Methane flux estimates from continuous atmospheric measurements and surface-water observations in the northern Labrador Sea and Baffin Bay
Vast amounts of methane (CH 4 ) stored in permafrost and submarine sediments are susceptible to release in a warming Arctic, further exacerbating climate change in a positive feedback. It is therefore critical to monitor CH 4 over pan-regional scales to detect early signs of CH 4 release. However, o...
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ftcopernicus:oai:publications.copernicus.org:egusphere104797 2023-05-15T15:17:22+02:00 Methane flux estimates from continuous atmospheric measurements and surface-water observations in the northern Labrador Sea and Baffin Bay Vogt, Judith Risk, David Azetsu-Scott, Kumiko Edinger, Evan N. Sherwood, Owen A. 2022-07-12 application/pdf https://doi.org/10.5194/egusphere-2022-545 https://egusphere.copernicus.org/preprints/2022/egusphere-2022-545/ eng eng doi:10.5194/egusphere-2022-545 https://egusphere.copernicus.org/preprints/2022/egusphere-2022-545/ eISSN: Text 2022 ftcopernicus https://doi.org/10.5194/egusphere-2022-545 2022-07-25T16:22:43Z Vast amounts of methane (CH 4 ) stored in permafrost and submarine sediments are susceptible to release in a warming Arctic, further exacerbating climate change in a positive feedback. It is therefore critical to monitor CH 4 over pan-regional scales to detect early signs of CH 4 release. However, our ability to monitor CH 4 is hampered in remote northern regions by sampling and logistical constraints and few good baseline data exist in many areas. To create a baseline study of current background levels of CH 4 in North Atlantic waters, we collected continuous real-time atmospheric CH 4 data, along with ambient air temperature and wind parameters over 22 days in summer 2021 on a roughly 5100 km voyage in the northern Labrador Sea and Baffin Bay up to 71° N. In addition, we measured CH 4 concentrations in the water column using discrete water samples at selected stations. Measured atmospheric mixing ratios of CH 4 ranged from 1944.7 ppb to 2012.0 ppb, with a mean of 1966.0±7.4 ppb and a baseline of 1954.2−1980.6 ppb. Dissolved CH 4 concentrations in the near-surface water peaked at 56.58±0.05 nM within 1 km down-current of a known cold seep at Scott Inlet but were consistently super-saturated throughout the water column in Southwind Fjord, which is an area recently affected by submarine landslides. Local sea-air CH 4 fluxes ranged from 0.1−14.1 µmol m -2 d -1 indicating that the ocean acted as a CH 4 source to the atmosphere. Atmospheric CH 4 levels were also driven by meteorological, spatial, and temporal variations. Highest atmospheric CH 4 mixing ratios were detected in the Cumberland Sound in Nunavut, suggesting onshore sources from nearby waterbodies and wetlands, whereas ocean-based contributions at this location could not be ruled out. Coupled real-time measurements of marine and atmospheric CH 4 data have the potential to provide ongoing monitoring in a region susceptible to CH 4 releases, as well as critical validation data for global-scale measurements and modelling. Text Arctic Baffin Bay Baffin Bay Baffin Climate change Cumberland Sound Labrador Sea North Atlantic Nunavut permafrost Copernicus Publications: E-Journals Arctic Baffin Bay Cumberland Sound ENVELOPE(-66.014,-66.014,65.334,65.334) Nunavut |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Vast amounts of methane (CH 4 ) stored in permafrost and submarine sediments are susceptible to release in a warming Arctic, further exacerbating climate change in a positive feedback. It is therefore critical to monitor CH 4 over pan-regional scales to detect early signs of CH 4 release. However, our ability to monitor CH 4 is hampered in remote northern regions by sampling and logistical constraints and few good baseline data exist in many areas. To create a baseline study of current background levels of CH 4 in North Atlantic waters, we collected continuous real-time atmospheric CH 4 data, along with ambient air temperature and wind parameters over 22 days in summer 2021 on a roughly 5100 km voyage in the northern Labrador Sea and Baffin Bay up to 71° N. In addition, we measured CH 4 concentrations in the water column using discrete water samples at selected stations. Measured atmospheric mixing ratios of CH 4 ranged from 1944.7 ppb to 2012.0 ppb, with a mean of 1966.0±7.4 ppb and a baseline of 1954.2−1980.6 ppb. Dissolved CH 4 concentrations in the near-surface water peaked at 56.58±0.05 nM within 1 km down-current of a known cold seep at Scott Inlet but were consistently super-saturated throughout the water column in Southwind Fjord, which is an area recently affected by submarine landslides. Local sea-air CH 4 fluxes ranged from 0.1−14.1 µmol m -2 d -1 indicating that the ocean acted as a CH 4 source to the atmosphere. Atmospheric CH 4 levels were also driven by meteorological, spatial, and temporal variations. Highest atmospheric CH 4 mixing ratios were detected in the Cumberland Sound in Nunavut, suggesting onshore sources from nearby waterbodies and wetlands, whereas ocean-based contributions at this location could not be ruled out. Coupled real-time measurements of marine and atmospheric CH 4 data have the potential to provide ongoing monitoring in a region susceptible to CH 4 releases, as well as critical validation data for global-scale measurements and modelling. |
format |
Text |
author |
Vogt, Judith Risk, David Azetsu-Scott, Kumiko Edinger, Evan N. Sherwood, Owen A. |
spellingShingle |
Vogt, Judith Risk, David Azetsu-Scott, Kumiko Edinger, Evan N. Sherwood, Owen A. Methane flux estimates from continuous atmospheric measurements and surface-water observations in the northern Labrador Sea and Baffin Bay |
author_facet |
Vogt, Judith Risk, David Azetsu-Scott, Kumiko Edinger, Evan N. Sherwood, Owen A. |
author_sort |
Vogt, Judith |
title |
Methane flux estimates from continuous atmospheric measurements and surface-water observations in the northern Labrador Sea and Baffin Bay |
title_short |
Methane flux estimates from continuous atmospheric measurements and surface-water observations in the northern Labrador Sea and Baffin Bay |
title_full |
Methane flux estimates from continuous atmospheric measurements and surface-water observations in the northern Labrador Sea and Baffin Bay |
title_fullStr |
Methane flux estimates from continuous atmospheric measurements and surface-water observations in the northern Labrador Sea and Baffin Bay |
title_full_unstemmed |
Methane flux estimates from continuous atmospheric measurements and surface-water observations in the northern Labrador Sea and Baffin Bay |
title_sort |
methane flux estimates from continuous atmospheric measurements and surface-water observations in the northern labrador sea and baffin bay |
publishDate |
2022 |
url |
https://doi.org/10.5194/egusphere-2022-545 https://egusphere.copernicus.org/preprints/2022/egusphere-2022-545/ |
long_lat |
ENVELOPE(-66.014,-66.014,65.334,65.334) |
geographic |
Arctic Baffin Bay Cumberland Sound Nunavut |
geographic_facet |
Arctic Baffin Bay Cumberland Sound Nunavut |
genre |
Arctic Baffin Bay Baffin Bay Baffin Climate change Cumberland Sound Labrador Sea North Atlantic Nunavut permafrost |
genre_facet |
Arctic Baffin Bay Baffin Bay Baffin Climate change Cumberland Sound Labrador Sea North Atlantic Nunavut permafrost |
op_source |
eISSN: |
op_relation |
doi:10.5194/egusphere-2022-545 https://egusphere.copernicus.org/preprints/2022/egusphere-2022-545/ |
op_doi |
https://doi.org/10.5194/egusphere-2022-545 |
_version_ |
1766347616581320704 |