Seasonal Variability of the Polar Stratospheric Vortex in an Idealized AGCM with Varying Tropospheric Wave Forcing
The seasonal variability of the polar stratospheric vortex is studied in a simplified AGCM driven by specified equilibrium temperature distributions. Seasonal variations in equilibrium temperature are imposed in the stratosphere only, enabling the study of stratosphere–troposphere coupling on season...
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| Format: | Article |
| Language: | en_US |
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American Meteorological Society
2016
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| Online Access: | http://hdl.handle.net/1721.1/100780 https://orcid.org/0000-0002-6716-1576 https://orcid.org/0000-0002-9828-9484 |
| _version_ | 1826201051828584448 |
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| author | Sheshadri, Aditi Plumb, R. Alan Gerber, Edwin P. |
| 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 Sheshadri, Aditi Plumb, R. Alan Gerber, Edwin P. |
| author_sort | Sheshadri, Aditi |
| collection | MIT |
| description | The seasonal variability of the polar stratospheric vortex is studied in a simplified AGCM driven by specified equilibrium temperature distributions. Seasonal variations in equilibrium temperature are imposed in the stratosphere only, enabling the study of stratosphere–troposphere coupling on seasonal time scales, without the complication of an internal tropospheric seasonal cycle. The model is forced with different shapes and amplitudes of simple bottom topography, resulting in a range of stratospheric climates. The effect of these different kinds of topography on the seasonal variability of the strength of the polar vortex, the average timing and variability in timing of the final breakup of the vortex (final warming events), the conditions of occurrence and frequency of midwinter warming events, and the impact of the stratospheric seasonal cycle on the troposphere are explored. The inclusion of wavenumber-1 and wavenumber-2 topographies results in very different stratospheric seasonal variability. Hemispheric differences in stratospheric seasonal variability are recovered in the model with appropriate choices of wave-2 topography. In the model experiment with a realistic Northern Hemisphere–like frequency of midwinter warming events, the distribution of the intervals between these events suggests that the model has no year-to-year memory. When forced with wave-1 topography, the gross features of seasonal variability are similar to those forced with wave-2 topography, but the dependence on forcing magnitude is weaker. Further, the frequency of major warming events has a nonmonotonic dependence on forcing magnitude and never reaches the frequency observed in the Northern Hemisphere. |
| first_indexed | 2024-09-23T11:45:53Z |
| format | Article |
| id | mit-1721.1/100780 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T11:45:53Z |
| publishDate | 2016 |
| publisher | American Meteorological Society |
| record_format | dspace |
| spelling | mit-1721.1/1007802022-10-01T05:51:53Z Seasonal Variability of the Polar Stratospheric Vortex in an Idealized AGCM with Varying Tropospheric Wave Forcing Sheshadri, Aditi Plumb, R. Alan Gerber, Edwin P. Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Sheshadri, Aditi Plumb, R. Alan The seasonal variability of the polar stratospheric vortex is studied in a simplified AGCM driven by specified equilibrium temperature distributions. Seasonal variations in equilibrium temperature are imposed in the stratosphere only, enabling the study of stratosphere–troposphere coupling on seasonal time scales, without the complication of an internal tropospheric seasonal cycle. The model is forced with different shapes and amplitudes of simple bottom topography, resulting in a range of stratospheric climates. The effect of these different kinds of topography on the seasonal variability of the strength of the polar vortex, the average timing and variability in timing of the final breakup of the vortex (final warming events), the conditions of occurrence and frequency of midwinter warming events, and the impact of the stratospheric seasonal cycle on the troposphere are explored. The inclusion of wavenumber-1 and wavenumber-2 topographies results in very different stratospheric seasonal variability. Hemispheric differences in stratospheric seasonal variability are recovered in the model with appropriate choices of wave-2 topography. In the model experiment with a realistic Northern Hemisphere–like frequency of midwinter warming events, the distribution of the intervals between these events suggests that the model has no year-to-year memory. When forced with wave-1 topography, the gross features of seasonal variability are similar to those forced with wave-2 topography, but the dependence on forcing magnitude is weaker. Further, the frequency of major warming events has a nonmonotonic dependence on forcing magnitude and never reaches the frequency observed in the Northern Hemisphere. United States. National Aeronautics and Space Administration (Grant NNX13AF80G) 2016-01-10T20:39:08Z 2016-01-10T20:39:08Z 2015-06 2015-01 Article http://purl.org/eprint/type/JournalArticle 0022-4928 1520-0469 http://hdl.handle.net/1721.1/100780 Sheshadri, Aditi, R. Alan Plumb, and Edwin P. Gerber. “Seasonal Variability of the Polar Stratospheric Vortex in an Idealized AGCM with Varying Tropospheric Wave Forcing.” Journal of the Atmospheric Sciences 72, no. 6 (June 2015): 2248–2266. © 2015 American Meteorological Society https://orcid.org/0000-0002-6716-1576 https://orcid.org/0000-0002-9828-9484 en_US http://dx.doi.org/10.1175/jas-d-14-0191.1 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 | Sheshadri, Aditi Plumb, R. Alan Gerber, Edwin P. Seasonal Variability of the Polar Stratospheric Vortex in an Idealized AGCM with Varying Tropospheric Wave Forcing |
| title | Seasonal Variability of the Polar Stratospheric Vortex in an Idealized AGCM with Varying Tropospheric Wave Forcing |
| title_full | Seasonal Variability of the Polar Stratospheric Vortex in an Idealized AGCM with Varying Tropospheric Wave Forcing |
| title_fullStr | Seasonal Variability of the Polar Stratospheric Vortex in an Idealized AGCM with Varying Tropospheric Wave Forcing |
| title_full_unstemmed | Seasonal Variability of the Polar Stratospheric Vortex in an Idealized AGCM with Varying Tropospheric Wave Forcing |
| title_short | Seasonal Variability of the Polar Stratospheric Vortex in an Idealized AGCM with Varying Tropospheric Wave Forcing |
| title_sort | seasonal variability of the polar stratospheric vortex in an idealized agcm with varying tropospheric wave forcing |
| url | http://hdl.handle.net/1721.1/100780 https://orcid.org/0000-0002-6716-1576 https://orcid.org/0000-0002-9828-9484 |
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