Atmospheric impacts and ice core imprints of a methane pulse from clathrates
In relation to Arctic warming, the possible occurrence of methane hydrate degassing events has attracted an increasing interest in recent years. We evaluate the atmospheric impact of rapid and massive emissions of methane and how they are imprinted in ice core records, by combining for the first tim...
Published in: | Earth and Planetary Science Letters |
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Online Access: | https://doi.org/10.1016/j.epsl.2012.06.052 http://infoscience.epfl.ch/record/298281 |
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ftinfoscience:oai:infoscience.epfl.ch:298281 2023-05-15T13:43:17+02:00 Atmospheric impacts and ice core imprints of a methane pulse from clathrates Bock, J. Martinerie, P. Witrant, E. Chappellaz, J. 2022-11-23T16:11:06Z https://doi.org/10.1016/j.epsl.2012.06.052 http://infoscience.epfl.ch/record/298281 unknown Elsevier BV doi:10.1016/j.epsl.2012.06.052 http://infoscience.epfl.ch/record/298281 http://infoscience.epfl.ch/record/298281 Text 2022 ftinfoscience https://doi.org/10.1016/j.epsl.2012.06.052 2023-02-13T23:12:29Z In relation to Arctic warming, the possible occurrence of methane hydrate degassing events has attracted an increasing interest in recent years. We evaluate the atmospheric impact of rapid and massive emissions of methane and how they are imprinted in ice core records, by combining for the first time models of atmospheric chemistry and trace gas transport in firn. Different emission characteristics as well as climatic conditions (present, pre-industrial, glacial) are considered. The δ isotopic signatures characterizing stable isotopologues of methane DCH 3 and 13CH 4 are also analysed. Our results suggest little effect of clathrate degassing on the main methane oxidant: OH radicals. Due to the relatively short atmospheric lifetime of methane, the simulated clathrate-induced perturbations last for less than a century. This time scale is comparable to or shorter than the duration of air bubble closure in polar ice sheets. As a consequence, rapid methane perturbations in the atmosphere are strongly smoothed in ice core records. This smoothing mostly depends on the snow accumulation rate at the site of ice core drilling. We propose a methodology to identify a potential clathrate degassing event in ice core records. Continuous CH 4 records from high accumulation rate sites could allow to decipher short time scale events δD of CH 4 should reveal a typical "lying S" shape at high accumulation rate sites, reflecting the combined effects of the clathrate source signature (negative excursion) and subsequent OH fractionation in the atmosphere (positive excursion). The amplitude ratio of the negative and positive δD swings recorded in Greenland and Antarctica under similar accumulation rate conditions could also indicate the latitude of a clathrate degassing event. © 2012 Elsevier B.V. Text Antarc* Antarctica Arctic Greenland ice core Methane hydrate EPFL Infoscience (Ecole Polytechnique Fédérale Lausanne) Arctic Greenland Earth and Planetary Science Letters 349-350 98 108 |
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EPFL Infoscience (Ecole Polytechnique Fédérale Lausanne) |
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ftinfoscience |
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In relation to Arctic warming, the possible occurrence of methane hydrate degassing events has attracted an increasing interest in recent years. We evaluate the atmospheric impact of rapid and massive emissions of methane and how they are imprinted in ice core records, by combining for the first time models of atmospheric chemistry and trace gas transport in firn. Different emission characteristics as well as climatic conditions (present, pre-industrial, glacial) are considered. The δ isotopic signatures characterizing stable isotopologues of methane DCH 3 and 13CH 4 are also analysed. Our results suggest little effect of clathrate degassing on the main methane oxidant: OH radicals. Due to the relatively short atmospheric lifetime of methane, the simulated clathrate-induced perturbations last for less than a century. This time scale is comparable to or shorter than the duration of air bubble closure in polar ice sheets. As a consequence, rapid methane perturbations in the atmosphere are strongly smoothed in ice core records. This smoothing mostly depends on the snow accumulation rate at the site of ice core drilling. We propose a methodology to identify a potential clathrate degassing event in ice core records. Continuous CH 4 records from high accumulation rate sites could allow to decipher short time scale events δD of CH 4 should reveal a typical "lying S" shape at high accumulation rate sites, reflecting the combined effects of the clathrate source signature (negative excursion) and subsequent OH fractionation in the atmosphere (positive excursion). The amplitude ratio of the negative and positive δD swings recorded in Greenland and Antarctica under similar accumulation rate conditions could also indicate the latitude of a clathrate degassing event. © 2012 Elsevier B.V. |
format |
Text |
author |
Bock, J. Martinerie, P. Witrant, E. Chappellaz, J. |
spellingShingle |
Bock, J. Martinerie, P. Witrant, E. Chappellaz, J. Atmospheric impacts and ice core imprints of a methane pulse from clathrates |
author_facet |
Bock, J. Martinerie, P. Witrant, E. Chappellaz, J. |
author_sort |
Bock, J. |
title |
Atmospheric impacts and ice core imprints of a methane pulse from clathrates |
title_short |
Atmospheric impacts and ice core imprints of a methane pulse from clathrates |
title_full |
Atmospheric impacts and ice core imprints of a methane pulse from clathrates |
title_fullStr |
Atmospheric impacts and ice core imprints of a methane pulse from clathrates |
title_full_unstemmed |
Atmospheric impacts and ice core imprints of a methane pulse from clathrates |
title_sort |
atmospheric impacts and ice core imprints of a methane pulse from clathrates |
publisher |
Elsevier BV |
publishDate |
2022 |
url |
https://doi.org/10.1016/j.epsl.2012.06.052 http://infoscience.epfl.ch/record/298281 |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Antarc* Antarctica Arctic Greenland ice core Methane hydrate |
genre_facet |
Antarc* Antarctica Arctic Greenland ice core Methane hydrate |
op_source |
http://infoscience.epfl.ch/record/298281 |
op_relation |
doi:10.1016/j.epsl.2012.06.052 http://infoscience.epfl.ch/record/298281 |
op_doi |
https://doi.org/10.1016/j.epsl.2012.06.052 |
container_title |
Earth and Planetary Science Letters |
container_volume |
349-350 |
container_start_page |
98 |
op_container_end_page |
108 |
_version_ |
1766186770787991552 |