Processes contributing to Arctic cloud dissipation and formation events that bookend clear sky periods
The Arctic is predominantly cloudy with intermittent clear sky periods. These clear periods have profound impacts on the surface energy budget and lower atmospheric stratification, connected to a lack of downwelling longwave radiation in the absence of cloud. Despite the importance of clear sky cond...
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ftcopernicus:oai:publications.copernicus.org:acpd87952 2023-05-15T14:59:47+02:00 Processes contributing to Arctic cloud dissipation and formation events that bookend clear sky periods Sedlar, Joseph Igel, Adele Telg, Hagen 2020-08-17 application/pdf https://doi.org/10.5194/acp-2020-815 https://acp.copernicus.org/preprints/acp-2020-815/ eng eng doi:10.5194/acp-2020-815 https://acp.copernicus.org/preprints/acp-2020-815/ eISSN: 1680-7324 Text 2020 ftcopernicus https://doi.org/10.5194/acp-2020-815 2020-08-24T16:22:18Z The Arctic is predominantly cloudy with intermittent clear sky periods. These clear periods have profound impacts on the surface energy budget and lower atmospheric stratification, connected to a lack of downwelling longwave radiation in the absence of cloud. Despite the importance of clear sky conditions, an understanding of the atmospheric processes leading to low-level cloud dissipation and formation events is relatively limited. A strict definition to identify clear periods at Utqiagvik (formerly Barrow), Alaska, during a five-year period (2014–2018) is developed. A suite of remote sensing and in situ instrumentation from the high-latitude observatory are analysed; we focus on comparing and contrasting atmospheric properties during low-level 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 around the clear period bookends, which suggests that a sparsity of aerosol is not frequently a cause for cloud dissipation. Further meteorological analysis indicates two active processes ongoing that appear to support the formation of low clouds after a clear sky period and have a link to surface aerosol concentrations; 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/fog layer developing near the surface. This low cloud formation is driven largely by air mass modification and pooling of aerosol particles near the surface under lower-atmosphere stratification. Text Arctic Barrow Alaska Copernicus Publications: E-Journals Arctic |
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Copernicus Publications: E-Journals |
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English |
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The Arctic is predominantly cloudy with intermittent clear sky periods. These clear periods have profound impacts on the surface energy budget and lower atmospheric stratification, connected to a lack of downwelling longwave radiation in the absence of cloud. Despite the importance of clear sky conditions, an understanding of the atmospheric processes leading to low-level cloud dissipation and formation events is relatively limited. A strict definition to identify clear periods at Utqiagvik (formerly Barrow), Alaska, during a five-year period (2014–2018) is developed. A suite of remote sensing and in situ instrumentation from the high-latitude observatory are analysed; we focus on comparing and contrasting atmospheric properties during low-level 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 around the clear period bookends, which suggests that a sparsity of aerosol is not frequently a cause for cloud dissipation. Further meteorological analysis indicates two active processes ongoing that appear to support the formation of low clouds after a clear sky period and have a link to surface aerosol concentrations; 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/fog layer developing near the surface. This low cloud formation is driven largely by air mass modification and pooling of aerosol particles near the surface under lower-atmosphere stratification. |
format |
Text |
author |
Sedlar, Joseph Igel, Adele Telg, Hagen |
spellingShingle |
Sedlar, Joseph Igel, Adele Telg, Hagen Processes contributing to Arctic cloud dissipation and formation events that bookend clear sky periods |
author_facet |
Sedlar, Joseph Igel, Adele Telg, Hagen |
author_sort |
Sedlar, Joseph |
title |
Processes contributing to Arctic cloud dissipation and formation events that bookend clear sky periods |
title_short |
Processes contributing to Arctic cloud dissipation and formation events that bookend clear sky periods |
title_full |
Processes contributing to Arctic cloud dissipation and formation events that bookend clear sky periods |
title_fullStr |
Processes contributing to Arctic cloud dissipation and formation events that bookend clear sky periods |
title_full_unstemmed |
Processes contributing to Arctic cloud dissipation and formation events that bookend clear sky periods |
title_sort |
processes contributing to arctic cloud dissipation and formation events that bookend clear sky periods |
publishDate |
2020 |
url |
https://doi.org/10.5194/acp-2020-815 https://acp.copernicus.org/preprints/acp-2020-815/ |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Barrow Alaska |
genre_facet |
Arctic Barrow Alaska |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-2020-815 https://acp.copernicus.org/preprints/acp-2020-815/ |
op_doi |
https://doi.org/10.5194/acp-2020-815 |
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1766331911188250624 |