A Ventilation Index for Tropical Cyclones
An important environmental control of both tropical cyclone intensity and genesis is vertical wind shear. One hypothesized pathway by which vertical shear affects tropical cyclones is midlevel ventilation—or the flux of low-entropy air into the center of the tropical cyclone. Based on a theoretical...
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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/1721.1/79652 https://orcid.org/0000-0002-2066-2082 |
| _version_ | 1826188034088894464 |
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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 | An important environmental control of both tropical cyclone intensity and genesis is vertical wind shear. One hypothesized pathway by which vertical shear affects tropical cyclones is midlevel ventilation—or the flux of low-entropy air into the center of the tropical cyclone. Based on a theoretical framework, a ventilation index is introduced that is equal to the environmental vertical wind shear multiplied by the nondimensional midlevel entropy deficit divided by the potential intensity. The ventilation index has a strong influence on tropical cyclone climatology. Tropical cyclogenesis preferentially occurs when and where the ventilation index is anomalously low. Both the ventilation index and the tropical cyclone's normalized intensity, or the intensity divided by the potential intensity, constrain the distribution of tropical cyclone intensification. The most rapidly intensifying storms are characterized by low ventilation indices and intermediate normalized intensities, while the most rapidly weakening storms are characterized by high ventilation indices and high normalized intensities. Since the ventilation index can be derived from large-scale fields, it can serve as a simple and useful metric for operational forecasts of tropical cyclones and diagnosis of model errors. |
| first_indexed | 2024-09-23T07:53:35Z |
| format | Article |
| id | mit-1721.1/79652 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T07:53:35Z |
| publishDate | 2013 |
| publisher | American Meteorological Society |
| record_format | dspace |
| spelling | mit-1721.1/796522022-09-23T09:25:58Z A Ventilation Index for Tropical Cyclones Tang, Brian Emanuel, Kerry Andrew Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Massachusetts Institute of Technology. Program in Atmospheres, Oceans, and Climate Emanuel, Kerry Andrew An important environmental control of both tropical cyclone intensity and genesis is vertical wind shear. One hypothesized pathway by which vertical shear affects tropical cyclones is midlevel ventilation—or the flux of low-entropy air into the center of the tropical cyclone. Based on a theoretical framework, a ventilation index is introduced that is equal to the environmental vertical wind shear multiplied by the nondimensional midlevel entropy deficit divided by the potential intensity. The ventilation index has a strong influence on tropical cyclone climatology. Tropical cyclogenesis preferentially occurs when and where the ventilation index is anomalously low. Both the ventilation index and the tropical cyclone's normalized intensity, or the intensity divided by the potential intensity, constrain the distribution of tropical cyclone intensification. The most rapidly intensifying storms are characterized by low ventilation indices and intermediate normalized intensities, while the most rapidly weakening storms are characterized by high ventilation indices and high normalized intensities. Since the ventilation index can be derived from large-scale fields, it can serve as a simple and useful metric for operational forecasts of tropical cyclones and diagnosis of model errors. National Science Foundation (U.S.) (Grant ATM-0850639) 2013-07-22T17:11:17Z 2013-07-22T17:11:17Z 2012-12 2012-05 Article http://purl.org/eprint/type/JournalArticle 0003-0007 1520-0477 http://hdl.handle.net/1721.1/79652 Tang, Brian, and Kerry Emanuel. “A Ventilation Index for Tropical Cyclones.” Bulletin of the American Meteorological Society 93, no. 12 (December 2012): 1901-1912. © 2012 American Meteorological Society https://orcid.org/0000-0002-2066-2082 en_US http://dx.doi.org/10.1175/bams-d-11-00165.1 Bulletin of the American Meteorological Society 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 A Ventilation Index for Tropical Cyclones |
| title | A Ventilation Index for Tropical Cyclones |
| title_full | A Ventilation Index for Tropical Cyclones |
| title_fullStr | A Ventilation Index for Tropical Cyclones |
| title_full_unstemmed | A Ventilation Index for Tropical Cyclones |
| title_short | A Ventilation Index for Tropical Cyclones |
| title_sort | ventilation index for tropical cyclones |
| url | http://hdl.handle.net/1721.1/79652 https://orcid.org/0000-0002-2066-2082 |
| work_keys_str_mv | AT tangbrian aventilationindexfortropicalcyclones AT emanuelkerryandrew aventilationindexfortropicalcyclones AT tangbrian ventilationindexfortropicalcyclones AT emanuelkerryandrew ventilationindexfortropicalcyclones |