The positive North Atlantic oscillation with downstream blocking and Middle East snowstorms: The large-scale environment
In this study, the atmospheric conditions for the December 2013 Middle East snowstorm are examined from a case study perspective and by performing a composite analysis of extreme winter events from 1950 to 2013 using reanalysis data. It is revealed that this snowstorm arises from the occurrence of a...
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ftncar:oai:drupal-site.org:articles_16853 2023-09-05T13:21:23+02:00 The positive North Atlantic oscillation with downstream blocking and Middle East snowstorms: The large-scale environment Luo, Dehai (author) Yao, Yao (author) Dai, Aiguo (author) Feldstein, Steven (author) 2015-08-15 application/pdf http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-021-971 https://doi.org/10.1175/JCLI-D-15-0184.1 en eng American Meteorological Society Journal of Climate http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-021-971 doi:10.1175/JCLI-D-15-0184.1 ark:/85065/d70k29rb Copyright 2015 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work. Text article 2015 ftncar https://doi.org/10.1175/JCLI-D-15-0184.1 2023-08-14T18:42:57Z In this study, the atmospheric conditions for the December 2013 Middle East snowstorm are examined from a case study perspective and by performing a composite analysis of extreme winter events from 1950 to 2013 using reanalysis data. It is revealed that this snowstorm arises from the occurrence of an omega (Ω)-type European blocking (EB) with a strong downstream trough that is associated with a southward-displaced positive-phase North Atlantic Oscillation (NAO⁺) event. In the anomaly field, the EB exhibits a northeast–southwest (NE-SW)-tilted dipole structure. The Ω-type EB transports cold air into the Middle East and produces snowfall within the trough over the Middle East. The composite analysis shows that the location of cold temperatures depends strongly on the tilting direction and strength of the EB dipole anomaly. The NE-SW [northwest-southeast (NW-SE)]-tilted EB dipole occurs with a southward (northward)-displaced NAO⁺ event. The NE-SW-tilted EB dipole anomaly is associated with an arching-type low-frequency wave train that spans the North Atlantic, Europe, and the Middle East. This tilting has the most favorable structure for cold air outbreaks over the Middle East and southeastern Europe because this tilting leads to an intense downstream trough over this region. In contrast, a NW-SE-tilted EB dipole anomaly leads to cold temperatures over northwestern Africa and southwestern Europe. The analyses herein also suggest that a strong jet over the North Atlantic may be a precursor for a southward-displaced NAO⁺ event that is usually associated with an Ω-type EB with a NE-SW-tilted dipole in the anomaly height field that favors a cold air outbreak over the Middle East. Article in Journal/Newspaper North Atlantic North Atlantic oscillation OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) Tilting ENVELOPE(-54.065,-54.065,49.700,49.700) Journal of Climate 28 16 6398 6418 |
institution |
Open Polar |
collection |
OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) |
op_collection_id |
ftncar |
language |
English |
description |
In this study, the atmospheric conditions for the December 2013 Middle East snowstorm are examined from a case study perspective and by performing a composite analysis of extreme winter events from 1950 to 2013 using reanalysis data. It is revealed that this snowstorm arises from the occurrence of an omega (Ω)-type European blocking (EB) with a strong downstream trough that is associated with a southward-displaced positive-phase North Atlantic Oscillation (NAO⁺) event. In the anomaly field, the EB exhibits a northeast–southwest (NE-SW)-tilted dipole structure. The Ω-type EB transports cold air into the Middle East and produces snowfall within the trough over the Middle East. The composite analysis shows that the location of cold temperatures depends strongly on the tilting direction and strength of the EB dipole anomaly. The NE-SW [northwest-southeast (NW-SE)]-tilted EB dipole occurs with a southward (northward)-displaced NAO⁺ event. The NE-SW-tilted EB dipole anomaly is associated with an arching-type low-frequency wave train that spans the North Atlantic, Europe, and the Middle East. This tilting has the most favorable structure for cold air outbreaks over the Middle East and southeastern Europe because this tilting leads to an intense downstream trough over this region. In contrast, a NW-SE-tilted EB dipole anomaly leads to cold temperatures over northwestern Africa and southwestern Europe. The analyses herein also suggest that a strong jet over the North Atlantic may be a precursor for a southward-displaced NAO⁺ event that is usually associated with an Ω-type EB with a NE-SW-tilted dipole in the anomaly height field that favors a cold air outbreak over the Middle East. |
author2 |
Luo, Dehai (author) Yao, Yao (author) Dai, Aiguo (author) Feldstein, Steven (author) |
format |
Article in Journal/Newspaper |
title |
The positive North Atlantic oscillation with downstream blocking and Middle East snowstorms: The large-scale environment |
spellingShingle |
The positive North Atlantic oscillation with downstream blocking and Middle East snowstorms: The large-scale environment |
title_short |
The positive North Atlantic oscillation with downstream blocking and Middle East snowstorms: The large-scale environment |
title_full |
The positive North Atlantic oscillation with downstream blocking and Middle East snowstorms: The large-scale environment |
title_fullStr |
The positive North Atlantic oscillation with downstream blocking and Middle East snowstorms: The large-scale environment |
title_full_unstemmed |
The positive North Atlantic oscillation with downstream blocking and Middle East snowstorms: The large-scale environment |
title_sort |
positive north atlantic oscillation with downstream blocking and middle east snowstorms: the large-scale environment |
publisher |
American Meteorological Society |
publishDate |
2015 |
url |
http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-021-971 https://doi.org/10.1175/JCLI-D-15-0184.1 |
long_lat |
ENVELOPE(-54.065,-54.065,49.700,49.700) |
geographic |
Tilting |
geographic_facet |
Tilting |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
Journal of Climate http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-021-971 doi:10.1175/JCLI-D-15-0184.1 ark:/85065/d70k29rb |
op_rights |
Copyright 2015 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work. |
op_doi |
https://doi.org/10.1175/JCLI-D-15-0184.1 |
container_title |
Journal of Climate |
container_volume |
28 |
container_issue |
16 |
container_start_page |
6398 |
op_container_end_page |
6418 |
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1776201989210767360 |