Atmospheric conditions conducive to marine fog over the northeast Pacific in winters of 1979–2019
Observations show that the northeast Pacific (NEP) is a fog-prone area in winter compared with the northwest and central Pacific where fog rarely occurs in winter. By synthesizing observations and reanalysis results from 1979 to 2019, this study investigates the atmospheric circulation and marine at...
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ftdoajarticles:oai:doaj.org/article:0c4a53942db24b988e0df1e4ecf0dccd 2023-05-15T13:15:05+02:00 Atmospheric conditions conducive to marine fog over the northeast Pacific in winters of 1979–2019 Xinbei Li Suping Zhang Darko Koračin Li Yi Xin Zhang 2022-08-01T00:00:00Z https://doi.org/10.3389/feart.2022.942846 https://doaj.org/article/0c4a53942db24b988e0df1e4ecf0dccd EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/feart.2022.942846/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2022.942846 https://doaj.org/article/0c4a53942db24b988e0df1e4ecf0dccd Frontiers in Earth Science, Vol 10 (2022) northeast Pacific marine fog atmospheric circulation marine atmospheric boundary layer longwave radiative cooling ICOADS Science Q article 2022 ftdoajarticles https://doi.org/10.3389/feart.2022.942846 2022-12-30T21:13:32Z Observations show that the northeast Pacific (NEP) is a fog-prone area in winter compared with the northwest and central Pacific where fog rarely occurs in winter. By synthesizing observations and reanalysis results from 1979 to 2019, this study investigates the atmospheric circulation and marine atmospheric boundary layer structure associated with marine fog over the NEP in winter. Composite analysis shows that the eastern flank of the Aleutian low and the northwestern flank of the Pacific subtropical high jointly contribute to a northward air flow over the NEP. Under such conditions, warm and moist air flows through a cooler sea surface and facilitates the formation of advection-cooling fog. The air near the sea surface in foggy areas is cooled by the downward sensible heat flux. The smaller upward latent heat flux (∼10 W m−2) compared to the surrounding area (>60 W m−2) demonstrates that the moisture originates from the advection instead of local evaporation. The lower (at 925 to 875 hPa) and stronger (up to 0.08 K hPa−1) inversion layer, compared with cloudy cases and the turbulence in the lower atmosphere (below 975 hPa), also promotes fog formation and evolution. Approximately 68% of all fog cases (42242) show positive differences between surface air temperature (SAT) and sea surface temperature (SST), while 32% are negative, during southerly winds. Composite analysis of the latter shows lower specific humidity above the inversion bottom compared to the former. Dry air enhances longwave radiative cooling from the fog top, favoring cooling of the fog layer, gradually causing SAT to fall below SST. Article in Journal/Newspaper aleutian low Directory of Open Access Journals: DOAJ Articles Pacific Frontiers in Earth Science 10 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
northeast Pacific marine fog atmospheric circulation marine atmospheric boundary layer longwave radiative cooling ICOADS Science Q |
spellingShingle |
northeast Pacific marine fog atmospheric circulation marine atmospheric boundary layer longwave radiative cooling ICOADS Science Q Xinbei Li Suping Zhang Darko Koračin Li Yi Xin Zhang Atmospheric conditions conducive to marine fog over the northeast Pacific in winters of 1979–2019 |
topic_facet |
northeast Pacific marine fog atmospheric circulation marine atmospheric boundary layer longwave radiative cooling ICOADS Science Q |
description |
Observations show that the northeast Pacific (NEP) is a fog-prone area in winter compared with the northwest and central Pacific where fog rarely occurs in winter. By synthesizing observations and reanalysis results from 1979 to 2019, this study investigates the atmospheric circulation and marine atmospheric boundary layer structure associated with marine fog over the NEP in winter. Composite analysis shows that the eastern flank of the Aleutian low and the northwestern flank of the Pacific subtropical high jointly contribute to a northward air flow over the NEP. Under such conditions, warm and moist air flows through a cooler sea surface and facilitates the formation of advection-cooling fog. The air near the sea surface in foggy areas is cooled by the downward sensible heat flux. The smaller upward latent heat flux (∼10 W m−2) compared to the surrounding area (>60 W m−2) demonstrates that the moisture originates from the advection instead of local evaporation. The lower (at 925 to 875 hPa) and stronger (up to 0.08 K hPa−1) inversion layer, compared with cloudy cases and the turbulence in the lower atmosphere (below 975 hPa), also promotes fog formation and evolution. Approximately 68% of all fog cases (42242) show positive differences between surface air temperature (SAT) and sea surface temperature (SST), while 32% are negative, during southerly winds. Composite analysis of the latter shows lower specific humidity above the inversion bottom compared to the former. Dry air enhances longwave radiative cooling from the fog top, favoring cooling of the fog layer, gradually causing SAT to fall below SST. |
format |
Article in Journal/Newspaper |
author |
Xinbei Li Suping Zhang Darko Koračin Li Yi Xin Zhang |
author_facet |
Xinbei Li Suping Zhang Darko Koračin Li Yi Xin Zhang |
author_sort |
Xinbei Li |
title |
Atmospheric conditions conducive to marine fog over the northeast Pacific in winters of 1979–2019 |
title_short |
Atmospheric conditions conducive to marine fog over the northeast Pacific in winters of 1979–2019 |
title_full |
Atmospheric conditions conducive to marine fog over the northeast Pacific in winters of 1979–2019 |
title_fullStr |
Atmospheric conditions conducive to marine fog over the northeast Pacific in winters of 1979–2019 |
title_full_unstemmed |
Atmospheric conditions conducive to marine fog over the northeast Pacific in winters of 1979–2019 |
title_sort |
atmospheric conditions conducive to marine fog over the northeast pacific in winters of 1979–2019 |
publisher |
Frontiers Media S.A. |
publishDate |
2022 |
url |
https://doi.org/10.3389/feart.2022.942846 https://doaj.org/article/0c4a53942db24b988e0df1e4ecf0dccd |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
aleutian low |
genre_facet |
aleutian low |
op_source |
Frontiers in Earth Science, Vol 10 (2022) |
op_relation |
https://www.frontiersin.org/articles/10.3389/feart.2022.942846/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2022.942846 https://doaj.org/article/0c4a53942db24b988e0df1e4ecf0dccd |
op_doi |
https://doi.org/10.3389/feart.2022.942846 |
container_title |
Frontiers in Earth Science |
container_volume |
10 |
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1766266851594076160 |