Sensitivity of Tropical Cyclone Intensity to Ventilation in an Axisymmetric Model
The sensitivity of tropical cyclone intensity to ventilation of cooler, drier air into the inner core is examined using an axisymmetric tropical cyclone model with parameterized ventilation. Sufficiently strong ventilation induces cooling of the upper-level warm core, a shift in the secondary circul...
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| Format: | Article |
| Language: | en_US |
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American Meteorological Society
2013
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| Online Access: | http://hdl.handle.net/1721.1/77234 https://orcid.org/0000-0002-2066-2082 |
| _version_ | 1826196177774706688 |
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| author | Tang, Brian Emanuel, Kerry Andrew |
| 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 Tang, Brian Emanuel, Kerry Andrew |
| author_sort | Tang, Brian |
| collection | MIT |
| description | The sensitivity of tropical cyclone intensity to ventilation of cooler, drier air into the inner core is examined using an axisymmetric tropical cyclone model with parameterized ventilation. Sufficiently strong ventilation induces cooling of the upper-level warm core, a shift in the secondary circulation radially outward, and a decrease in the simulated intensity. Increasing the strength of the ventilation and placing the ventilation at middle to lower levels results in a greater decrease in the quasi-steady intensity, whereas upper-level ventilation has little effect on the intensity. For strong ventilation, an oscillatory intensity regime materializes and is tied to transient convective bursts and strong downdrafts into the boundary layer. The sensitivity of tropical cyclone intensity to ventilation can be viewed in the context of the mechanical efficiency of the inner core or a modified thermal wind relation. In the former, ventilation decreases the mechanical efficiency, as the generation of available potential energy is wasted by entropy mixing above the boundary layer. In the latter, ventilation weakens the eyewall entropy front, resulting in a decrease in the intensity by thermal wind arguments. The experiments also support the existence of a threshold ventilation beyond which a tropical cyclone cannot be maintained. Downdrafts overwhelm surface fluxes, leading to a precipitous drop in intensity and a severe degradation of structure in such a scenario. For a given amount of ventilation below the threshold, there exists a minimum initial intensity necessary for intensification to the quasi-steady intensity. |
| first_indexed | 2024-09-23T10:22:45Z |
| format | Article |
| id | mit-1721.1/77234 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:22:45Z |
| publishDate | 2013 |
| publisher | American Meteorological Society |
| record_format | dspace |
| spelling | mit-1721.1/772342022-09-30T20:41:32Z Sensitivity of Tropical Cyclone Intensity to Ventilation in an Axisymmetric Model Tang, Brian Emanuel, Kerry Andrew Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Emanuel, Kerry Andrew The sensitivity of tropical cyclone intensity to ventilation of cooler, drier air into the inner core is examined using an axisymmetric tropical cyclone model with parameterized ventilation. Sufficiently strong ventilation induces cooling of the upper-level warm core, a shift in the secondary circulation radially outward, and a decrease in the simulated intensity. Increasing the strength of the ventilation and placing the ventilation at middle to lower levels results in a greater decrease in the quasi-steady intensity, whereas upper-level ventilation has little effect on the intensity. For strong ventilation, an oscillatory intensity regime materializes and is tied to transient convective bursts and strong downdrafts into the boundary layer. The sensitivity of tropical cyclone intensity to ventilation can be viewed in the context of the mechanical efficiency of the inner core or a modified thermal wind relation. In the former, ventilation decreases the mechanical efficiency, as the generation of available potential energy is wasted by entropy mixing above the boundary layer. In the latter, ventilation weakens the eyewall entropy front, resulting in a decrease in the intensity by thermal wind arguments. The experiments also support the existence of a threshold ventilation beyond which a tropical cyclone cannot be maintained. Downdrafts overwhelm surface fluxes, leading to a precipitous drop in intensity and a severe degradation of structure in such a scenario. For a given amount of ventilation below the threshold, there exists a minimum initial intensity necessary for intensification to the quasi-steady intensity. National Science Foundation (U.S.) (Grant ATM-0850639) 2013-02-28T16:19:34Z 2013-02-28T16:19:34Z 2012-08 2011-09 Article http://purl.org/eprint/type/JournalArticle 0022-4928 1520-0469 http://hdl.handle.net/1721.1/77234 Tang, Brian, and Kerry Emanuel. “Sensitivity of Tropical Cyclone Intensity to Ventilation in an Axisymmetric Model.” Journal of the Atmospheric Sciences 69.8 (2012): 2394–2413. © 2012 American Meteorological Society https://orcid.org/0000-0002-2066-2082 en_US http://dx.doi.org/10.1175/jas-d-11-0232.1 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 | Tang, Brian Emanuel, Kerry Andrew Sensitivity of Tropical Cyclone Intensity to Ventilation in an Axisymmetric Model |
| title | Sensitivity of Tropical Cyclone Intensity to Ventilation in an Axisymmetric Model |
| title_full | Sensitivity of Tropical Cyclone Intensity to Ventilation in an Axisymmetric Model |
| title_fullStr | Sensitivity of Tropical Cyclone Intensity to Ventilation in an Axisymmetric Model |
| title_full_unstemmed | Sensitivity of Tropical Cyclone Intensity to Ventilation in an Axisymmetric Model |
| title_short | Sensitivity of Tropical Cyclone Intensity to Ventilation in an Axisymmetric Model |
| title_sort | sensitivity of tropical cyclone intensity to ventilation in an axisymmetric model |
| url | http://hdl.handle.net/1721.1/77234 https://orcid.org/0000-0002-2066-2082 |
| work_keys_str_mv | AT tangbrian sensitivityoftropicalcycloneintensitytoventilationinanaxisymmetricmodel AT emanuelkerryandrew sensitivityoftropicalcycloneintensitytoventilationinanaxisymmetricmodel |