Investigating the relationship between polarimetric radar signatures of hydrometeor size sorting and tornadic potential in simulated supercells
Investigating the relationship between polarimetric radar signatures of hydrometeor size sorting and tornadic potential in simulated supercells
复制标题
研究模拟超级单体中水凝物尺寸分类的偏振雷达特征与龙卷势之间的关系
DOI：
10.1175/mwr-d-22-0228.1
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发表时间：
2023
影响因子：
3.2
通讯作者：
Parker, Matthew D.
中科院分区：
文献类型：
--
作者：
Loeffler, Scott D.;Kumjian, Matthew R.;Markowski, Paul M.;Coffer, Brice E.;Parker, Matthew D.
国家对业务天气雷达网络进行升级，以包括极化能力，这导致了许多研究，重点是在超级单体中通常观察到的极化雷达特征。一个这样的签名是由于水凝物尺寸分选而导致的增强差分反射率（ZDR）和特定差分相位（KDP）值的区域的水平分离。最近的观测研究表明，这种分离的方向往往更垂直于产生龙卷风的超级单体中的风暴运动。虽然这一发现具有潜在的业务效用，但这一观测到的雷达信号与龙卷风势之间的物理关系尚不清楚。本研究使用了一个合奏的超细胞模拟初始化与tornadic和nontornadic环境，调查这种连接。尽管程度较低，但龙卷风超晶胞具有更垂直的分离取向的趋势得到了再现。这种方向角的差异是由于非龙卷风超级单体中较强的向后风暴相对流造成的，导致降水向后移动，因此，超级单体中的增强KDP区域。此外，这导致了不利的负浮力区的向后移动，这导致了一个数量级的斜压产生的环流相比，龙卷风模拟在非龙卷风模拟。
The national upgrade of the operational weather radar network to include polarimetric capabilities has led to numerous studies focusing on polarimetric radar signatures commonly observed in supercells. One such signature is the horizontal separation of regions of enhanced differential reflectivity (ZDR) and specific differential phase (KDP) values due to hydrometeor size sorting. Recent observational studies have shown that the orientation of this separation tends to be more perpendicular to storm motion in supercells that produce tornadoes. Although this finding has potential operational utility, the physical relationship between this observed radar signature and tornadic potential is not known. This study uses an ensemble of supercell simulations initialized with tornadic and nontornadic environments to investigate this connection. The tendency for tornadic supercells to have a more perpendicular separation orientation was reproduced, although to a lesser degree. This difference in orientation angles was caused by stronger rearward storm-relative flow in the nontornadic supercells, leading to a rearward shift of precipitation and, therefore, the enhancedKDPregion within the supercell. Further, this resulted in an unfavorable rearward shift of the negative buoyancy region, which led to an order of magnitude less baroclinic generation of circulation in the nontornadic simulations compared to tornadic simulations.