Processes contributing to cloud dissipation and formation events on the North Slope of Alaska
Clear-sky periods across the high latitudes have profound impacts on the surface energy budget and lower atmospheric stratification; however an understanding of the atmospheric processes leading to low-level cloud dissipation and formation events is limited. A method to identify clear periods at Utq...
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ftcopernicus:oai:publications.copernicus.org:acp87952 2023-05-15T15:39:41+02:00 Processes contributing to cloud dissipation and formation events on the North Slope of Alaska Sedlar, Joseph Igel, Adele Telg, Hagen 2021-03-18 application/pdf https://doi.org/10.5194/acp-21-4149-2021 https://acp.copernicus.org/articles/21/4149/2021/ eng eng doi:10.5194/acp-21-4149-2021 https://acp.copernicus.org/articles/21/4149/2021/ eISSN: 1680-7324 Text 2021 ftcopernicus https://doi.org/10.5194/acp-21-4149-2021 2021-03-22T17:22:14Z Clear-sky periods across the high latitudes have profound impacts on the surface energy budget and lower atmospheric stratification; however an understanding of the atmospheric processes leading to low-level cloud dissipation and formation events is limited. A method to identify clear periods at Utqiaġvik (formerly Barrow), Alaska, during a 5-year period (2014–2018) is developed. A suite of remote sensing and in situ measurements from the high-latitude observatory are analyzed; we focus on comparing and contrasting atmospheric properties during low-level (below 2 km ) cloud dissipation and formation events to understand the processes controlling clear-sky periods. Vertical profiles of lidar backscatter suggest that aerosol presence across the lower atmosphere is relatively invariant during the periods bookending clear conditions, which suggests that a sparsity of aerosol is not frequently a cause for cloud dissipation on the North Slope of Alaska. Further, meteorological analysis indicates two active processes ongoing that appear to support the formation of low clouds after a clear-sky period: namely, horizontal advection, which was dominant in winter and early spring, and quiescent air mass modification, which was dominant in the summer. During summer, the dominant mode of cloud formation is a low cloud or fog layer developing near the surface. This low cloud formation is driven largely by air mass modification under relatively quiescent synoptic conditions. Near-surface aerosol particles concentrations changed by a factor of 2 around summer formation events. Thermodynamic adjustment and increased aerosol presence under quiescent atmospheric conditions are hypothesized as important mechanisms for fog formation. Text Barrow north slope Alaska Copernicus Publications: E-Journals Atmospheric Chemistry and Physics 21 5 4149 4167 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Clear-sky periods across the high latitudes have profound impacts on the surface energy budget and lower atmospheric stratification; however an understanding of the atmospheric processes leading to low-level cloud dissipation and formation events is limited. A method to identify clear periods at Utqiaġvik (formerly Barrow), Alaska, during a 5-year period (2014–2018) is developed. A suite of remote sensing and in situ measurements from the high-latitude observatory are analyzed; we focus on comparing and contrasting atmospheric properties during low-level (below 2 km ) cloud dissipation and formation events to understand the processes controlling clear-sky periods. Vertical profiles of lidar backscatter suggest that aerosol presence across the lower atmosphere is relatively invariant during the periods bookending clear conditions, which suggests that a sparsity of aerosol is not frequently a cause for cloud dissipation on the North Slope of Alaska. Further, meteorological analysis indicates two active processes ongoing that appear to support the formation of low clouds after a clear-sky period: namely, horizontal advection, which was dominant in winter and early spring, and quiescent air mass modification, which was dominant in the summer. During summer, the dominant mode of cloud formation is a low cloud or fog layer developing near the surface. This low cloud formation is driven largely by air mass modification under relatively quiescent synoptic conditions. Near-surface aerosol particles concentrations changed by a factor of 2 around summer formation events. Thermodynamic adjustment and increased aerosol presence under quiescent atmospheric conditions are hypothesized as important mechanisms for fog formation. |
format |
Text |
author |
Sedlar, Joseph Igel, Adele Telg, Hagen |
spellingShingle |
Sedlar, Joseph Igel, Adele Telg, Hagen Processes contributing to cloud dissipation and formation events on the North Slope of Alaska |
author_facet |
Sedlar, Joseph Igel, Adele Telg, Hagen |
author_sort |
Sedlar, Joseph |
title |
Processes contributing to cloud dissipation and formation events on the North Slope of Alaska |
title_short |
Processes contributing to cloud dissipation and formation events on the North Slope of Alaska |
title_full |
Processes contributing to cloud dissipation and formation events on the North Slope of Alaska |
title_fullStr |
Processes contributing to cloud dissipation and formation events on the North Slope of Alaska |
title_full_unstemmed |
Processes contributing to cloud dissipation and formation events on the North Slope of Alaska |
title_sort |
processes contributing to cloud dissipation and formation events on the north slope of alaska |
publishDate |
2021 |
url |
https://doi.org/10.5194/acp-21-4149-2021 https://acp.copernicus.org/articles/21/4149/2021/ |
genre |
Barrow north slope Alaska |
genre_facet |
Barrow north slope Alaska |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-21-4149-2021 https://acp.copernicus.org/articles/21/4149/2021/ |
op_doi |
https://doi.org/10.5194/acp-21-4149-2021 |
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Atmospheric Chemistry and Physics |
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21 |
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5 |
container_start_page |
4149 |
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4167 |
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1766371722357899264 |