Quantifying the Eddy Feedback and the Persistence of the Zonal Index in an Idealized Atmospheric Model
An idealized atmospheric model is employed to quantify the strength of the eddy feedback and the persistence of the zonal index. The strength of the surface frictional damping on the zonal index is varied, and an external zonal momentum forcing is included to compensate for the momentum change assoc...
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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American Meteorological Society
2010
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| Online Access: | http://hdl.handle.net/1721.1/57469 https://orcid.org/0000-0002-6716-1576 |
| _version_ | 1811083210692493312 |
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| author | Chen, Gang R. Plumb, R. Alan |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Chen, Gang R. Plumb, R. Alan |
| author_sort | Chen, Gang R. |
| collection | MIT |
| description | An idealized atmospheric model is employed to quantify the strength of the eddy feedback and the persistence of the zonal index. The strength of the surface frictional damping on the zonal index is varied, and an external zonal momentum forcing is included to compensate for the momentum change associated with the friction change such that the climatological jet latitude and shape are unchanged.
The model can generate a nearly identical climatology and leading mode of the zonal mean zonal wind for different frictional damping rates, except when the jet undergoes a regime transition. For those experiments without a regime transition, as the surface friction is increased, the strength of eddy feedback is enhanced but the zonal index becomes less persistent. A simple feedback model suggests that the e-folding decorrelation time scale of the zonal index can be determined by the frictional damping rate and the strength of eddy feedback. The strength of eddy feedback is found to be related to the instantaneous vertical wind shears near the surface controlled by the frictional damping. Furthermore, the climate response to an external zonal torque is proportional to the decorrelation time scale, although the simple prediction used here overestimates the climate response by a factor of 2. |
| first_indexed | 2024-09-23T12:28:32Z |
| format | Article |
| id | mit-1721.1/57469 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T12:28:32Z |
| publishDate | 2010 |
| publisher | American Meteorological Society |
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| spelling | mit-1721.1/574692022-09-28T08:04:50Z Quantifying the Eddy Feedback and the Persistence of the Zonal Index in an Idealized Atmospheric Model Chen, Gang R. Plumb, R. Alan Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Plumb, R. Alan Chen, Gang R. Plumb, R. Alan feedback eddies climate models An idealized atmospheric model is employed to quantify the strength of the eddy feedback and the persistence of the zonal index. The strength of the surface frictional damping on the zonal index is varied, and an external zonal momentum forcing is included to compensate for the momentum change associated with the friction change such that the climatological jet latitude and shape are unchanged. The model can generate a nearly identical climatology and leading mode of the zonal mean zonal wind for different frictional damping rates, except when the jet undergoes a regime transition. For those experiments without a regime transition, as the surface friction is increased, the strength of eddy feedback is enhanced but the zonal index becomes less persistent. A simple feedback model suggests that the e-folding decorrelation time scale of the zonal index can be determined by the frictional damping rate and the strength of eddy feedback. The strength of eddy feedback is found to be related to the instantaneous vertical wind shears near the surface controlled by the frictional damping. Furthermore, the climate response to an external zonal torque is proportional to the decorrelation time scale, although the simple prediction used here overestimates the climate response by a factor of 2. 2010-08-04T13:56:56Z 2010-08-04T13:56:56Z 2009-12 2009-04 Article http://purl.org/eprint/type/JournalArticle 1520-0469 0022-4928 http://hdl.handle.net/1721.1/57469 Chen, Gang, R. Alan Plumb, 2009: Quantifying the Eddy Feedback and the Persistence of the Zonal Index in an Idealized Atmospheric Model. J. Atmos. Sci., 66, 3707-3720 © 2010 American Meteorological Society https://orcid.org/0000-0002-6716-1576 en_US http://dx.doi.org/10.1175/2009jas3165.1 Journal of the Atmospheric Sciences Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Meteorological Society American Meteorological Society |
| spellingShingle | feedback eddies climate models Chen, Gang R. Plumb, R. Alan Quantifying the Eddy Feedback and the Persistence of the Zonal Index in an Idealized Atmospheric Model |
| title | Quantifying the Eddy Feedback and the Persistence of the Zonal Index in an Idealized Atmospheric Model |
| title_full | Quantifying the Eddy Feedback and the Persistence of the Zonal Index in an Idealized Atmospheric Model |
| title_fullStr | Quantifying the Eddy Feedback and the Persistence of the Zonal Index in an Idealized Atmospheric Model |
| title_full_unstemmed | Quantifying the Eddy Feedback and the Persistence of the Zonal Index in an Idealized Atmospheric Model |
| title_short | Quantifying the Eddy Feedback and the Persistence of the Zonal Index in an Idealized Atmospheric Model |
| title_sort | quantifying the eddy feedback and the persistence of the zonal index in an idealized atmospheric model |
| topic | feedback eddies climate models |
| url | http://hdl.handle.net/1721.1/57469 https://orcid.org/0000-0002-6716-1576 |
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