An Analysis of 2016–18 Tornadoes and National Weather Service Tornado Warnings across the Contiguous United States
An Analysis of 2016–18 Tornadoes and National Weather Service Tornado Warnings across the Contiguous United States
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2016-18 年美国本土龙卷风和国家气象局龙卷风警报分析
DOI：
10.1175/waf-d-20-0241.1
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发表时间：
2021
影响因子：
2.9
通讯作者：
Steven E. Nelson
中科院分区：
文献类型：
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作者：
Evan S. Bentley;Richard L. Thompson;Barry R. Bowers;J. Gibbs;Steven E. Nelson
以前的工作已经考虑了龙卷风的发生与雷达数据，无论是WSR-88 D和移动的研究雷达，和一些研究已经审查的技术，以潜在地提高龙卷风预警性能。然而，迄今为止，很少有工作集中在系统的，大样本的评估国家气象局（NWS）的龙卷风警报雷达可观测的数量和近风暴环境。在这项工作中，研究了美国连续三年（2016-18年）的NWS龙卷风警报，以及警报发布前几分钟的支持数据，或在错过事件的情况下的龙卷风形成。本文的调查研究WSR-88 D和风暴预报中心（SPC）与这些龙卷风警报相关的中尺度分析数据，并与当前的警报决策培训部（WDTD）指南进行比较。结合低级别的旋转速度和显着的龙卷风参数（STP），在以前的工作中使用的，显示承诺作为一种手段来估计龙卷风预警性能，以及相对变化的性能作为标准阈值的变化。例如，在接近风暴的环境中，低水平的旋转速度峰值超过30 kt（15 m s−1），这对龙卷风来说并不是禁止的（STP > 0），与观察到的NWS龙卷风警报指标相比，这会导致检测概率的增加和误报的减少。通过在恶劣（STP = 0）环境中限制弱（<30 kt）、宽（>1 n mi; 1 n mi = 1.852 km）环流的警报，仔细消除像旁瓣污染这样的速度数据伪影，以及通过在其他可疑场景中对基于人为的龙卷风报告进行更严格的审查，也可以减少龙卷风警报误报。
Previous work has considered tornado occurrence with respect to radar data, both WSR-88D and mobile research radars, and a few studies have examined techniques to potentially improve tornado warning performance. To date, though, there has been little work focusing on systematic, large-sample evaluation of National Weather Service (NWS) tornado warnings with respect to radar-observable quantities and the near-storm environment. In this work, three full years (2016–18) of NWS tornado warnings across the contiguous United States were examined, in conjunction with supporting data in the few minutes preceding warning issuance, or tornado formation in the case of missed events. The investigation herein examines WSR-88D and Storm Prediction Center (SPC) mesoanalysis data associated with these tornado warnings with comparisons made to the current Warning Decision Training Division (WDTD) guidance. Combining low-level rotational velocity and the significant tornado parameter (STP), as used in prior work, shows promise as a means to estimate tornado warning performance, as well as relative changes in performance as criteria thresholds vary. For example, low-level rotational velocity peaking in excess of 30 kt (15 m s−1), in a near-storm environment, which is not prohibitive for tornadoes (STP > 0), results in an increased probability of detection and reduced false alarms compared to observed NWS tornado warning metrics. Tornado warning false alarms can also be reduced through limiting warnings with weak (<30 kt), broad (>1 n mi; 1 n mi = 1.852 km) circulations in a poor (STP = 0) environment, careful elimination of velocity data artifacts like sidelobe contamination, and through greater scrutiny of human-based tornado reports in otherwise questionable scenarios.