A Vortical Hot Tower Route to Tropical Cyclogenesis.
A Vortical Hot Tower Route to Tropical Cyclogenesis.
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DOI：
10.1175/jas3604.1
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发表时间：
2006
影响因子：
3.1
通讯作者：
M. Montgomery;M. Nicholls;Thomas A. Cram;A. B. Saunders
中科院分区：
文献类型：
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作者：
M. Montgomery;M. Nicholls;Thomas A. Cram;A. B. Saunders
摘要：一个非静力云模式被用于在实际气象条件下研究热带气旋生成的热动力学。观测促使我们关注这样一个问题：在热带海洋夏季条件下，中尺度对流系统经常产生的对流层中层气旋性涡旋如何可能转变为一个集中在近地面的（暖心）热带低压。作为第一步，在没有垂直风切变或纬向气流的情况下研究涡旋转变。在中尺度对流涡旋（MCV）胚胎富含气旋性涡度的环境中，模拟表明，在其核心具有强烈气旋性涡度的小尺度积雨云塔[涡旋热塔（VHTs）]作为首选的相干结构出现。涡旋热塔通过中尺度对流涡旋水平涡度的倾斜以及中尺度对流涡旋和涡旋热塔产生的垂直涡度的拉伸相结合的方式获得其垂直涡度。水平局域化并表现出对流……
Abstract A nonhydrostatic cloud model is used to examine the thermomechanics of tropical cyclogenesis under realistic meteorological conditions. Observations motivate the focus on the problem of how a midtropospheric cyclonic vortex, a frequent by-product of mesoscale convective systems during summertime conditions over tropical oceans, may be transformed into a surface-concentrated (warm core) tropical depression. As a first step, the vortex transformation is studied in the absence of vertical wind shear or zonal flow. Within the cyclonic vorticity-rich environment of the mesoscale convective vortex (MCV) embryo, the simulations demonstrate that small-scale cumulonimbus towers possessing intense cyclonic vorticity in their cores [vortical hot towers (VHTs)] emerge as the preferred coherent structures. The VHTs acquire their vertical vorticity through a combination of tilting of MCV horizontal vorticity and stretching of MCV and VHT-generated vertical vorticity. Horizontally localized and exhibiting conve...