Central Arctic Ocean surface–atmosphere exchange of CO2 and CH4 constrained by direct measurements
The central Arctic Ocean (CAO) plays an important role in the global carbon cycle, but the current and future exchange of the climate-forcing trace gases methane(CH4) and carbon dioxide (CO2) between the CAO and the atmosphere is highly uncertain. In particular, there are very few observations of ne...
Published in: | Biogeosciences |
---|---|
Main Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2024
|
Subjects: | |
Online Access: | https://plymsea.ac.uk/id/eprint/10184/ https://plymsea.ac.uk/id/eprint/10184/1/Prytherch%202024.%20Central%20Arctic%20Ocean%20surface%E2%80%93atmosphere%20exchange%20of%20CO2%20and%20CH4%20constrained%20by%20direct%20measurements.pdf https://doi.org/10.5194/bg-21-671-2024 |
id |
ftplymouthml:oai:plymsea.ac.uk:10184 |
---|---|
record_format |
openpolar |
spelling |
ftplymouthml:oai:plymsea.ac.uk:10184 2024-05-19T07:33:23+00:00 Central Arctic Ocean surface–atmosphere exchange of CO2 and CH4 constrained by direct measurements Prytherch, J Murto, S Brown, IJ Ulfsbo, A Thornton, BF Brüchert, V Tjernström, M Hermansson, AL Nylund, AT Holthusen, LA 2024-02-02 text https://plymsea.ac.uk/id/eprint/10184/ https://plymsea.ac.uk/id/eprint/10184/1/Prytherch%202024.%20Central%20Arctic%20Ocean%20surface%E2%80%93atmosphere%20exchange%20of%20CO2%20and%20CH4%20constrained%20by%20direct%20measurements.pdf https://doi.org/10.5194/bg-21-671-2024 en eng Copernicus Publications https://plymsea.ac.uk/id/eprint/10184/1/Prytherch%202024.%20Central%20Arctic%20Ocean%20surface%E2%80%93atmosphere%20exchange%20of%20CO2%20and%20CH4%20constrained%20by%20direct%20measurements.pdf Prytherch, J, Murto, S, Brown, IJ, Ulfsbo, A, Thornton, BF, Brüchert, V, Tjernström, M, Hermansson, AL, Nylund, AT and Holthusen, LA 2024 Central Arctic Ocean surface–atmosphere exchange of CO2 and CH4 constrained by direct measurements. Biogeosciences, 21 (2). 671-688. https://doi.org/10.5194/bg-21-671-2024 <https://doi.org/10.5194/bg-21-671-2024> cc_by_4 Publication - Article PeerReviewed 2024 ftplymouthml https://doi.org/10.5194/bg-21-671-2024 2024-04-24T00:15:11Z The central Arctic Ocean (CAO) plays an important role in the global carbon cycle, but the current and future exchange of the climate-forcing trace gases methane(CH4) and carbon dioxide (CO2) between the CAO and the atmosphere is highly uncertain. In particular, there are very few observations of near-surface gas concentrations or direct air–sea CO2 flux estimates and no previously reported direct air–sea CH4 flux estimates from the CAO. Furthermore, the effect of sea ice on the exchange is not well understood. We present direct measurements of the air–sea flux of CH4 and CO2, as well as air–snow fluxes of CO2 in the summertime CAO north of 82.5◦ N from the Synoptic Arctic Survey (SAS) expedition carried out on the Swedish icebreaker Oden in 2021. Measurements of air–sea CH4 and CO2 flux were made using floating chambers deployed in leads accessed from sea ice and from the side of Oden, and air–snow fluxes were determined from chambers deployed on sea ice. Gas transfer velocities determined from fluxes and surface-water-dissolved gas concentrations exhibited a weaker wind speed dependence than existing parameterisations, with a median sea-ice lead gas transfer rate of 2.5 cm h−1 applicable over the observed 10 m wind speed range (1–11 m s−1 ). The average observed air–sea CO2 flux was −7.6 mmolm−2 d −1, and the average air–snow CO2 flux was −1.1 mmolm−2 d −1. Extrapolating these fluxes and the corresponding sea-ice concentrations gives an August and September flux for the CAO of −1.75 mmolm−2 d −1, within the range of previous indirect estimates.The average observed air–sea CH4 flux of 3.5 µmolm−2 d−1, accounting for sea-ice concentration, equates to an August and September CAO flux of 0.35 µmolm−2 d−1, lower than previous estimates and implying that the CAO is a very small (- 1 %) contributor to the Arctic flux of CH4 to the atmosphere. Article in Journal/Newspaper Arctic Arctic Arctic Ocean oden Sea ice Plymouth Marine Science Electronic Archive (PlyMSEA - Plymouth Marine Laboratory, PML) Biogeosciences 21 2 671 688 |
institution |
Open Polar |
collection |
Plymouth Marine Science Electronic Archive (PlyMSEA - Plymouth Marine Laboratory, PML) |
op_collection_id |
ftplymouthml |
language |
English |
