Evaluating high-impact precipitation forecasts from the Met Office Global Hazard Map using a global impact database: Impact-based evaluation of global high-impact precipitation forecasts
Evaluating high-impact precipitation forecasts from the Met Office Global Hazard Map using a global impact database: Impact-based evaluation of global high-impact precipitation forecasts
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使用全球影响数据库评估英国气象局全球灾害地图的高影响降水预报：基于影响的全球高影响降水预报评估
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
J. C. R. H. A. Titley
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文献类型：
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作者：
J. C. R. H. A. Titley
通信j.c.罗宾斯，天气影响小组，气象局，埃克塞特，英国。电子邮件：joanne.robbins@metoffice.gov.uk英国气象局全球灾害地图（GHM）利用全球综合预报数据总结了未来一周全球范围内高影响天气的风险。除了网格化的每日概率预报外，基于符号和多边形的摘要层还提供了未来一周可能的高影响天气的概览。为了评估GHM的性能，我们使用了两种互补的方法。第一种是比较日格点降水预报与全球降水观测的客观降水验证方法。其次，本文的主要焦点是一种新的半自动化评估方法，该方法评估了多模式集合降水汇总层突出引起社区影响的事件的能力，这些事件记录在影响数据库中。对实测降水的验证证实了降水预报具有较好的技巧，多模式集合对推进到汇总层提供了最好的指导。对影响的验证表明，全球温室效应降水预报与全球强降雨影响之间存在良好的空间关系。在1-3天内，所有冲击严重程度的命中率从40%到60%不等，在较长的前置时间内，命中率逐渐降低（6-7天为10-20%）。与低、中、灾难性影响事件类别相比，高影响事件的捕获程度略低，本文阐述了一些可能积极改变撞击率曲线轮廓的方法。
Correspondence J. C. Robbins, Weather Impacts Team, Met Office, Exeter, UK. Email: joanne.robbins@metoffice.gov.uk The Met Office Global Hazard Map (GHM) summarizes the risk of high-impact weather across the globe over the coming week using global ensemble forecast data. In addition to gridded daily probability forecasts, a symbol and polygon-based summary layer gives an at-a-glance view of likely high-impact weather for the week ahead. To evaluate the performance of the GHM, two complementary approaches were used. The first is an objective precipitation verification approach comparing the daily gridded precipitation forecasts with global precipitation observations. The second, and the main focus of this paper is a new, semi-automated evaluation approach that assesses the ability of the multi-model ensemble precipitation summary layer to highlight events that cause community impacts, as recorded in an impact database. The verification against observed precipitation confirms there is good skill in the precipitation forecasts and that the multi-model ensemble provides the best guidance to take forward into the summary layer. The verification against impacts indicates there is a good spatial relationship between the GHM precipitation forecasts and heavy rainfall impacts across the globe. Hit rates for all impact severities range from 40 to 60% for days 1–3 and taper off to lower hit rates at the longer lead times (10–20% for days 6–7). High-impact events are captured marginally less well than the low-, mediumand disastrous-impact event categories and this paper illustrates a number of approaches that could positively alter the profile of the hit-rate curve.