Three-Dimensional Storm Structure and Low-Level Boundaries at Different Stages of Cyclic Mesocyclone Evolution in a High-Precipitation Tornadic Supercell
Three-Dimensional Storm Structure and Low-Level Boundaries at Different Stages of Cyclic Mesocyclone Evolution in a High-Precipitation Tornadic Supercell
复制标题
高降水超级单体旋回中气旋演化不同阶段的三维风暴结构和低层边界
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
C. Ziegler
中科院分区：
文献类型：
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作者：
D. Betten;M. Biggerstaff;C. Ziegler
在龙卷风高降水超级单体的多个中气旋循环期间，每三分钟进行一次前所未有的90分钟的近乎连续的风检索。渐近收缩率分析揭示了主、次后翼阵风锋（RFGF和SRFGF）与后翼下沉气流（RFD）和遮挡下沉气流之间的关系。这被认为是第一个基于雷达的分析，近地面阵风锋和他们的父母下降气流之间的关系已被探索为连续的中气旋。SRFGF的变化与RFD的激增相关。在中气旋生命周期的一部分，SRFG产生了一个带的低层辐合和相关的深上升气流沿沿着西南侧的钩状回波区，摄入RFD外流和限制夹带到RFD和加强低层辐合沿着的主要RFGF的前缘。第二个中气旋加强从闭塞上升气流，而不是在主上升气流拉伸。这个低层中气旋与上升气流切变区涡度保持良好的分离，而上升气流切变区涡度与更传统的中层中气旋有关。然而，第三个中气旋开始在初级上升气流区的涡度丰富的区域，并扩大了在初级上升气流的拉伸。
Nearly continuous wind retrievals every three minutes for an unprecedented 90-minute period were constructed during multiple mesocyclone cycles in a tornadic high-precipitation supercell. Asymptotic contraction rate analysis revealed the relationship between the primary and secondary rear-flank gust fronts (RFGF and SRFGFs) and the rear-flank downdraft (RFD) and occlusion downdrafts. This is thought to be the first radar-based analysis where the relationship between the near-surface gust fronts and their parent downdrafts has been explored for sequential mesocyclones. Changes in the SRFGFs were associated with surges in the RFD. During part of the mesocyclone lifecycle, the SRFGF produced a band of low-level convergence and associated deep updraft along the southwestern side of the hook echo region that ingested the RFD outflow and limited both entrainment into the RFD and reinforcement of low-level convergence along the leading edge of the primary RFGF. The second mesocyclone intensified from stretching in an occlusion updraft rather than in the primary updraft. This low-level mesocyclone remained well separated from the updraft shear region vorticity that was associated with a more traditional midlevel mesocyclone. However, the third mesocyclone initiated in the vorticity-rich region of the primary updraft zone and was amplified by stretching in the primary updraft.