations below 2 cm ice equivalent yr−1 the gas records experience nearly the same degree of smoothing. We therefore propose to use a single gas age distribution to represent the firn smoothing observed in the glacial ice cores of the East Antarctic Plateau. Finally, we used the layered gas trapping model and the estimation of glacial firn smoothing to quantify their potential impacts on a hypothetical 1.5-million-year-old ice core from the East Antarctic Plateau. Our results indicate that layering artifacts are no longer individually resolved in the case of very thinned ice near the bedrock. They nonetheless contribute to slight biases of the measured signal ... Other/Unknown Material Antarc* Antarctic ice core Unknown Antarctic Climate of the Past 16 2 503 522 |
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geo envir Fourteau, Kévin Martinerie, Patricia Faïn, Xavier Ekaykin, Alexey A. Chappellaz, Jérôme Lipenkov, Vladimir Estimation of gas record alteration in very low-accumulation ice cores |
topic_facet |
geo envir |
description |
We measured the methane mixing ratios of enclosed air in five ice core sections drilled on the East Antarctic Plateau. Our work aims to study two effects that alter the recorded gas concentrations in ice cores: layered gas trapping artifacts and firn smoothing. Layered gas trapping artifacts are due to the heterogeneous nature of polar firn, where some strata might close early and trap abnormally old gases that appear as spurious values during measurements. The smoothing is due to the combined effects of diffusive mixing in the firn and the progressive closure of bubbles at the bottom of the firn. Consequently, the gases trapped in a given ice layer span a distribution of ages. This means that the gas concentration in an ice layer is the average value over a certain period of time, which removes the fast variability from the record. Here, we focus on the study of East Antarctic Plateau ice cores, as these low-accumulation ice cores are particularly affected by both layering and smoothing. We use high-resolution methane data to test a simple trapping model reproducing the layered gas trapping artifacts for different accumulation conditions typical of the East Antarctic Plateau. We also use the high-resolution methane measurements to estimate the gas age distributions of the enclosed air in the five newly measured ice core sections. It appears that for accumulations below 2 cm ice equivalent yr−1 the gas records experience nearly the same degree of smoothing. We therefore propose to use a single gas age distribution to represent the firn smoothing observed in the glacial ice cores of the East Antarctic Plateau. Finally, we used the layered gas trapping model and the estimation of glacial firn smoothing to quantify their potential impacts on a hypothetical 1.5-million-year-old ice core from the East Antarctic Plateau. Our results indicate that layering artifacts are no longer individually resolved in the case of very thinned ice near the bedrock. They nonetheless contribute to slight biases of the measured signal ... |
format |
Other/Unknown Material |
author |
Fourteau, Kévin Martinerie, Patricia Faïn, Xavier Ekaykin, Alexey A. Chappellaz, Jérôme Lipenkov, Vladimir |
author_facet |
Fourteau, Kévin Martinerie, Patricia Faïn, Xavier Ekaykin, Alexey A. Chappellaz, Jérôme Lipenkov, Vladimir |
author_sort |
Fourteau, Kévin |
title |
Estimation of gas record alteration in very low-accumulation ice cores |
title_short |
Estimation of gas record alteration in very low-accumulation ice cores |
title_full |
Estimation of gas record alteration in very low-accumulation ice cores |
title_fullStr |
Estimation of gas record alteration in very low-accumulation ice cores |
title_full_unstemmed |
Estimation of gas record alteration in very low-accumulation ice cores |
title_sort |
estimation of gas record alteration in very low-accumulation ice cores |
publishDate |
2020 |
url |
https://doi.org/10.5194/cp-16-503-2020 https://cp.copernicus.org/articles/16/503/2020/ |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic ice core |
genre_facet |
Antarc* Antarctic ice core |
op_source |
Geographica Helvetica - geography eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-16-503-2020 10670/1.4cx2nz https://cp.copernicus.org/articles/16/503/2020/ |
op_rights |
other |
op_doi |
https://doi.org/10.5194/cp-16-503-2020 |
container_title |
Climate of the Past |
container_volume |
16 |
container_issue |
2 |
container_start_page |
503 |
op_container_end_page |
522 |
_version_ |
1766189053279993856 |