Methane at Svalbard and over the European Arctic Ocean
Source at https://doi.org/10.5194/acp-18-17207-2018 . Methane (CH 4 ) is a powerful greenhouse gas. Its atmospheric mixing ratios have been increasing since 2005. Therefore, quantification of CH 4 sources is essential for effective climate change mitigation. Here we report observations of the CH 4 m...
Published in: | Atmospheric Chemistry and Physics |
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Main Authors: | , , , , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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European Geosciences Union (EGU)
2018
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Subjects: | |
Online Access: | https://hdl.handle.net/10037/14301 https://doi.org/10.5194/acp-18-17207-2018 |
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University of Tromsø: Munin Open Research Archive |
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English |
topic |
VDP::Mathematics and natural science: 400::Chemistry: 440 VDP::Matematikk og Naturvitenskap: 400::Kjemi: 440 |
spellingShingle |
VDP::Mathematics and natural science: 400::Chemistry: 440 VDP::Matematikk og Naturvitenskap: 400::Kjemi: 440 Platt, Stephen Matthew Eckhardt, Sabine Ferré, Benedicte Fisher, Rebecca E. Hermansen, Ove Jansson, Pär Lowry, David Nisbet, Euan G. Pisso, Ignacio Schmidbauer, Norbert Silyakova, Anna Stohl, Andreas Svendby, Tove Marit Vadakkepuliyambatta, Sunil Mienert, Jurgen Myhre, Cathrine Lund Methane at Svalbard and over the European Arctic Ocean |
topic_facet |
VDP::Mathematics and natural science: 400::Chemistry: 440 VDP::Matematikk og Naturvitenskap: 400::Kjemi: 440 |
description |
Source at https://doi.org/10.5194/acp-18-17207-2018 . Methane (CH 4 ) is a powerful greenhouse gas. Its atmospheric mixing ratios have been increasing since 2005. Therefore, quantification of CH 4 sources is essential for effective climate change mitigation. Here we report observations of the CH 4 mixing ratios measured at the Zeppelin Observatory (Svalbard) in the Arctic and aboard the research vessel (RV) Helmer Hanssen over the Arctic Ocean from June 2014 to December 2016, as well as the long-term CH 4 trend measured at the Zeppelin Observatory from 2001 to 2017. We investigated areas over the European Arctic Ocean to identify possible hotspot regions emitting CH 4 from the ocean to the atmosphere, and used state-of-the-art modelling (FLEXPART) combined with updated emission inventories to identify CH 4 sources. Furthermore, we collected air samples in the region as well as samples of gas hydrates, obtained from the sea floor, which we analysed using a new technique whereby hydrate gases are sampled directly into evacuated canisters. Using this new methodology, we evaluated the suitability of ethane and isotopic signatures (δ 13 C in CH 4 ) as tracers for ocean-to-atmosphere CH 4 emission. We found that the average methane / light hydrocarbon (ethane and propane) ratio is an order of magnitude higher for the same sediment samples using our new methodology compared to previously reported values, 2379.95 vs. 460.06, respectively. Meanwhile, we show that the mean atmospheric CH 4 mixing ratio in the Arctic increased by 5.9±0.38 parts per billion by volume (ppb) per year (yr −1 ) from 2001 to 2017 and ∼8 pbb yr −1 since 2008, similar to the global trend of ∼ 7–8 ppb yr −1 . Most large excursions from the baseline CH 4 mixing ratio over the European Arctic Ocean are due to long-range transport from land-based sources, lending confidence to the present inventories for high-latitude CH 4 emissions. However, we also identify a potential hotspot region with ocean–atmosphere CH 4 