description |
The central Arctic Ocean (CAO) plays an important role in the global carbon cycle, but the current and future exchange of the climate-forcing trace gases methane(CH4) and carbon dioxide (CO2) between the CAO and the atmosphere is highly uncertain. In particular, there are very few observations of near-surface gas concentrations or direct air–sea CO2 flux estimates and no previously reported direct air–sea CH4 flux estimates from the CAO. Furthermore, the effect of sea ice on the exchange is not well understood. We present direct measurements of the air–sea flux of CH4 and CO2, as well as air–snow fluxes of CO2 in the summertime CAO north of 82.5◦ N from the Synoptic Arctic Survey (SAS) expedition carried out on the Swedish icebreaker Oden in 2021. Measurements of air–sea CH4 and CO2 flux were made using floating chambers deployed in leads accessed from sea ice and from the side of Oden, and air–snow fluxes were determined from chambers deployed on sea ice. Gas transfer velocities determined from fluxes and surface-water-dissolved gas concentrations exhibited a weaker wind speed dependence than existing parameterisations, with a median sea-ice lead gas transfer rate of 2.5 cm h−1 applicable over the observed 10 m wind speed range (1–11 m s−1 ). The average observed air–sea CO2 flux was −7.6 mmolm−2 d −1, and the average air–snow CO2 flux was −1.1 mmolm−2 d −1. Extrapolating these fluxes and the corresponding sea-ice concentrations gives an August and September flux for the CAO of −1.75 mmolm−2 d −1, within the range of previous indirect estimates.The average observed air–sea CH4 flux of 3.5 µmolm−2 d−1, accounting for sea-ice concentration, equates to an August and September CAO flux of 0.35 µmolm−2 d−1, lower than previous estimates and implying that the CAO is a very small (- 1 %) contributor to the Arctic flux of CH4 to the atmosphere. |
format |
Article in Journal/Newspaper |
author |
Prytherch, J Murto, S Brown, IJ Ulfsbo, A Thornton, BF Brüchert, V Tjernström, M Hermansson, AL Nylund, AT Holthusen, LA |
spellingShingle |
Prytherch, J Murto, S Brown, IJ Ulfsbo, A Thornton, BF Brüchert, V Tjernström, M Hermansson, AL Nylund, AT Holthusen, LA Central Arctic Ocean surface–atmosphere exchange of CO2 and CH4 constrained by direct measurements |
author_facet |
Prytherch, J Murto, S Brown, IJ Ulfsbo, A Thornton, BF Brüchert, V Tjernström, M Hermansson, AL Nylund, AT Holthusen, LA |
author_sort |
Prytherch, J |
title |
Central Arctic Ocean surface–atmosphere exchange of CO2 and CH4 constrained by direct measurements |
title_short |
Central Arctic Ocean surface–atmosphere exchange of CO2 and CH4 constrained by direct measurements |
title_full |
Central Arctic Ocean surface–atmosphere exchange of CO2 and CH4 constrained by direct measurements |
title_fullStr |
Central Arctic Ocean surface–atmosphere exchange of CO2 and CH4 constrained by direct measurements |
title_full_unstemmed |
Central Arctic Ocean surface–atmosphere exchange of CO2 and CH4 constrained by direct measurements |
title_sort |
central arctic ocean surface–atmosphere exchange of co2 and ch4 constrained by direct measurements |
publisher |
Copernicus Publications |
publishDate |
2024 |
url |
https://plymsea.ac.uk/id/eprint/10184/ https://plymsea.ac.uk/id/eprint/10184/1/Prytherch%202024.%20Central%20Arctic%20Ocean%20surface%E2%80%93atmosphere%20exchange%20of%20CO2%20and%20CH4%20constrained%20by%20direct%20measurements.pdf https://doi.org/10.5194/bg-21-671-2024 |
genre |
Arctic Arctic Arctic Ocean oden Sea ice |
genre_facet |
Arctic Arctic Arctic Ocean oden Sea ice |
op_relation |
https://plymsea.ac.uk/id/eprint/10184/1/Prytherch%202024.%20Central%20Arctic%20Ocean%20surface%E2%80%93atmosphere%20exchange%20of%20CO2%20and%20CH4%20constrained%20by%20direct%20measurements.pdf Prytherch, J, Murto, S, Brown, IJ, Ulfsbo, A, Thornton, BF, Brüchert, V, Tjernström, M, Hermansson, AL, Nylund, AT and Holthusen, LA 2024 Central Arctic Ocean surface–atmosphere exchange of CO2 and CH4 constrained by direct measurements. Biogeosciences, 21 (2). 671-688. https://doi.org/10.5194/bg-21-671-2024 <https://doi.org/10.5194/bg-21-671-2024> |
op_rights |
cc_by_4 |
op_doi |
https://doi.org/10.5194/bg-21-671-2024 |
container_title |
Biogeosciences |
container_volume |
21 |
container_issue |
2 |
container_start_page |
671 |
op_container_end_page |
688 |
_version_ |
1799471445678489600 |