The Influences of Effective Inflow Layer Streamwise Vorticity and Storm-Relative Flow on Supercell Updraft Properties
The Influences of Effective Inflow Layer Streamwise Vorticity and Storm-Relative Flow on Supercell Updraft Properties
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有效流入层流向涡度和风暴相关流对超级单体上升气流特性的影响
DOI：
10.1175/jas-d-19-0355.1
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发表时间：
2020
影响因子：
3.1
通讯作者：
Thompson, Richard L.
中科院分区：
文献类型：
--
作者：
Peters, John M.;Nowotarski, Christopher J.;Mulholland, Jake P.;Thompson, Richard L.
风暴相对螺旋度（SRH）和流向涡度ω之间的关系经常被用来解释有效入流层（EIL） SRH与各种超级单体上升气流特性之间的紧密联系。然而，SRH的定义也包含风暴相对流，因此当SRH被用作诊断工具时，SRH流和ω上升气流动力学的单独影响是卷积的。为了澄清这一问题，利用近距离测深和数值实验分析了EIL SR流和ω - son超级单体上升气流特征的单独影响。我们的研究结果表明，ei ω的大小对超级细胞风暴模式是否发生影响不大。相反，从非超级单体风暴模式到超级单体风暴模式的转变在很大程度上受到EIL SR流强度的调节。此外，上升气流宽度、最大垂直速度、各级垂直质量通量和各级最大垂直涡度等许多上升气流属性在很大程度上由EIL SR流决定。对于一个恒定的EIL SR流，具有大EILω的风暴具有更强的低层净旋转和垂直速度，这证实了之前建立的ω与龙卷风形成之间的联系。ω也会影响风暴降水和冷池模式。垂直非线性动压加速度（NLDPA）在低层较大，但由于风暴中层动压扰动在很大程度上受中层涡度倾斜的影响，NLDPA在高空的差异与ei ω无关。我们的研究结果强调了在超级单体性质的研究和预测中，除了考虑EIL SRH外，还考虑EIL SR流的重要性。
The relationship between storm-relative helicity (SRH) and streamwise vorticityωsis frequently invoked to explain the often robust connections between effective inflow layer (EIL) SRH and various supercell updraft properties. However, the definition of SRH also contains storm-relative (SR) flow, and the separate influences of SR flow andωson updraft dynamics are therefore convolved when SRH is used as a diagnostic tool. To clarify this issue, proximity soundings and numerical experiments are used to disentangle the separate influences of EIL SR flow andωson supercell updraft characteristics. Our results suggest that the magnitude of EILωshas little influence on whether supercellular storm mode occurs. Rather, the transition from nonsupercellular to supercellular storm mode is largely modulated by the magnitude of EIL SR flow. Furthermore, many updraft attributes such as updraft width, maximum vertical velocity, vertical mass flux at all levels, and maximum vertical vorticity at all levels are largely determined by EIL SR flow. For a constant EIL SR flow, storms with large EILωshave stronger low-level net rotation and vertical velocities, which affirms previously established connections betweenωsand tornadogenesis. EILωsalso influences storms’ precipitation and cold-pool patterns. Vertical nonlinear dynamic pressure acceleration (NLDPA) is larger at low levels when EILωsis large, but differences in NLDPA aloft become uncorrelated with EILωsbecause storms’ midlevel dynamic pressure perturbations are substantially influenced by the tilting of midlevel vorticity. Our results emphasize the importance of considering EIL SR flow in addition to EIL SRH in the research and forecasting of supercell properties.
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影响因子：
3.1
作者：
Johannes M. L. Dahl;M. Parker;Louis J. Wicker
通讯作者：
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影响因子：
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作者：
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影响因子：
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影响因子：
3.1
作者：
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影响因子：
3.1
作者：
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