flux north of Svalbard (80.4∘ N, 12.8∘ E) of up to 26 nmol m −2 s −1 from a large mixing ratio increase at the location of 30 ppb. Since this flux is consistent with previous constraints (both spatially and temporally), there is no evidence that the area of interest north of Svalbard is unique in the context of the wider Arctic. Rather, because the meteorology at the time of the observation was unique in the context of the measurement time series, we obtained over the short course of the episode measurements highly sensitive to emissions over an active seep site, without sensitivity to land-based emissions. |
format |
Article in Journal/Newspaper |
author |
Platt, Stephen Matthew Eckhardt, Sabine Ferré, Benedicte Fisher, Rebecca E. Hermansen, Ove Jansson, Pär Lowry, David Nisbet, Euan G. Pisso, Ignacio Schmidbauer, Norbert Silyakova, Anna Stohl, Andreas Svendby, Tove Marit Vadakkepuliyambatta, Sunil Mienert, Jurgen Myhre, Cathrine Lund |
author_facet |
Platt, Stephen Matthew Eckhardt, Sabine Ferré, Benedicte Fisher, Rebecca E. Hermansen, Ove Jansson, Pär Lowry, David Nisbet, Euan G. Pisso, Ignacio Schmidbauer, Norbert Silyakova, Anna Stohl, Andreas Svendby, Tove Marit Vadakkepuliyambatta, Sunil Mienert, Jurgen Myhre, Cathrine Lund |
author_sort |
Platt, Stephen Matthew |
title |
Methane at Svalbard and over the European Arctic Ocean |
title_short |
Methane at Svalbard and over the European Arctic Ocean |
title_full |
Methane at Svalbard and over the European Arctic Ocean |
title_fullStr |
Methane at Svalbard and over the European Arctic Ocean |
title_full_unstemmed |
Methane at Svalbard and over the European Arctic Ocean |
title_sort |
methane at svalbard and over the european arctic ocean |
publisher |
European Geosciences Union (EGU) |
publishDate |
2018 |
url |
https://hdl.handle.net/10037/14301 https://doi.org/10.5194/acp-18-17207-2018 |
long_lat |
ENVELOPE(-164.467,-164.467,-85.983,-85.983) |
geographic |
Arctic Arctic Ocean Hanssen Svalbard |
geographic_facet |
Arctic Arctic Ocean Hanssen Svalbard |
genre |
Arctic Arctic Arctic Ocean Climate change Svalbard |
genre_facet |
Arctic Arctic Arctic Ocean Climate change Svalbard |
op_relation |
Atmospheric Chemistry and Physics info:eu-repo/grantAgreement/RCN/POLARPROG/225814/Norway/Methane Emissions from the Arctic OCean to the Atmosphere: Present and Future Climate Effects// info:eu-repo/grantAgreement/RCN/SFF/223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/ Platt, S.M., Eckhardt, S., Ferré, B., Fisher, R.E., Hermansen, O., Jansson, P., . Myhre, C.L. (2018). Methane at Svalbard and over the European Arctic Ocean. Atmospheric Chemistry and Physics , 18, 17207-17224. https://doi.org/10.5194/acp-18-17207-2018 FRIDAID 1639722 doi:10.5194/acp-18-17207-2018 1680-7316 1680-7324 https://hdl.handle.net/10037/14301 |
op_rights |
openAccess |
op_doi |
https://doi.org/10.5194/acp-18-17207-2018 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
18 |
container_issue |
23 |
container_start_page |
17207 |
op_container_end_page |
17224 |
_version_ |
1766295376792387584 |
spelling |
ftunivtroemsoe:oai:munin.uit.no:10037/14301 2023-05-15T14:22:51+02:00 Methane at Svalbard and over the European Arctic Ocean Platt, Stephen Matthew Eckhardt, Sabine Ferré, Benedicte Fisher, Rebecca E. Hermansen, Ove Jansson, Pär Lowry, David Nisbet, Euan G. Pisso, Ignacio Schmidbauer, Norbert Silyakova, Anna Stohl, Andreas Svendby, Tove Marit Vadakkepuliyambatta, Sunil Mienert, Jurgen Myhre, Cathrine Lund 2018-12-05 https://hdl.handle.net/10037/14301 https://doi.org/10.5194/acp-18-17207-2018 eng eng European Geosciences Union (EGU) Atmospheric Chemistry and Physics info:eu-repo/grantAgreement/RCN/POLARPROG/225814/Norway/Methane