2004: Dynamical prototype of the Arctic Oscillation as revealed by a neutral singular vector
Origin of the Arctic Oscillation (AO) was explored from a dynamical perspective, using a primitive equation model linearized about the observed winter climatology. In order to obtain a leading low-frequency mode of the model atmosphere, singular vector analysis is performed on the linear dynamical o...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.367.3684 2023-05-15T14:22:02+02:00 2004: Dynamical prototype of the Arctic Oscillation as revealed by a neutral singular vector Masahiro Watanabe Fei-fei Jin The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.367.3684 http://www.soest.hawaii.edu/met/Faculty/jff/2004_05 Dynamical Prototype of the Arctic Oscillation as Revealed by a Neutral Singular Vector.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.367.3684 http://www.soest.hawaii.edu/met/Faculty/jff/2004_05 Dynamical Prototype of the Arctic Oscillation as Revealed by a Neutral Singular Vector.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www.soest.hawaii.edu/met/Faculty/jff/2004_05 Dynamical Prototype of the Arctic Oscillation as Revealed by a Neutral Singular Vector.pdf text ftciteseerx 2016-01-08T01:06:30Z Origin of the Arctic Oscillation (AO) was explored from a dynamical perspective, using a primitive equation model linearized about the observed winter climatology. In order to obtain a leading low-frequency mode of the model atmosphere, singular vector analysis is performed on the linear dynamical operator. The singular mode (v vector) with the smallest singular value, referred to as the neutral mode, has a considerable similarity to the observed AO in many aspects, suggesting that, at least in a linear dynamical framework, the AO is a dynamically consistent mode of variability that arises from the zonal asymmetry of the time-mean state. Diagnosis of the neutral mode shows that a zonal flow–stationary wave interaction and an interaction between anomalous and climatological stationary waves are both of importance for maintenance of the spatial structure. Besides, vortex stretching–shrinking is significant in the upper levels, which indicates that a baroclinic process has a certain role as well. It is found that the formation of a hemispheric scale of the neutral mode is accomplished within several days via propagation of Rossby wave packets along jet streams that act as a waveguide. The neutral mode structure is robust for a wide range of model damping parameters, and especially preferred when the damping is weakened in the free troposphere. The corresponding optimal forcing (u vector) indicates that, though its robustness is relatively ambiguous, the neutral mode is most effectively excited by a certain pattern of the extratropical thermal forcing, in addition to a modest sensitivity to the deep heating anomaly over the tropical Indian Ocean. 1. Text Arctic Arctic Unknown Arctic Indian |
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English |
description |
Origin of the Arctic Oscillation (AO) was explored from a dynamical perspective, using a primitive equation model linearized about the observed winter climatology. In order to obtain a leading low-frequency mode of the model atmosphere, singular vector analysis is performed on the linear dynamical operator. The singular mode (v vector) with the smallest singular value, referred to as the neutral mode, has a considerable similarity to the observed AO in many aspects, suggesting that, at least in a linear dynamical framework, the AO is a dynamically consistent mode of variability that arises from the zonal asymmetry of the time-mean state. Diagnosis of the neutral mode shows that a zonal flow–stationary wave interaction and an interaction between anomalous and climatological stationary waves are both of importance for maintenance of the spatial structure. Besides, vortex stretching–shrinking is significant in the upper levels, which indicates that a baroclinic process has a certain role as well. It is found that the formation of a hemispheric scale of the neutral mode is accomplished within several days via propagation of Rossby wave packets along jet streams that act as a waveguide. The neutral mode structure is robust for a wide range of model damping parameters, and especially preferred when the damping is weakened in the free troposphere. The corresponding optimal forcing (u vector) indicates that, though its robustness is relatively ambiguous, the neutral mode is most effectively excited by a certain pattern of the extratropical thermal forcing, in addition to a modest sensitivity to the deep heating anomaly over the tropical Indian Ocean. 1. |
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The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Masahiro Watanabe Fei-fei Jin |
spellingShingle |
Masahiro Watanabe Fei-fei Jin 2004: Dynamical prototype of the Arctic Oscillation as revealed by a neutral singular vector |
author_facet |
Masahiro Watanabe Fei-fei Jin |
author_sort |
Masahiro Watanabe |
title |
2004: Dynamical prototype of the Arctic Oscillation as revealed by a neutral singular vector |
title_short |
2004: Dynamical prototype of the Arctic Oscillation as revealed by a neutral singular vector |
title_full |
2004: Dynamical prototype of the Arctic Oscillation as revealed by a neutral singular vector |
title_fullStr |
2004: Dynamical prototype of the Arctic Oscillation as revealed by a neutral singular vector |
title_full_unstemmed |
2004: Dynamical prototype of the Arctic Oscillation as revealed by a neutral singular vector |
title_sort |
2004: dynamical prototype of the arctic oscillation as revealed by a neutral singular vector |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.367.3684 http://www.soest.hawaii.edu/met/Faculty/jff/2004_05 Dynamical Prototype of the Arctic Oscillation as Revealed by a Neutral Singular Vector.pdf |
geographic |
Arctic Indian |
geographic_facet |
Arctic Indian |
genre |
Arctic Arctic |
genre_facet |
Arctic Arctic |
op_source |
http://www.soest.hawaii.edu/met/Faculty/jff/2004_05 Dynamical Prototype of the Arctic Oscillation as Revealed by a Neutral Singular Vector.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.367.3684 http://www.soest.hawaii.edu/met/Faculty/jff/2004_05 Dynamical Prototype of the Arctic Oscillation as Revealed by a Neutral Singular Vector.pdf |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766294717617668096 |