Annular modes and apparent eddy feedbacks in the Southern Hemisphere
Lagged correlation analysis is often used to infer intraseasonal dynamical effects but is known to be affected by nonstationarity. We highlight a pronounced quasi 2 year peak in the anomalous zonal wind and eddy momentum flux convergence power spectra in the Southern Hemisphere, which is prima facie...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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American Geophysical Union (AGU)
2017
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| Online Access: | http://hdl.handle.net/1721.1/106332 https://orcid.org/0000-0002-6716-1576 |
| _version_ | 1811080020848803840 |
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| author | Byrne, Nicholas J. Shepherd, Theodore G. Woollings, Tim 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 Byrne, Nicholas J. Shepherd, Theodore G. Woollings, Tim Plumb, R. Alan |
| author_sort | Byrne, Nicholas J. |
| collection | MIT |
| description | Lagged correlation analysis is often used to infer intraseasonal dynamical effects but is known to be affected by nonstationarity. We highlight a pronounced quasi 2 year peak in the anomalous zonal wind and eddy momentum flux convergence power spectra in the Southern Hemisphere, which is prima facie evidence for nonstationarity. We then investigate the consequences of this nonstationarity for the Southern Annular Mode and for eddy momentum flux convergence. We argue that positive lagged correlations previously attributed to the existence of an eddy feedback are more plausibly attributed to nonstationary interannual variability external to any potential feedback process in the midlatitude troposphere. The
findings have implications for the diagnosis of feedbacks in both models and reanalysis data as well as for understanding the mechanisms underlying variations in the zonal wind. |
| first_indexed | 2024-09-23T11:24:26Z |
| format | Article |
| id | mit-1721.1/106332 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T11:24:26Z |
| publishDate | 2017 |
| publisher | American Geophysical Union (AGU) |
| record_format | dspace |
| spelling | mit-1721.1/1063322024-05-15T05:24:07Z Annular modes and apparent eddy feedbacks in the Southern Hemisphere Byrne, Nicholas J. Shepherd, Theodore G. Woollings, Tim Plumb, R. Alan Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Plumb, Raymond Alan Lagged correlation analysis is often used to infer intraseasonal dynamical effects but is known to be affected by nonstationarity. We highlight a pronounced quasi 2 year peak in the anomalous zonal wind and eddy momentum flux convergence power spectra in the Southern Hemisphere, which is prima facie evidence for nonstationarity. We then investigate the consequences of this nonstationarity for the Southern Annular Mode and for eddy momentum flux convergence. We argue that positive lagged correlations previously attributed to the existence of an eddy feedback are more plausibly attributed to nonstationary interannual variability external to any potential feedback process in the midlatitude troposphere. The findings have implications for the diagnosis of feedbacks in both models and reanalysis data as well as for understanding the mechanisms underlying variations in the zonal wind. 2017-01-10T19:55:05Z 2017-01-10T19:55:05Z 2016-04 2016-04 Article http://purl.org/eprint/type/JournalArticle 0094-8276 http://hdl.handle.net/1721.1/106332 Byrne, Nicholas J. et al. “Annular Modes and Apparent Eddy Feedbacks in the Southern Hemisphere.” Geophysical Research Letters 43.8 (2016): 3897–3902. https://orcid.org/0000-0002-6716-1576 en_US http://dx.doi.org/10.1002/2016GL068851 Geophysical Research Letters Creative Commons Attribution-NonCommercial-NoDerivs License http://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf American Geophysical Union (AGU) American Geophysical Union |
| spellingShingle | Byrne, Nicholas J. Shepherd, Theodore G. Woollings, Tim Plumb, R. Alan Annular modes and apparent eddy feedbacks in the Southern Hemisphere |
| title | Annular modes and apparent eddy feedbacks in the Southern Hemisphere |
| title_full | Annular modes and apparent eddy feedbacks in the Southern Hemisphere |
| title_fullStr | Annular modes and apparent eddy feedbacks in the Southern Hemisphere |
| title_full_unstemmed | Annular modes and apparent eddy feedbacks in the Southern Hemisphere |
| title_short | Annular modes and apparent eddy feedbacks in the Southern Hemisphere |
| title_sort | annular modes and apparent eddy feedbacks in the southern hemisphere |
| url | http://hdl.handle.net/1721.1/106332 https://orcid.org/0000-0002-6716-1576 |
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