Long-Term Performance Metrics for National Weather Service Tornado Warnings
Long-Term Performance Metrics for National Weather Service Tornado Warnings
复制标题
国家气象局龙卷风警报的长期绩效指标
DOI：
10.1175/waf-d-18-0120.1
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发表时间：
2018
影响因子：
2.9
通讯作者：
J. Correia
中科院分区：
文献类型：
--
作者：
H. Brooks;J. Correia
龙卷风警报是美国国家气象局的旗舰产品之一。我们更新各种绩效指标的时间序列，以便提供1986-2016年期间的交付期、检测概率、虚警率和警告持续时间的基线。我们使用了指标(龙卷风的平均提前时间，龙卷风提前预警的比例)，这些指标在发布预警的官方政策变化以及非官方变化发生的时间点上以一致的方式发挥作用。从1986年到2011年，龙卷风预警的平均提前时间相对恒定，而龙卷风预警的比例在2006年左右有所增加，虚警率缓慢下降。性能的最大变化发生在2012年，当时默认警告持续时间减少，而且显然更加重视减少错误警报。因此，2012年的交付期、检测概率和误警率都有所下降。
我们的分析在很大程度上是基于信号检测理论，该理论将警报系统的质量与发出警报的阈值分开。阈值更改会导致在错误警报和漏检之间进行权衡。这些变化为整个预警系统认为重要的内容的变化提供了进一步的证据，并突显了通过独立查看指标来衡量业绩的局限性。
Tornado warnings are one of the flagship products of the National Weather Service. We update the time series of various metrics of performance in order to provide baselines over the 1986–2016 period for lead time, probability of detection, false alarm ratio, and warning duration. We have used metrics (mean lead time for tornadoes warned in advance, fraction of tornadoes warned in advance) that work in a consistent way across the official changes in policy for warning issuance, as well as across points in time when unofficial changes took place. The mean lead time for tornadoes warned in advance was relatively constant from 1986 to 2011, while the fraction of tornadoes warned in advance increased through about 2006, and the false alarm ratio slowly decreased. The largest changes in performance take place in 2012 when the default warning duration decreased, and there is an apparent increased emphasis on reducing false alarms. As a result, the lead time, probability of detection, and false alarm ratio all decrease in 2012.
Our analysis is based, in large part, on signal detection theory, which separates the quality of the warning system from the threshold for issuing warnings. Threshold changes lead to trade-offs between false alarms and missed detections. Such changes provide further evidence for changes in what the warning system as a whole considers important, as well as highlighting the limitations of measuring performance by looking at metrics independently.