A global climatology of favourable conditions for polar lows
Abstract Polar lows (PLs) are small‐scale and intense low‐pressure systems that form at high latitudes in both hemispheres. Due to their limited spatial scale and brief lifetimes, weather and climate models are often unable to resolve these systems. One way to overcome this problem is to define a su...
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crwiley:10.1002/qj.888 2024-06-23T07:54:26+00:00 A global climatology of favourable conditions for polar lows Kolstad, Erik W. Norwegian Research Council 2011 http://dx.doi.org/10.1002/qj.888 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fqj.888 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.888 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Quarterly Journal of the Royal Meteorological Society volume 137, issue 660, page 1749-1761 ISSN 0035-9009 1477-870X journal-article 2011 crwiley https://doi.org/10.1002/qj.888 2024-06-06T04:20:49Z Abstract Polar lows (PLs) are small‐scale and intense low‐pressure systems that form at high latitudes in both hemispheres. Due to their limited spatial scale and brief lifetimes, weather and climate models are often unable to resolve these systems. One way to overcome this problem is to define a suitable proxy for PLs, with which the likelihood of PL formation can be assessed even in coarse‐resolution datasets. This study draws on previous studies and an empirical database of 63 PLs to quantify the respective influences of low‐level static stability and upper‐level forcing on PL formation, as both of these factors are known to favour PL development. Little redundancy between the two parameters is found. After defining threshold values for the two parameters, climatological properties of favourable conditions for PLs are computed for the North Atlantic, the North‐West Pacific and the Southern Hemisphere. The low‐level static stability, which is strongly modified during marine cold‐air outbreaks, puts important constraints on where PLs can form, while the upper‐level forcing determines whether or not they will form. As a result of the climatologically lower tropopause in the Labrador Sea region, favourable conditions for PLs occur more often there than in the Nordic Seas, which has long been believed to be the main PL region in the Northern Hemisphere (NH). In the Southern Hemisphere, favourable conditions for PLs occur substantially less often than in the NH. The PL index defined here is suitable for other climatological studies and PL forecasting. Copyright © 2011 Royal Meteorological Society Article in Journal/Newspaper Labrador Sea Nordic Seas North Atlantic Wiley Online Library Pacific Quarterly Journal of the Royal Meteorological Society 137 660 1749 1761 |
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Wiley Online Library |
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English |
description |
Abstract Polar lows (PLs) are small‐scale and intense low‐pressure systems that form at high latitudes in both hemispheres. Due to their limited spatial scale and brief lifetimes, weather and climate models are often unable to resolve these systems. One way to overcome this problem is to define a suitable proxy for PLs, with which the likelihood of PL formation can be assessed even in coarse‐resolution datasets. This study draws on previous studies and an empirical database of 63 PLs to quantify the respective influences of low‐level static stability and upper‐level forcing on PL formation, as both of these factors are known to favour PL development. Little redundancy between the two parameters is found. After defining threshold values for the two parameters, climatological properties of favourable conditions for PLs are computed for the North Atlantic, the North‐West Pacific and the Southern Hemisphere. The low‐level static stability, which is strongly modified during marine cold‐air outbreaks, puts important constraints on where PLs can form, while the upper‐level forcing determines whether or not they will form. As a result of the climatologically lower tropopause in the Labrador Sea region, favourable conditions for PLs occur more often there than in the Nordic Seas, which has long been believed to be the main PL region in the Northern Hemisphere (NH). In the Southern Hemisphere, favourable conditions for PLs occur substantially less often than in the NH. The PL index defined here is suitable for other climatological studies and PL forecasting. Copyright © 2011 Royal Meteorological Society |
author2 |
Norwegian Research Council |
format |
Article in Journal/Newspaper |
author |
Kolstad, Erik W. |
spellingShingle |
Kolstad, Erik W. A global climatology of favourable conditions for polar lows |
author_facet |
Kolstad, Erik W. |
author_sort |
Kolstad, Erik W. |
title |
A global climatology of favourable conditions for polar lows |
title_short |
A global climatology of favourable conditions for polar lows |
title_full |
A global climatology of favourable conditions for polar lows |
title_fullStr |
A global climatology of favourable conditions for polar lows |
title_full_unstemmed |
A global climatology of favourable conditions for polar lows |
title_sort |
global climatology of favourable conditions for polar lows |
publisher |
Wiley |
publishDate |
2011 |
url |
http://dx.doi.org/10.1002/qj.888 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fqj.888 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.888 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Labrador Sea Nordic Seas North Atlantic |
genre_facet |
Labrador Sea Nordic Seas North Atlantic |
op_source |
Quarterly Journal of the Royal Meteorological Society volume 137, issue 660, page 1749-1761 ISSN 0035-9009 1477-870X |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/qj.888 |
container_title |
Quarterly Journal of the Royal Meteorological Society |
container_volume |
137 |
container_issue |
660 |
container_start_page |
1749 |
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1761 |
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1802646589931520000 |