The role of the stratosphere in Iberian Peninsula rainfall: a preliminary approach in February
This paper attempts to establish a connection between stratospheric anomalies in the North Pole and rainfall on the Iberian Peninsula through the occurrence of major midwinter warmings (MMWs) and cold events (CEs), taking February as a preliminary approach. We define the MMWs as the warmings which b...
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ftubarcepubl:oai:diposit.ub.edu:2445/122769 2024-02-11T10:01:40+01:00 The role of the stratosphere in Iberian Peninsula rainfall: a preliminary approach in February López Bustins, Joan Albert Esteban Vea, Pere Labitzke, K Langematz, Ulrike 2007-06-09 14 p. application/pdf http://hdl.handle.net/2445/122769 eng eng Elsevier Ltd Versió postprint del document publicat a: https://doi.org/10.1016/j.jastp.2007.05.015 Journal of Atmospheric and Solar-Terrestrial Physics, 2007, vol. 69, num. 12, p. 1471-1484 Articles publicats en revistes (Geografia) https://doi.org/10.1016/j.jastp.2007.05.015 1364-6826 http://hdl.handle.net/2445/122769 579191 (c) Elsevier Ltd, 2007 info:eu-repo/semantics/openAccess Climatologia Meteorologia sinòptica Precipitacions (Meteorologia) Circulació atmosfèrica Península Ibèrica Climatology Synoptic meteorology Precipitations (Meteorology) Atmospheric circulation Iberian Peninsula info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion 2007 ftubarcepubl https://doi.org/10.1016/j.jastp.2007.05.015 2024-01-24T01:04:06Z This paper attempts to establish a connection between stratospheric anomalies in the North Pole and rainfall on the Iberian Peninsula through the occurrence of major midwinter warmings (MMWs) and cold events (CEs), taking February as a preliminary approach. We define the MMWs as the warmings which break down the polar vortex, whereas the CEs are the episodes in which the polar vortex remains cold and undisturbed. Both anomalies lead to a wind anomaly around the north polar stratosphere, which is connected with a shortly lagged tropospheric anomaly through a stratosphere-troposphere coupling in winter. A T-mode principal component analysis (PCA) was used as an objective pattern classification method for identifying the main daily surface-level pressure (SLP) patterns for February for the 1961-1990 reference period. Subsequently, those February months with an MMW or a CE influence in the troposphere are identified in the whole study period (1958-2000) by means of the Arctic Oscillation Index (AOI). Thus, performing the same analysis for the selected February months, new principal patterns for detecting changes in surface circulation structure and morphology are obtained. The results show a significant decrease in the westerlies and a southward shift of the storm tracks in Western Europe some weeks after an MMW occurrence, leading to an increase in precipitation in western Iberia and a slight decrease on the eastern Mediterranean fringe. The results are quite the opposite under a CE influence: the westerlies are strengthened and shifted northwards due to the displacement of the Atlantic anticyclone towards Central Europe; dry conditions are established throughout Iberia, except for the Mediterranean fringe, where precipitation shows a considerable increase due to the greater frequency of the northeasterly winds. Finally, an 11-year sunspot cycle-quasibiennial oscillation (QBO) modulation might be demonstrated in Iberian rainfall in February through the occurrence of these stratospheric anomalies. Article in Journal/Newspaper Arctic North Pole Dipòsit Digital de la Universitat de Barcelona Arctic North Pole Midwinter ENVELOPE(139.931,139.931,-66.690,-66.690) Journal of Atmospheric and Solar-Terrestrial Physics 69 12 1471 1484 |
institution |
Open Polar |
collection |
Dipòsit Digital de la Universitat de Barcelona |
op_collection_id |
ftubarcepubl |
language |
English |
topic |
Climatologia Meteorologia sinòptica Precipitacions (Meteorologia) Circulació atmosfèrica Península Ibèrica Climatology Synoptic meteorology Precipitations (Meteorology) Atmospheric circulation Iberian Peninsula |
spellingShingle |
Climatologia Meteorologia sinòptica Precipitacions (Meteorologia) Circulació atmosfèrica Península Ibèrica Climatology Synoptic meteorology Precipitations (Meteorology) Atmospheric circulation Iberian Peninsula López Bustins, Joan Albert Esteban Vea, Pere Labitzke, K Langematz, Ulrike The role of the stratosphere in Iberian Peninsula rainfall: a preliminary approach in February |
