Polarimetric Radar Observations at Low Levels during Tornado Life Cycles in a Small Sample of Classic Southern Plains Supercells
Polarimetric Radar Observations at Low Levels during Tornado Life Cycles in a Small Sample of Classic Southern Plains Supercells
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经典南部平原超级单体小样本中龙卷风生命周期期间低水平的偏振雷达观测
DOI：
10.1175/2007jamc1714.1
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发表时间：
2008
影响因子：
3
通讯作者：
E. Rasmussen
中科院分区：
文献类型：
--
作者：
M. V. Broeke;J. Straka;E. Rasmussen
摘要本文通过对南方平原少量典型超级单体的分析，初步得到了典型超级单体在龙卷风前、龙卷风和龙卷风消亡时间的极化特征图。识别了反射率因子（ZHH）、差分反射率（ZDR）、相关系数（ρhv）和特定差分相位（KDP）的特征特征和模式。还讨论了可能与正在进行的龙卷风有关的签名。在龙卷风时期，ZHH的主要发现包括高值的“翅膀”通常从上升气流区向外延伸，在回波附属物的西侧有一个更强的梯度，在有利于龙卷风形成的风暴位置有一个局部极大值。在整个龙卷风生命周期中，钩回波区气旋曲率增加。ZDR往往在龙卷风时期最常显示冰雹轴，最高的风暴值通常位于风暴的前缘。
Abstract Preliminary schematics of polarimetric signatures at low levels in southern plains classic supercells are developed for pretornado, tornado, and tornado demise times from a small collection of cases, most of which are cyclic tornado producers. Characteristic signatures and patterns are identified for the reflectivity factor (ZHH), the differential reflectivity (ZDR), the correlation coefficient (ρhv), and the specific differential phase (KDP). Signatures likely related to an ongoing tornado are also discussed. Major findings in ZHH at tornado times include “wings” of higher values often extending away from the updraft region, a stronger gradient on the west side of the echo appendage, and a local maximum at the storm location favorable for tornadogenesis. Increasing cyclonic curvature of the hook-echo region was noted through the tornado life cycle. The ZDR tended to indicate hail shafts most commonly at tornado times, with the highest storm values typically located along the storm’s forward flan...