Stratosphere–Troposphere Coupling in a Relatively Simple AGCM: The Importance of Stratospheric Variability
The impact of stratospheric variability on the dynamical coupling between the stratosphere and the troposphere is explored in a relatively simple atmospheric general circulation model. Variability of the model’s stratospheric polar vortex, or polar night jet, is induced by topographically forced sta...
Main Authors: | , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2009
|
Subjects: | |
Online Access: | https://doi.org/10.7916/D8D79NK2 |
id |
ftcolumbiauniv:oai:academiccommons.columbia.edu:10.7916/D8D79NK2 |
---|---|
record_format |
openpolar |
spelling |
ftcolumbiauniv:oai:academiccommons.columbia.edu:10.7916/D8D79NK2 2023-05-15T18:02:16+02:00 Stratosphere–Troposphere Coupling in a Relatively Simple AGCM: The Importance of Stratospheric Variability Gerber, Edwin P. Polvani, Lorenzo M. 2009 https://doi.org/10.7916/D8D79NK2 English eng https://doi.org/10.7916/D8D79NK2 Atmosphere Meteorology Upper Articles 2009 ftcolumbiauniv https://doi.org/10.7916/D8D79NK2 2019-04-04T08:10:15Z The impact of stratospheric variability on the dynamical coupling between the stratosphere and the troposphere is explored in a relatively simple atmospheric general circulation model. Variability of the model’s stratospheric polar vortex, or polar night jet, is induced by topographically forced stationary waves. A robust relationship is found between the strength of the stratospheric polar vortex and the latitude of the tropospheric jet, confirming and extending earlier results in the absence of stationary waves. In both the climatological mean and on intraseasonal time scales, a weaker vortex is associated with an equatorward shift in the tropospheric jet and vice versa. It is found that the mean structure and variability of the vortex in the model is very sensitive to the amplitude of the topography and that Northern Hemisphere–like variability, with a realistic frequency of stratospheric sudden warming events, occurs only for a relatively narrow range of topographic heights. When the model captures sudden warming events with fidelity, however, the exchange of information both upward and downward between the troposphere and stratosphere closely resembles that in observations. The influence of stratospheric variability on variability in the troposphere is demonstrated by comparing integrations with and without an active stratosphere. A realistic, time-dependent stratospheric circulation increases the persistence of the tropospheric annular modes, and the dynamical coupling is most apparent prior to and following stratospheric sudden warming events. Article in Journal/Newspaper polar night Columbia University: Academic Commons |
institution |
Open Polar |
collection |
Columbia University: Academic Commons |
op_collection_id |
ftcolumbiauniv |
language |
English |
topic |
Atmosphere Meteorology Upper |
spellingShingle |
Atmosphere Meteorology Upper Gerber, Edwin P. Polvani, Lorenzo M. Stratosphere–Troposphere Coupling in a Relatively Simple AGCM: The Importance of Stratospheric Variability |
topic_facet |
Atmosphere Meteorology Upper |
description |
The impact of stratospheric variability on the dynamical coupling between the stratosphere and the troposphere is explored in a relatively simple atmospheric general circulation model. Variability of the model’s stratospheric polar vortex, or polar night jet, is induced by topographically forced stationary waves. A robust relationship is found between the strength of the stratospheric polar vortex and the latitude of the tropospheric jet, confirming and extending earlier results in the absence of stationary waves. In both the climatological mean and on intraseasonal time scales, a weaker vortex is associated with an equatorward shift in the tropospheric jet and vice versa. It is found that the mean structure and variability of the vortex in the model is very sensitive to the amplitude of the topography and that Northern Hemisphere–like variability, with a realistic frequency of stratospheric sudden warming events, occurs only for a relatively narrow range of topographic heights. When the model captures sudden warming events with fidelity, however, the exchange of information both upward and downward between the troposphere and stratosphere closely resembles that in observations. The influence of stratospheric variability on variability in the troposphere is demonstrated by comparing integrations with and without an active stratosphere. A realistic, time-dependent stratospheric circulation increases the persistence of the tropospheric annular modes, and the dynamical coupling is most apparent prior to and following stratospheric sudden warming events. |
format |
Article in Journal/Newspaper |
author |
Gerber, Edwin P. Polvani, Lorenzo M. |
author_facet |
Gerber, Edwin P. Polvani, Lorenzo M. |
author_sort |
Gerber, Edwin P. |
title |
Stratosphere–Troposphere Coupling in a Relatively Simple AGCM: The Importance of Stratospheric Variability |
title_short |
Stratosphere–Troposphere Coupling in a Relatively Simple AGCM: The Importance of Stratospheric Variability |
title_full |
Stratosphere–Troposphere Coupling in a Relatively Simple AGCM: The Importance of Stratospheric Variability |
title_fullStr |
Stratosphere–Troposphere Coupling in a Relatively Simple AGCM: The Importance of Stratospheric Variability |
title_full_unstemmed |
Stratosphere–Troposphere Coupling in a Relatively Simple AGCM: The Importance of Stratospheric Variability |
title_sort |
stratosphere–troposphere coupling in a relatively simple agcm: the importance of stratospheric variability |
publishDate |
2009 |
url |
https://doi.org/10.7916/D8D79NK2 |
genre |
polar night |
genre_facet |
polar night |
op_relation |
https://doi.org/10.7916/D8D79NK2 |
op_doi |
https://doi.org/10.7916/D8D79NK2 |
_version_ |
1766172066200944640 |