topic_facet |
Climatologia Meteorologia sinòptica Precipitacions (Meteorologia) Circulació atmosfèrica Península Ibèrica Climatology Synoptic meteorology Precipitations (Meteorology) Atmospheric circulation Iberian Peninsula |
description |
This paper attempts to establish a connection between stratospheric anomalies in the North Pole and rainfall on the Iberian Peninsula through the occurrence of major midwinter warmings (MMWs) and cold events (CEs), taking February as a preliminary approach. We define the MMWs as the warmings which break down the polar vortex, whereas the CEs are the episodes in which the polar vortex remains cold and undisturbed. Both anomalies lead to a wind anomaly around the north polar stratosphere, which is connected with a shortly lagged tropospheric anomaly through a stratosphere-troposphere coupling in winter. A T-mode principal component analysis (PCA) was used as an objective pattern classification method for identifying the main daily surface-level pressure (SLP) patterns for February for the 1961-1990 reference period. Subsequently, those February months with an MMW or a CE influence in the troposphere are identified in the whole study period (1958-2000) by means of the Arctic Oscillation Index (AOI). Thus, performing the same analysis for the selected February months, new principal patterns for detecting changes in surface circulation structure and morphology are obtained. The results show a significant decrease in the westerlies and a southward shift of the storm tracks in Western Europe some weeks after an MMW occurrence, leading to an increase in precipitation in western Iberia and a slight decrease on the eastern Mediterranean fringe. The results are quite the opposite under a CE influence: the westerlies are strengthened and shifted northwards due to the displacement of the Atlantic anticyclone towards Central Europe; dry conditions are established throughout Iberia, except for the Mediterranean fringe, where precipitation shows a considerable increase due to the greater frequency of the northeasterly winds. Finally, an 11-year sunspot cycle-quasibiennial oscillation (QBO) modulation might be demonstrated in Iberian rainfall in February through the occurrence of these stratospheric anomalies. |
format |
Article in Journal/Newspaper |
author |
López Bustins, Joan Albert Esteban Vea, Pere Labitzke, K Langematz, Ulrike |
author_facet |
López Bustins, Joan Albert Esteban Vea, Pere Labitzke, K Langematz, Ulrike |
author_sort |
López Bustins, Joan Albert |
title |
The role of the stratosphere in Iberian Peninsula rainfall: a preliminary approach in February |
title_short |
The role of the stratosphere in Iberian Peninsula rainfall: a preliminary approach in February |
title_full |
The role of the stratosphere in Iberian Peninsula rainfall: a preliminary approach in February |
title_fullStr |
The role of the stratosphere in Iberian Peninsula rainfall: a preliminary approach in February |
title_full_unstemmed |
The role of the stratosphere in Iberian Peninsula rainfall: a preliminary approach in February |
title_sort |
role of the stratosphere in iberian peninsula rainfall: a preliminary approach in february |
publisher |
Elsevier Ltd |
publishDate |
2007 |
url |
http://hdl.handle.net/2445/122769 |
long_lat |
ENVELOPE(139.931,139.931,-66.690,-66.690) |
geographic |
Arctic North Pole Midwinter |
geographic_facet |
Arctic North Pole Midwinter |
genre |
Arctic North Pole |
genre_facet |
Arctic North Pole |
op_relation |
Versió postprint del document publicat a: https://doi.org/10.1016/j.jastp.2007.05.015 Journal of Atmospheric and Solar-Terrestrial Physics, 2007, vol. 69, num. 12, p. 1471-1484 Articles publicats en revistes (Geografia) https://doi.org/10.1016/j.jastp.2007.05.015 1364-6826 http://hdl.handle.net/2445/122769 579191 |
op_rights |
(c) Elsevier Ltd, 2007 info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1016/j.jastp.2007.05.015 |
container_title |
Journal of Atmospheric and Solar-Terrestrial Physics |
container_volume |
69 |
container_issue |
12 |
container_start_page |
1471 |
op_container_end_page |
1484 |
_version_ |
1790597465598066688 |