Ten-year chemical signatures associated with long-range transport observed in the free troposphere over the central North Atlantic
Ten-year observations of trace gases at Pico Mountain Observatory (PMO), a free troposphere site in the central North Atlantic, were classified by transport patterns using the Lagrangian particle dispersion model, FLEXPART. The classification enabled identifying trace gas mixing ratios associated wi...
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ftdoajarticles:oai:doaj.org/article:865005d01d0446d8833a0ee075072da7 2023-05-15T17:30:43+02:00 Ten-year chemical signatures associated with long-range transport observed in the free troposphere over the central North Atlantic B. Zhang R. C. Owen J. A. Perlinger D. Helmig M. Val Martín L. Kramer L. R. Mazzoleni C. Mazzoleni 2017-03-01T00:00:00Z https://doi.org/10.1525/elementa.194 https://doaj.org/article/865005d01d0446d8833a0ee075072da7 EN eng BioOne https://www.elementascience.org/articles/194 https://doaj.org/toc/2325-1026 2325-1026 doi:10.1525/elementa.194 https://doaj.org/article/865005d01d0446d8833a0ee075072da7 Elementa: Science of the Anthropocene, Vol 5 (2017) Long-range transport patterns to Azores Long-term observations of ozone and ozone precursors Non-methane hydrocarbon aging Environmental sciences GE1-350 article 2017 ftdoajarticles https://doi.org/10.1525/elementa.194 2022-12-31T14:06:31Z Ten-year observations of trace gases at Pico Mountain Observatory (PMO), a free troposphere site in the central North Atlantic, were classified by transport patterns using the Lagrangian particle dispersion model, FLEXPART. The classification enabled identifying trace gas mixing ratios associated with background air and long- range transport of continental emissions, which were defined as chemical signatures. Comparison between the chemical signatures revealed the impacts of natural and anthropogenic sources, as well as chemical and physical processes during long transport, on air composition in the remote North Atlantic. Transport of North American anthropogenic emissions (NA-Anthro) and summertime wildfire plumes (Fire) significantly enhanced CO and O3 at PMO. Summertime CO enhancements caused by NA-Anthro were found to have been decreasing by a rate of 0.67 ± 0.60 ppbv/year in the ten-year period, due possibly to reduction of emissions in North America. Downward mixing from the upper troposphere and stratosphere due to the persistent Azores-Bermuda anticyclone causes enhanced O3 and nitrogen oxides. The 'd' [O3]/'d' [CO] value was used to investigate O3 sources and chemistry in different transport patterns. The transport pattern affected by Fire had the lowest 'd' [O3]/'d' [CO], which was likely due to intense CO production and depressed O3 production in wildfire plumes. Slightly enhanced O3 and 'd' [O3]/'d' [CO] were found in the background air, suggesting that weak downward mixing from the upper troposphere is common at PMO. Enhancements of both butane isomers were found during upslope flow periods, indicating contributions from local sources. The consistent ratio of butane isomers associated with the background air and NA-anthro implies no clear difference in the oxidation rates of the butane isomers during long transport. Based on observed relationships between non-methane hydrocarbons, the averaged photochemical age of the air masses at PMO was estimated to be 11 ± 4 days. Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Elementa: Science of the Anthropocene 5 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Long-range transport patterns to Azores Long-term observations of ozone and ozone precursors Non-methane hydrocarbon aging Environmental sciences GE1-350 |
spellingShingle |
Long-range transport patterns to Azores Long-term observations of ozone and ozone precursors Non-methane hydrocarbon aging Environmental sciences GE1-350 B. Zhang R. C. Owen J. A. Perlinger D. Helmig M. Val Martín L. Kramer L. R. Mazzoleni C. Mazzoleni Ten-year chemical signatures associated with long-range transport observed in the free troposphere over the central North Atlantic |
topic_facet |
Long-range transport patterns to Azores Long-term observations of ozone and ozone precursors Non-methane hydrocarbon aging Environmental sciences GE1-350 |
description |
Ten-year observations of trace gases at Pico Mountain Observatory (PMO), a free troposphere site in the central North Atlantic, were classified by transport patterns using the Lagrangian particle dispersion model, FLEXPART. The classification enabled identifying trace gas mixing ratios associated with background air and long- range transport of continental emissions, which were defined as chemical signatures. Comparison between the chemical signatures revealed the impacts of natural and anthropogenic sources, as well as chemical and physical processes during long transport, on air composition in the remote North Atlantic. Transport of North American anthropogenic emissions (NA-Anthro) and summertime wildfire plumes (Fire) significantly enhanced CO and O3 at PMO. Summertime CO enhancements caused by NA-Anthro were found to have been decreasing by a rate of 0.67 ± 0.60 ppbv/year in the ten-year period, due possibly to reduction of emissions in North America. Downward mixing from the upper troposphere and stratosphere due to the persistent Azores-Bermuda anticyclone causes enhanced O3 and nitrogen oxides. The 'd' [O3]/'d' [CO] value was used to investigate O3 sources and chemistry in different transport patterns. The transport pattern affected by Fire had the lowest 'd' [O3]/'d' [CO], which was likely due to intense CO production and depressed O3 production in wildfire plumes. Slightly enhanced O3 and 'd' [O3]/'d' [CO] were found in the background air, suggesting that weak downward mixing from the upper troposphere is common at PMO. Enhancements of both butane isomers were found during upslope flow periods, indicating contributions from local sources. The consistent ratio of butane isomers associated with the background air and NA-anthro implies no clear difference in the oxidation rates of the butane isomers during long transport. Based on observed relationships between non-methane hydrocarbons, the averaged photochemical age of the air masses at PMO was estimated to be 11 ± 4 days. |
format |
Article in Journal/Newspaper |
author |
B. Zhang R. C. Owen J. A. Perlinger D. Helmig M. Val Martín L. Kramer L. R. Mazzoleni C. Mazzoleni |
author_facet |
B. Zhang R. C. Owen J. A. Perlinger D. Helmig M. Val Martín L. Kramer L. R. Mazzoleni C. Mazzoleni |
author_sort |
B. Zhang |
title |
Ten-year chemical signatures associated with long-range transport observed in the free troposphere over the central North Atlantic |
title_short |
Ten-year chemical signatures associated with long-range transport observed in the free troposphere over the central North Atlantic |
title_full |
Ten-year chemical signatures associated with long-range transport observed in the free troposphere over the central North Atlantic |
title_fullStr |
Ten-year chemical signatures associated with long-range transport observed in the free troposphere over the central North Atlantic |
title_full_unstemmed |
Ten-year chemical signatures associated with long-range transport observed in the free troposphere over the central North Atlantic |
title_sort |
ten-year chemical signatures associated with long-range transport observed in the free troposphere over the central north atlantic |
publisher |
BioOne |
publishDate |
2017 |
url |
https://doi.org/10.1525/elementa.194 https://doaj.org/article/865005d01d0446d8833a0ee075072da7 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Elementa: Science of the Anthropocene, Vol 5 (2017) |
op_relation |
https://www.elementascience.org/articles/194 https://doaj.org/toc/2325-1026 2325-1026 doi:10.1525/elementa.194 https://doaj.org/article/865005d01d0446d8833a0ee075072da7 |
op_doi |
https://doi.org/10.1525/elementa.194 |
container_title |
Elementa: Science of the Anthropocene |
container_volume |
5 |
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1766127613339762688 |