Atmospheric Chemistry and Physics The North Atlantic variability structure, storm tracks, and
Abstract. Motivated by the strong evidence that the state of the northern hemisphere vortex in boreal winter influences tropospheric variability, teleconnection patterns over the North Atlantic are defined separately for winter episodes where the zonal wind at 50 hPa and 65 ◦ N is above or below the...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.405.917 2023-05-15T15:13:37+02:00 Atmospheric Chemistry and Physics The North Atlantic variability structure, storm tracks, and Atmos Chem Phys K. Walter H. -f. Graf The Pennsylvania State University CiteSeerX Archives 2004 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.405.917 http://hal.archives-ouvertes.fr/docs/00/29/55/95/PDF/acp-5-239-2005.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.405.917 http://hal.archives-ouvertes.fr/docs/00/29/55/95/PDF/acp-5-239-2005.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://hal.archives-ouvertes.fr/docs/00/29/55/95/PDF/acp-5-239-2005.pdf text 2004 ftciteseerx 2016-01-08T03:03:05Z Abstract. Motivated by the strong evidence that the state of the northern hemisphere vortex in boreal winter influences tropospheric variability, teleconnection patterns over the North Atlantic are defined separately for winter episodes where the zonal wind at 50 hPa and 65 ◦ N is above or below the critical velocity for vertical propagation of zonal planetary wave 1. We argue that the teleconnection structure in the middle and upper troposphere differs considerably between the two regimes of the polar vortex, while this is not the case at sea level. If the polar vortex is strong, there exists one meridional dipole structure of geopotential height in the upper and middle troposphere, which is situated in the central North Atlantic. If the polar vortex is weak, there exist two such dipoles, one over the western and one over the eastern North Atlantic. Storm tracks (and precipitation related with these) are determined by mid and upper tropospheric conditions and we find significant differences of these parameters between the stratospheric regimes. For the strong polar vortex regime, in case of a negative upper tropospheric “NAO” index we find a blocking height situation over the Northeast Atlantic and the strongest storm track of all. It is reaching far north into the Arctic Ocean and has a secondary maximum over the Denmark Strait. Such storm track is not found in composites based on a classic NAO defined by surface pressure differences between the Icelandic Low and the Azores High. Our results suggest that it is important to include the state of the polar vortex strength in any study of the variability over the North Atlantic. Text Arctic Arctic Ocean Denmark Strait North Atlantic Northeast Atlantic Unknown Arctic Arctic Ocean |
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Abstract. Motivated by the strong evidence that the state of the northern hemisphere vortex in boreal winter influences tropospheric variability, teleconnection patterns over the North Atlantic are defined separately for winter episodes where the zonal wind at 50 hPa and 65 ◦ N is above or below the critical velocity for vertical propagation of zonal planetary wave 1. We argue that the teleconnection structure in the middle and upper troposphere differs considerably between the two regimes of the polar vortex, while this is not the case at sea level. If the polar vortex is strong, there exists one meridional dipole structure of geopotential height in the upper and middle troposphere, which is situated in the central North Atlantic. If the polar vortex is weak, there exist two such dipoles, one over the western and one over the eastern North Atlantic. Storm tracks (and precipitation related with these) are determined by mid and upper tropospheric conditions and we find significant differences of these parameters between the stratospheric regimes. For the strong polar vortex regime, in case of a negative upper tropospheric “NAO” index we find a blocking height situation over the Northeast Atlantic and the strongest storm track of all. It is reaching far north into the Arctic Ocean and has a secondary maximum over the Denmark Strait. Such storm track is not found in composites based on a classic NAO defined by surface pressure differences between the Icelandic Low and the Azores High. Our results suggest that it is important to include the state of the polar vortex strength in any study of the variability over the North Atlantic. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Atmos Chem Phys K. Walter H. -f. Graf |
spellingShingle |
Atmos Chem Phys K. Walter H. -f. Graf Atmospheric Chemistry and Physics The North Atlantic variability structure, storm tracks, and |
author_facet |
Atmos Chem Phys K. Walter H. -f. Graf |
author_sort |
Atmos Chem Phys |
title |
Atmospheric Chemistry and Physics The North Atlantic variability structure, storm tracks, and |
title_short |
Atmospheric Chemistry and Physics The North Atlantic variability structure, storm tracks, and |
title_full |
Atmospheric Chemistry and Physics The North Atlantic variability structure, storm tracks, and |
title_fullStr |
Atmospheric Chemistry and Physics The North Atlantic variability structure, storm tracks, and |
title_full_unstemmed |
Atmospheric Chemistry and Physics The North Atlantic variability structure, storm tracks, and |
title_sort |
atmospheric chemistry and physics the north atlantic variability structure, storm tracks, and |
publishDate |
2004 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.405.917 http://hal.archives-ouvertes.fr/docs/00/29/55/95/PDF/acp-5-239-2005.pdf |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Denmark Strait North Atlantic Northeast Atlantic |
genre_facet |
Arctic Arctic Ocean Denmark Strait North Atlantic Northeast Atlantic |
op_source |
http://hal.archives-ouvertes.fr/docs/00/29/55/95/PDF/acp-5-239-2005.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.405.917 http://hal.archives-ouvertes.fr/docs/00/29/55/95/PDF/acp-5-239-2005.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766344146595872768 |