Exploring Tornadic Debris Signature Hypotheses Using Radar Simulations and Large-Eddy Simulations
Exploring Tornadic Debris Signature Hypotheses Using Radar Simulations and Large-Eddy Simulations
复制标题
使用雷达模拟和大涡模拟探索龙卷碎片特征假设
DOI：
10.1175/jtech-d-22-0141.1
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发表时间：
2023
影响因子：
2.2
通讯作者：
Maruyama, Takashi
中科院分区：
文献类型：
--
作者：
Cross, Rachael N.;Bodine, David J.;Palmer, Robert D.;Griffin, Casey;Cheong, Boonleng;Torres, Sebastian;Fulton, Caleb;Lujan, Javier;Maruyama, Takashi
当龙卷风将碎片抛到雷达波束的高度时，有时可以在雷达上观察到一个被称为龙卷风碎片特征（TDS）的特征。TDS对业务预报员来说是一个有用的信号，因为它可以确认龙卷风的存在，并提供有关所发生损失的信息。由于对龙卷风强度的实时估计并不具有高度的准确性，过去的研究假设TDS也可以是龙卷风强度的指标。然而，很少有研究相关的龙卷风风场的TDS特性，因为很难获得准确的，三维的风数据在龙卷风的雷达数据。考虑到这一点，本研究的目标有两个：1）调查TDS的偏振特性与三维龙卷风之间的关系，2）确定偏振雷达变量与碎片特性之间的关系。使用一个双极化雷达模拟器称为SimRadar进行模拟;龙卷风的大涡模拟（LES）;和一个单卷，矩阵为基础的仿真器。结果表明，对于所有模拟的碎片类型，水平和垂直风速的增加与相关系数的降低以及TDS面积和高度的增加有关，相反，水平和垂直风速的降低与相关系数的增加有关。TDS面积和高度的减少。然而，相关系数值的范围因碎片类型而异，这表明由类似碎片类型组成的TDS与散射体不同的TDS相比，在雷达上看起来可能大不相同。这些发现证实了过去的观测假设，可以帮助业务预报员进行龙卷风探测，并可能使用雷达数据对损害严重程度进行分类。
When a tornado lofts debris to the height of the radar beam, a signature known as the tornadic debris signature (TDS) can sometimes be observed on radar. The TDS is a useful signature for operational forecasters because it can confirm the presence of a tornado and provide information about the amount of damage occurring. Since real-time estimates of tornadic intensity do not have a high degree of accuracy, past studies have hypothesized that the TDS could also be an indicator of the strength of a tornado. However, few studies have related the tornadic wind field to TDS characteristics because of the difficulty of obtaining accurate, three-dimensional wind data in tornadoes from radar data. With this in mind, the goals of this study are twofold: 1) to investigate the relationships between polarimetric characteristics of TDSs and the three-dimensional tornadic winds, and 2) to define relationships between polarimetric radar variables and debris characteristics. Simulations are performed using a dual-polarization radar simulator called SimRadar; large-eddy simulations (LESs) of tornadoes; and a single-volume,-matrix-based emulator. Results show that for all simulated debris types increases in horizontal and vertical wind speeds are related to decreases in correlation coefficient and increases in TDS area and height and that, conversely, decreases in horizontal and vertical wind speeds are related to increases in correlation coefficient and decreases in TDS area and height. However, the range of correlation coefficient values varies with debris type, indicating that TDSs that are composed of similar debris types can appear remarkably different on radar in comparison with a TDS with diverse scatterers. Such findings confirm past observational hypotheses and can aid operational forecasters in tornado detection and potentially the categorization of damage severity using radar data.