Emissions from the Arctic OCean to the Atmosphere: Present and Future Climate Effects// info:eu-repo/grantAgreement/RCN/SFF/223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/ Platt, S.M., Eckhardt, S., Ferré, B., Fisher, R.E., Hermansen, O., Jansson, P., . Myhre, C.L. (2018). Methane at Svalbard and over the European Arctic Ocean. Atmospheric Chemistry and Physics , 18, 17207-17224. https://doi.org/10.5194/acp-18-17207-2018 FRIDAID 1639722 doi:10.5194/acp-18-17207-2018 1680-7316 1680-7324 https://hdl.handle.net/10037/14301 openAccess VDP::Mathematics and natural science: 400::Chemistry: 440 VDP::Matematikk og Naturvitenskap: 400::Kjemi: 440 Journal article Tidsskriftartikkel Peer reviewed 2018 ftunivtroemsoe https://doi.org/10.5194/acp-18-17207-2018 2021-06-25T17:56:14Z Source at https://doi.org/10.5194/acp-18-17207-2018 . Methane (CH 4 ) is a powerful greenhouse gas. Its atmospheric mixing ratios have been increasing since 2005. Therefore, quantification of CH 4 sources is essential for effective climate change mitigation. Here we report observations of the CH 4 mixing ratios measured at the Zeppelin Observatory (Svalbard) in the Arctic and aboard the research vessel (RV) Helmer Hanssen over the Arctic Ocean from June 2014 to December 2016, as well as the long-term CH 4 trend measured at the Zeppelin Observatory from 2001 to 2017. We investigated areas over the European Arctic Ocean to identify possible hotspot regions emitting CH 4 from the ocean to the atmosphere, and used state-of-the-art modelling (FLEXPART) combined with updated emission inventories to identify CH 4 sources. Furthermore, we collected air samples in the region as well as samples of gas hydrates, obtained from the sea floor, which we analysed using a new technique whereby hydrate gases are sampled directly into evacuated canisters. Using this new methodology, we evaluated the suitability of ethane and isotopic signatures (δ 13 C in CH 4 ) as tracers for ocean-to-atmosphere CH 4 emission. We found that the average methane / light hydrocarbon (ethane and propane) ratio is an order of magnitude higher for the same sediment samples using our new methodology compared to previously reported values, 2379.95 vs. 460.06, respectively. Meanwhile, we show that the mean atmospheric CH 4 mixing ratio in the Arctic increased by 5.9±0.38 parts per billion by volume (ppb) per year (yr −1 ) from 2001 to 2017 and ∼8 pbb yr −1 since 2008, similar to the global trend of ∼ 7–8 ppb yr −1 . Most large excursions from the baseline CH 4 mixing ratio over the European Arctic Ocean are due to long-range transport from land-based sources, lending confidence to the present inventories for high-latitude CH 4 emissions. However, we also identify a potential hotspot region with ocean–atmosphere CH 4 flux north of Svalbard (80.4∘ N, 12.8∘ E) of up to 26 nmol m −2 s −1 from a large mixing ratio increase at the location of 30 ppb. Since this flux is consistent with previous constraints (both spatially and temporally), there is no evidence that the area of interest north of Svalbard is unique in the context of the wider Arctic. Rather, because the meteorology at the time of the observation was unique in the context of the measurement time series, we obtained over the short course of the episode measurements highly sensitive to emissions over an active seep site, without sensitivity to land-based emissions. Article in Journal/Newspaper Arctic Arctic Arctic Ocean Climate change Svalbard University of Tromsø: Munin Open Research Archive Arctic Arctic Ocean Hanssen ENVELOPE(-164.467,-164.467,-85.983,-85.983) Svalbard Atmospheric Chemistry and Physics 18 23 17207 17224 |