Formation of maritime convergence zones within cold air outbreaks due to the shape of the coastline or sea ice edge
Maritime cold air outbreaks often feature convergence zones that provide a conducive environment for the development of polar mesoscale cyclones and polar lows. This study examines the formation mechanisms of these convergence zones in cold air outbreaks downstream of a coastline or sea-ice edge. A...
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Online Access: | https://hdl.handle.net/11250/3062099 https://doi.org/10.1002/qj.4324 |
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ftunivbergen:oai:bora.uib.no:11250/3062099 2023-05-15T18:17:26+02:00 Formation of maritime convergence zones within cold air outbreaks due to the shape of the coastline or sea ice edge Watanabe, Shun-ichi I. Niino, Hiroshi Spengler, Thomas 2022 application/pdf https://hdl.handle.net/11250/3062099 https://doi.org/10.1002/qj.4324 eng eng Wiley urn:issn:0035-9009 https://hdl.handle.net/11250/3062099 https://doi.org/10.1002/qj.4324 cristin:2055388 Quarterly Journal of the Royal Meteorological Society. 2022, 148 (746), 2546-2562. Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no Copyright 2022 The Author(s) Quarterly Journal of the Royal Meteorological Society 2546-2562 148 746 Journal article Peer reviewed 2022 ftunivbergen https://doi.org/10.1002/qj.4324 2023-04-05T23:05:50Z Maritime cold air outbreaks often feature convergence zones that provide a conducive environment for the development of polar mesoscale cyclones and polar lows. This study examines the formation mechanisms of these convergence zones in cold air outbreaks downstream of a coastline or sea-ice edge. A simplified configuration in which the coastline or sea-ice edge is approximated by a line featuring a bend with an angle is examined using analytic solutions and idealised numerical simulations. The bend of the coastline causes differences in the fetch over which air parcels travel, causing a warm wedge of air downstream of the bend due to differential airmass transformations. The warm wedge is associated with a pressure trough that leads to convergence in the presence of surface friction. The analytic model captures this mechanism and compares well with the idealised numerical simulations. Condensational heating associated with moist convection enhances vertical motions and thus intensifies the horizontal convergence. The idealised numerical simulations also reproduce an asymmetry in the vertical shear of the horizontal wind across the convergence zone, which explains the transverse cloud streets downstream to the left of the convergence zone. publishedVersion Article in Journal/Newspaper Sea ice University of Bergen: Bergen Open Research Archive (BORA-UiB) Quarterly Journal of the Royal Meteorological Society 148 746 2546 2562 |
institution |
Open Polar |
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University of Bergen: Bergen Open Research Archive (BORA-UiB) |
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ftunivbergen |
language |
English |
description |
Maritime cold air outbreaks often feature convergence zones that provide a conducive environment for the development of polar mesoscale cyclones and polar lows. This study examines the formation mechanisms of these convergence zones in cold air outbreaks downstream of a coastline or sea-ice edge. A simplified configuration in which the coastline or sea-ice edge is approximated by a line featuring a bend with an angle is examined using analytic solutions and idealised numerical simulations. The bend of the coastline causes differences in the fetch over which air parcels travel, causing a warm wedge of air downstream of the bend due to differential airmass transformations. The warm wedge is associated with a pressure trough that leads to convergence in the presence of surface friction. The analytic model captures this mechanism and compares well with the idealised numerical simulations. Condensational heating associated with moist convection enhances vertical motions and thus intensifies the horizontal convergence. The idealised numerical simulations also reproduce an asymmetry in the vertical shear of the horizontal wind across the convergence zone, which explains the transverse cloud streets downstream to the left of the convergence zone. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Watanabe, Shun-ichi I. Niino, Hiroshi Spengler, Thomas |
spellingShingle |
Watanabe, Shun-ichi I. Niino, Hiroshi Spengler, Thomas Formation of maritime convergence zones within cold air outbreaks due to the shape of the coastline or sea ice edge |
author_facet |
Watanabe, Shun-ichi I. Niino, Hiroshi Spengler, Thomas |
author_sort |
Watanabe, Shun-ichi I. |
title |
Formation of maritime convergence zones within cold air outbreaks due to the shape of the coastline or sea ice edge |
title_short |
Formation of maritime convergence zones within cold air outbreaks due to the shape of the coastline or sea ice edge |
title_full |
Formation of maritime convergence zones within cold air outbreaks due to the shape of the coastline or sea ice edge |
title_fullStr |
Formation of maritime convergence zones within cold air outbreaks due to the shape of the coastline or sea ice edge |
title_full_unstemmed |
Formation of maritime convergence zones within cold air outbreaks due to the shape of the coastline or sea ice edge |
title_sort |
formation of maritime convergence zones within cold air outbreaks due to the shape of the coastline or sea ice edge |
publisher |
Wiley |
publishDate |
2022 |
url |
https://hdl.handle.net/11250/3062099 https://doi.org/10.1002/qj.4324 |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
Quarterly Journal of the Royal Meteorological Society 2546-2562 148 746 |
op_relation |
urn:issn:0035-9009 https://hdl.handle.net/11250/3062099 https://doi.org/10.1002/qj.4324 cristin:2055388 Quarterly Journal of the Royal Meteorological Society. 2022, 148 (746), 2546-2562. |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no Copyright 2022 The Author(s) |
op_doi |
https://doi.org/10.1002/qj.4324 |
container_title |
Quarterly Journal of the Royal Meteorological Society |
container_volume |
148 |
container_issue |
746 |
container_start_page |
2546 |
op_container_end_page |
2562 |
_version_ |
1766191655121059840 |