The Numerical Simulation of Non-Supercell Tornadogenesis. Part I: Initiation and Evolution of Pretornadic Misocyclone Circulations along a Dry Outflow Boundary
The Numerical Simulation of Non-Supercell Tornadogenesis. Part I: Initiation and Evolution of Pretornadic Misocyclone Circulations along a Dry Outflow Boundary
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非超细胞龙卷发生的数值模拟。
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
R. Wilhelmson
中科院分区：
文献类型：
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作者：
Bruce D. Lee;R. Wilhelmson
摘要 高分辨率三维模拟用于研究沿着流出边界前缘的米索旋风的产生和发展。模型条件的设计使得这种发展可以独立于潮湿过程进行模拟。流出边界被允许传播到南侧低层流区域，从而导致沿着流出前缘的垂直涡片。随后出现波瓣和裂隙不稳定性，并为水平剪切不稳定性的后续发展提供扰动。这些不断增长的不稳定性是波长范围为 1.6 至 3.2 公里的前缘米索气旋的初始环流。这些模拟的米索旋风的结构与沿科罗拉多州东北部流出边界观测到的风前米索旋风相比更为有利。据观察，涡流片动力学对不断演变的流出前缘的结构施加实质性控制。垂直涡流片通过离散演化...
Abstract High-resolution three-dimensional simulations are used to study misocyclone initiation and development along the leading edge of an outflow boundary. Model conditions were designed such that this development could be simulated independent of moist processes. The outflow boundary is allowed to propagate into a region of southerly low-level flow which results in a vertical vortex sheet along the outflow’s leading edge. Lobe and cleft instabilities follow and provide perturbations for the subsequent development of horizontal shearing instabilities. These growing instabilities are the inaugural circulations of leading edge misocyclones with wavelengths ranging from 1.6 to 3.2 km. The structure of these modeled misocyclones compares favorably to observed pretornadic misocyclones along outflow boundaries in northeast Colorado. Vortex sheet dynamics are observed to exert substantial control over the structure of the evolving outflow leading edge. The vertical vortex sheet passes through discrete evoluti...