The Diabatic Rossby Vortex: Growth Rate, Length Scale, and the Wave–Vortex Transition
<jats:title>Abstract</jats:title> <jats:p>In idealized simulations of moist baroclinic instability on a sphere, the most unstable mode transitions from a periodic wave to an isolated vortex in sufficiently warm climates. The vortex mode is maintained through latent heating and sho...
| Main Authors: | , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
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American Meteorological Society
2023
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| Online Access: | https://hdl.handle.net/1721.1/148139 |
| _version_ | 1826215584678805504 |
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| author | Kohl, Matthieu O’Gorman, Paul A |
| 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 Kohl, Matthieu O’Gorman, Paul A |
| author_sort | Kohl, Matthieu |
| collection | MIT |
| description | <jats:title>Abstract</jats:title>
<jats:p>In idealized simulations of moist baroclinic instability on a sphere, the most unstable mode transitions from a periodic wave to an isolated vortex in sufficiently warm climates. The vortex mode is maintained through latent heating and shows the principal characteristics of a diabatic Rossby vortex (DRV) that has been found in a range of different simulations and observations of the current climate. Currently, there is no analytical theory for DRVs or understanding of the wave–vortex transition that has been found in warmer climates. Here, we introduce a minimal moist two-layer quasigeostrophic model with tilted boundaries capable of producing a DRV mode, and we derive growth rates and length scales for this DRV mode. In the limit of a convectively neutral stratification, the length scale of ascent of the DRV is the same as that of a periodic moist baroclinic wave, but the growth rate of the DRV is 54% faster. We explain the isolated structure of the DRV using a simple potential vorticity (PV) argument, and we create a phase diagram for when the most unstable solution is a periodic wave versus a DRV, with the DRV emerging when the moist static stability and meridional PV gradients are weak. Last, we compare the structure of the DRV mode with DRV storms found in reanalysis and with a DRV storm in a warm-climate simulation.</jats:p>
<jats:sec>
<jats:title>Significance Statement</jats:title>
<jats:p>Past research has identified a special class of midlatitude storm, dubbed the diabatic Rossby vortex (DRV), which derives its energy from the release of latent heat associated with condensation of water vapor and as such goes beyond the traditional understanding of midlatitude storm formation. DRVs have been implicated in extreme and poorly predicted forms of cyclogenesis along the east coast of the United States and the west coast of Europe with significant damage to property and human life. The purpose of this study is to develop a mathematical theory for the intensification rate and length scale of DRVs to gain a deeper understanding of the dynamics of these storms in current and future climates.</jats:p></jats:sec> |
| first_indexed | 2024-09-23T16:36:04Z |
| format | Article |
| id | mit-1721.1/148139 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T16:36:04Z |
| publishDate | 2023 |
| publisher | American Meteorological Society |
| record_format | dspace |
| spelling | mit-1721.1/1481392023-04-08T03:58:04Z The Diabatic Rossby Vortex: Growth Rate, Length Scale, and the Wave–Vortex Transition Kohl, Matthieu O’Gorman, Paul A Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences <jats:title>Abstract</jats:title> <jats:p>In idealized simulations of moist baroclinic instability on a sphere, the most unstable mode transitions from a periodic wave to an isolated vortex in sufficiently warm climates. The vortex mode is maintained through latent heating and shows the principal characteristics of a diabatic Rossby vortex (DRV) that has been found in a range of different simulations and observations of the current climate. Currently, there is no analytical theory for DRVs or understanding of the wave–vortex transition that has been found in warmer climates. Here, we introduce a minimal moist two-layer quasigeostrophic model with tilted boundaries capable of producing a DRV mode, and we derive growth rates and length scales for this DRV mode. In the limit of a convectively neutral stratification, the length scale of ascent of the DRV is the same as that of a periodic moist baroclinic wave, but the growth rate of the DRV is 54% faster. We explain the isolated structure of the DRV using a simple potential vorticity (PV) argument, and we create a phase diagram for when the most unstable solution is a periodic wave versus a DRV, with the DRV emerging when the moist static stability and meridional PV gradients are weak. Last, we compare the structure of the DRV mode with DRV storms found in reanalysis and with a DRV storm in a warm-climate simulation.</jats:p> <jats:sec> <jats:title>Significance Statement</jats:title> <jats:p>Past research has identified a special class of midlatitude storm, dubbed the diabatic Rossby vortex (DRV), which derives its energy from the release of latent heat associated with condensation of water vapor and as such goes beyond the traditional understanding of midlatitude storm formation. DRVs have been implicated in extreme and poorly predicted forms of cyclogenesis along the east coast of the United States and the west coast of Europe with significant damage to property and human life. The purpose of this study is to develop a mathematical theory for the intensification rate and length scale of DRVs to gain a deeper understanding of the dynamics of these storms in current and future climates.</jats:p></jats:sec> 2023-02-21T19:50:05Z 2023-02-21T19:50:05Z 2022 2023-02-21T19:47:00Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/148139 Kohl, Matthieu and O’Gorman, Paul A. 2022. "The Diabatic Rossby Vortex: Growth Rate, Length Scale, and the Wave–Vortex Transition." Journal of the Atmospheric Sciences, 79 (10). en 10.1175/JAS-D-22-0022.1 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 (AMS) |
| spellingShingle | Kohl, Matthieu O’Gorman, Paul A The Diabatic Rossby Vortex: Growth Rate, Length Scale, and the Wave–Vortex Transition |
| title | The Diabatic Rossby Vortex: Growth Rate, Length Scale, and the Wave–Vortex Transition |
| title_full | The Diabatic Rossby Vortex: Growth Rate, Length Scale, and the Wave–Vortex Transition |
| title_fullStr | The Diabatic Rossby Vortex: Growth Rate, Length Scale, and the Wave–Vortex Transition |
| title_full_unstemmed | The Diabatic Rossby Vortex: Growth Rate, Length Scale, and the Wave–Vortex Transition |
| title_short | The Diabatic Rossby Vortex: Growth Rate, Length Scale, and the Wave–Vortex Transition |
| title_sort | diabatic rossby vortex growth rate length scale and the wave vortex transition |
| url | https://hdl.handle.net/1721.1/148139 |
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