A very limited role of tropospheric chlorine as a sink of the greenhouse gas methane
Unexpectedly large seasonal phase differences between CH4 concentration and its 13C∕12C isotopic ratio and their inter-annual variations observed in southern hemispheric time series have been attributed to the Cl+CH4 reaction, in which 13CH4 is discriminated strongly compared to OH+CH4, and have pro...
Main Authors: | , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications (EGU)
2018
|
Subjects: | |
Online Access: | https://oceanrep.geomar.de/id/eprint/44207/ https://oceanrep.geomar.de/id/eprint/44207/1/acp-18-9831-2018.pdf https://oceanrep.geomar.de/id/eprint/44207/2/PalMod_Phase2_pre-proposal_20180705_final_appendixA.pdf https://doi.org/10.5194/acp-2018-188 |
id |
ftoceanrep:oai:oceanrep.geomar.de:44207 |
---|---|
record_format |
openpolar |
spelling |
ftoceanrep:oai:oceanrep.geomar.de:44207 2023-05-15T14:13:50+02:00 A very limited role of tropospheric chlorine as a sink of the greenhouse gas methane Gromov, Sergey Brenninkmeijer, Carl A. M. Jöckel, Patrick 2018 text https://oceanrep.geomar.de/id/eprint/44207/ https://oceanrep.geomar.de/id/eprint/44207/1/acp-18-9831-2018.pdf https://oceanrep.geomar.de/id/eprint/44207/2/PalMod_Phase2_pre-proposal_20180705_final_appendixA.pdf https://doi.org/10.5194/acp-2018-188 en eng Copernicus Publications (EGU) https://oceanrep.geomar.de/id/eprint/44207/1/acp-18-9831-2018.pdf https://oceanrep.geomar.de/id/eprint/44207/2/PalMod_Phase2_pre-proposal_20180705_final_appendixA.pdf Gromov, S., Brenninkmeijer, C. A. M. and Jöckel, P. (2018) A very limited role of tropospheric chlorine as a sink of the greenhouse gas methane. Open Access Atmospheric Chemistry and Physics, 18 . pp. 9831-9843. DOI 10.5194/acp-2018-188 <https://doi.org/10.5194/acp-2018-188>. doi:10.5194/acp-2018-188 cc_by_3.0 info:eu-repo/semantics/openAccess Article PeerReviewed 2018 ftoceanrep https://doi.org/10.5194/acp-2018-188 2023-04-07T15:41:11Z Unexpectedly large seasonal phase differences between CH4 concentration and its 13C∕12C isotopic ratio and their inter-annual variations observed in southern hemispheric time series have been attributed to the Cl+CH4 reaction, in which 13CH4 is discriminated strongly compared to OH+CH4, and have provided the only (indirect) evidence of a hemispheric-scale presence of oxidative cycle-relevant quantities of tropospheric atomic Cl. Our analysis of concurrent New Zealand and Antarctic time series of CH4 and CO mixing and isotope ratios shows that a corresponding 13C∕12C variability is absent in CO. Using the AC-GCM EMAC model and isotopic mass balancing for comparing the periods of presumably high and low Cl, it is shown that variations in extra-tropical Southern Hemisphere Cl cannot have exceeded 0.9 × 103atomscm−3. It is demonstrated that the 13C∕12C ratio of CO is a sensitive indicator for the isotopic composition of reacted CH4 and therefore for its sources. Despite ambiguities about the yield of CO from CH4 oxidation (with this yield being an important factor in the budget of CO) and uncertainties about the isotopic composition of sources of CO (in particular biomass burning), the contribution of Cl to the removal of CH4 in the troposphere is probably much lower than currently assumed. Article in Journal/Newspaper Antarc* Antarctic OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Antarctic New Zealand |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
Unexpectedly large seasonal phase differences between CH4 concentration and its 13C∕12C isotopic ratio and their inter-annual variations observed in southern hemispheric time series have been attributed to the Cl+CH4 reaction, in which 13CH4 is discriminated strongly compared to OH+CH4, and have provided the only (indirect) evidence of a hemispheric-scale presence of oxidative cycle-relevant quantities of tropospheric atomic Cl. Our analysis of concurrent New Zealand and Antarctic time series of CH4 and CO mixing and isotope ratios shows that a corresponding 13C∕12C variability is absent in CO. Using the AC-GCM EMAC model and isotopic mass balancing for comparing the periods of presumably high and low Cl, it is shown that variations in extra-tropical Southern Hemisphere Cl cannot have exceeded 0.9 × 103atomscm−3. It is demonstrated that the 13C∕12C ratio of CO is a sensitive indicator for the isotopic composition of reacted CH4 and therefore for its sources. Despite ambiguities about the yield of CO from CH4 oxidation (with this yield being an important factor in the budget of CO) and uncertainties about the isotopic composition of sources of CO (in particular biomass burning), the contribution of Cl to the removal of CH4 in the troposphere is probably much lower than currently assumed. |
format |
Article in Journal/Newspaper |
author |
Gromov, Sergey Brenninkmeijer, Carl A. M. Jöckel, Patrick |
spellingShingle |
Gromov, Sergey Brenninkmeijer, Carl A. M. Jöckel, Patrick A very limited role of tropospheric chlorine as a sink of the greenhouse gas methane |
author_facet |
Gromov, Sergey Brenninkmeijer, Carl A. M. Jöckel, Patrick |
author_sort |
Gromov, Sergey |
title |
A very limited role of tropospheric chlorine as a sink of the greenhouse gas methane |
title_short |
A very limited role of tropospheric chlorine as a sink of the greenhouse gas methane |
title_full |
A very limited role of tropospheric chlorine as a sink of the greenhouse gas methane |
title_fullStr |
A very limited role of tropospheric chlorine as a sink of the greenhouse gas methane |
title_full_unstemmed |
A very limited role of tropospheric chlorine as a sink of the greenhouse gas methane |
title_sort |
very limited role of tropospheric chlorine as a sink of the greenhouse gas methane |
publisher |
Copernicus Publications (EGU) |
publishDate |
2018 |
url |
https://oceanrep.geomar.de/id/eprint/44207/ https://oceanrep.geomar.de/id/eprint/44207/1/acp-18-9831-2018.pdf https://oceanrep.geomar.de/id/eprint/44207/2/PalMod_Phase2_pre-proposal_20180705_final_appendixA.pdf https://doi.org/10.5194/acp-2018-188 |
geographic |
Antarctic New Zealand |
geographic_facet |
Antarctic New Zealand |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
https://oceanrep.geomar.de/id/eprint/44207/1/acp-18-9831-2018.pdf https://oceanrep.geomar.de/id/eprint/44207/2/PalMod_Phase2_pre-proposal_20180705_final_appendixA.pdf Gromov, S., Brenninkmeijer, C. A. M. and Jöckel, P. (2018) A very limited role of tropospheric chlorine as a sink of the greenhouse gas methane. Open Access Atmospheric Chemistry and Physics, 18 . pp. 9831-9843. DOI 10.5194/acp-2018-188 <https://doi.org/10.5194/acp-2018-188>. doi:10.5194/acp-2018-188 |
op_rights |
cc_by_3.0 info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/acp-2018-188 |
_version_ |
1766286369891549184 |