The Downward Influence of Stratospheric Sudden Warmings
The coupling between the stratosphere and the troposphere following two major stratospheric sudden warmings is studied in the Canadian Middle Atmosphere Model using a nudging technique by which the zonal-mean evolution of the reference sudden warmings are artificially induced in an ~100-member ensem...
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ftcolumbiauniv:oai:academiccommons.columbia.edu:10.7916/D8PV6JWD 2023-05-15T17:34:25+02:00 The Downward Influence of Stratospheric Sudden Warmings Hitchcock, Peter Simpson, Isla R. 2014 https://doi.org/10.7916/D8PV6JWD English eng American Meteorological Society https://doi.org/10.7916/D8PV6JWD Meteorology Atmosphere Upper Mathematics Articles 2014 ftcolumbiauniv https://doi.org/10.7916/D8PV6JWD 2019-04-04T08:13:28Z The coupling between the stratosphere and the troposphere following two major stratospheric sudden warmings is studied in the Canadian Middle Atmosphere Model using a nudging technique by which the zonal-mean evolution of the reference sudden warmings are artificially induced in an ~100-member ensemble spun off from a control simulation. Both reference warmings are taken from a freely running integration of the model. One event is a displacement, the other is a split, and both are followed by extended recoveries in the lower stratosphere. The methodology permits a statistically robust study of their influence on the troposphere below. The nudged ensembles exhibit a tropospheric annular mode response closely analogous to that seen in observations, confirming the downward influence of sudden warmings on the troposphere in a comprehensive model. This tropospheric response coincides more closely with the lower-stratospheric annular mode anomalies than with the midstratospheric wind reversal. In addition to the expected synoptic-scale eddy feedback, the planetary-scale eddies also reinforce the tropospheric wind changes, apparently responding directly to the stratospheric anomalies. Furthermore, despite the zonal symmetry of the stratospheric perturbation, a highly zonally asymmetric near-surface response is produced, corresponding to a strongly negative phase of the North Atlantic Oscillation with a much weaker response over the Pacific basin that matches composites of sudden warmings from the Interim ECMWF Re-Analysis (ERA-Interim). Phase 5 of the Coupled Model Intercomparison Project models exhibit a similar response, though in most models the response’s magnitude is underrepresented. Article in Journal/Newspaper North Atlantic North Atlantic oscillation Columbia University: Academic Commons Pacific |
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Open Polar |
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Columbia University: Academic Commons |
op_collection_id |
ftcolumbiauniv |
language |
English |
topic |
Meteorology Atmosphere Upper Mathematics |
spellingShingle |
Meteorology Atmosphere Upper Mathematics Hitchcock, Peter Simpson, Isla R. The Downward Influence of Stratospheric Sudden Warmings |
topic_facet |
Meteorology Atmosphere Upper Mathematics |
description |
The coupling between the stratosphere and the troposphere following two major stratospheric sudden warmings is studied in the Canadian Middle Atmosphere Model using a nudging technique by which the zonal-mean evolution of the reference sudden warmings are artificially induced in an ~100-member ensemble spun off from a control simulation. Both reference warmings are taken from a freely running integration of the model. One event is a displacement, the other is a split, and both are followed by extended recoveries in the lower stratosphere. The methodology permits a statistically robust study of their influence on the troposphere below. The nudged ensembles exhibit a tropospheric annular mode response closely analogous to that seen in observations, confirming the downward influence of sudden warmings on the troposphere in a comprehensive model. This tropospheric response coincides more closely with the lower-stratospheric annular mode anomalies than with the midstratospheric wind reversal. In addition to the expected synoptic-scale eddy feedback, the planetary-scale eddies also reinforce the tropospheric wind changes, apparently responding directly to the stratospheric anomalies. Furthermore, despite the zonal symmetry of the stratospheric perturbation, a highly zonally asymmetric near-surface response is produced, corresponding to a strongly negative phase of the North Atlantic Oscillation with a much weaker response over the Pacific basin that matches composites of sudden warmings from the Interim ECMWF Re-Analysis (ERA-Interim). Phase 5 of the Coupled Model Intercomparison Project models exhibit a similar response, though in most models the response’s magnitude is underrepresented. |
format |
Article in Journal/Newspaper |
author |
Hitchcock, Peter Simpson, Isla R. |
author_facet |
Hitchcock, Peter Simpson, Isla R. |
author_sort |
Hitchcock, Peter |
title |
The Downward Influence of Stratospheric Sudden Warmings |
title_short |
The Downward Influence of Stratospheric Sudden Warmings |
title_full |
The Downward Influence of Stratospheric Sudden Warmings |
title_fullStr |
The Downward Influence of Stratospheric Sudden Warmings |
title_full_unstemmed |
The Downward Influence of Stratospheric Sudden Warmings |
title_sort |
downward influence of stratospheric sudden warmings |
publisher |
American Meteorological Society |
publishDate |
2014 |
url |
https://doi.org/10.7916/D8PV6JWD |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
https://doi.org/10.7916/D8PV6JWD |
op_doi |
https://doi.org/10.7916/D8PV6JWD |
_version_ |
1766133237226143744 |