{"title":"Minimal conceptual models for tropical cyclone intensification","authors":"Michael T. Montgomery , Roger K. Smith","doi":"10.1016/j.tcrr.2022.06.002","DOIUrl":null,"url":null,"abstract":"<div><p>We examine a hierarchy of minimal conceptual models for tropical cyclone intensification. These models are framed mostly in terms of axisymmetric balance dynamics. In the first set of models, the heating rate is prescribed in such a way to mimic a deep overturning circulation with convergence in the lower troposphere and divergence in the upper troposphere, characteristic of a region of deep moist convection. In the second set, the heating rate is related explicitly to the latent heat release of ascending air parcels. The release of latent heat markedly reduces the local static stability of ascending air, raising two possibilities in the balance framework. The first possibility is that the effective static stability and the related discriminant in the Eliassen equation for the overturning circulation in saturated air, although small, remains positive so the Eliassen equation is globally elliptic. The second possibility, the more likely one during vortex intensification, is that the effective static stability in saturated air is negative and the Eliassen equation becomes locally hyperbolic. These models help to understand the differences between the early Ooyama models of 1968 and 1969, the Emanuel, 1989 model, and the later Emanuel models of 1995, 1997 and 2012. They provide insight also into the popular explanation of the WISHE feedback mechanism for tropical cyclone intensification. Some implications for recent work are discussed.</p></div>","PeriodicalId":44442,"journal":{"name":"Tropical Cyclone Research and Review","volume":"11 2","pages":"Pages 61-75"},"PeriodicalIF":2.4000,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2225603222000121/pdfft?md5=3a82980019123738bb0bae5f2e870a1f&pid=1-s2.0-S2225603222000121-main.pdf","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Tropical Cyclone Research and Review","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2225603222000121","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"METEOROLOGY & ATMOSPHERIC SCIENCES","Score":null,"Total":0}
引用次数: 2
Abstract
We examine a hierarchy of minimal conceptual models for tropical cyclone intensification. These models are framed mostly in terms of axisymmetric balance dynamics. In the first set of models, the heating rate is prescribed in such a way to mimic a deep overturning circulation with convergence in the lower troposphere and divergence in the upper troposphere, characteristic of a region of deep moist convection. In the second set, the heating rate is related explicitly to the latent heat release of ascending air parcels. The release of latent heat markedly reduces the local static stability of ascending air, raising two possibilities in the balance framework. The first possibility is that the effective static stability and the related discriminant in the Eliassen equation for the overturning circulation in saturated air, although small, remains positive so the Eliassen equation is globally elliptic. The second possibility, the more likely one during vortex intensification, is that the effective static stability in saturated air is negative and the Eliassen equation becomes locally hyperbolic. These models help to understand the differences between the early Ooyama models of 1968 and 1969, the Emanuel, 1989 model, and the later Emanuel models of 1995, 1997 and 2012. They provide insight also into the popular explanation of the WISHE feedback mechanism for tropical cyclone intensification. Some implications for recent work are discussed.
期刊介绍:
Tropical Cyclone Research and Review is an international journal focusing on tropical cyclone monitoring, forecasting, and research as well as associated hydrological effects and disaster risk reduction. This journal is edited and published by the ESCAP/WMO Typhoon Committee (TC) and the Shanghai Typhoon Institute of the China Meteorology Administration (STI/CMA). Contributions from all tropical cyclone basins are welcome.
Scope of the journal includes:
• Reviews of tropical cyclones exhibiting unusual characteristics or behavior or resulting in disastrous impacts on Typhoon Committee Members and other regional WMO bodies
• Advances in applied and basic tropical cyclone research or technology to improve tropical cyclone forecasts and warnings
• Basic theoretical studies of tropical cyclones
• Event reports, compelling images, and topic review reports of tropical cyclones
• Impacts, risk assessments, and risk management techniques related to tropical cyclones