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DOI | 10.1175/JAS-D-18-0216.1 |
The Influence of Lifting Condensation Level on Low-Level Outflow and Rotation in Simulated Supercell Thunderstorms | |
Brown, Matthew; Nowotarski, Christopher J. | |
2019-05-01 | |
发表期刊 | JOURNAL OF THE ATMOSPHERIC SCIENCES |
ISSN | 0022-4928 |
EISSN | 1520-0469 |
出版年 | 2019 |
卷号 | 76期号:5页码:1349-1372 |
文章类型 | Article |
语种 | 英语 |
国家 | USA |
英文摘要 | This paper reports on results of idealized numerical simulations testing the influence of low-level humidity, and thus lifting condensation level (LCL), on the morphology and evolution of low-level rotation in supercell thunderstorms. Previous studies have shown that the LCL can influence outflow buoyancy, which can in turn affect generation and stretching of near-surface vertical vorticity. A less explored hypothesis is tested: that the LCL affects the relative positioning of near-surface circulation and the overlying mesocyclone, thus influencing the dynamic lifting and intensification of near-surface vertical vorticity. To test this hypothesis, a set of three base-state thermodynamic profiles with varying LCLs are implemented and compared over a variety of low-level wind profiles. The thermodynamic properties of the simulations are sensitive to variations in the LCL, with higher LCLs contributing to more negatively buoyant cold pools. These outflow characteristics allow for a more forward propagation of near-surface circulation relative to the midlevel mesocyclone. When the mid- and low-level mesocyclones become aligned with appreciable near-surface circulation, favorable dynamic updraft forcing is able to stretch and intensify this rotation. The strength of the vertical vorticity generated ultimately depends on other interrelated factors, including the amount of near-surface circulation generated within the cold pool and the buoyancy of storm outflow. However, these simulations suggest that mesocyclone alignment with near-surface circulation is modulated by the ambient LCL, and is a necessary condition for the strengthening of near-surface vertical vorticity. This alignment is also sensitive to the low-level wind profile, meaning that the LCL most favorable for the formation of intense vorticity may change based on ambient low-level shear properties. |
英文关键词 | Dynamics Severe storms Supercells Thermodynamics Numerical analysis modeling |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000467264300003 |
WOS关键词 | SURFACE VERTICAL VORTICITY ; REAR-FLANK DOWNDRAFTS ; PROXIMITY SOUNDINGS ; CONVECTIVE STORMS ; PART I ; TORNADOGENESIS ; ENVIRONMENTS ; SHEAR ; DOPPLER ; IMPACT |
WOS类目 | Meteorology & Atmospheric Sciences |
WOS研究方向 | Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/183023 |
专题 | 地球科学 |
作者单位 | Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA |
推荐引用方式 GB/T 7714 | Brown, Matthew,Nowotarski, Christopher J.. The Influence of Lifting Condensation Level on Low-Level Outflow and Rotation in Simulated Supercell Thunderstorms[J]. JOURNAL OF THE ATMOSPHERIC SCIENCES,2019,76(5):1349-1372. |
APA | Brown, Matthew,&Nowotarski, Christopher J..(2019).The Influence of Lifting Condensation Level on Low-Level Outflow and Rotation in Simulated Supercell Thunderstorms.JOURNAL OF THE ATMOSPHERIC SCIENCES,76(5),1349-1372. |
MLA | Brown, Matthew,et al."The Influence of Lifting Condensation Level on Low-Level Outflow and Rotation in Simulated Supercell Thunderstorms".JOURNAL OF THE ATMOSPHERIC SCIENCES 76.5(2019):1349-1372. |
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