Department of Urban Design and Planning, University of Washington, Seattle, WA, USA.
Department of Emergency Management, Jacksonville State University, Anniston, AL, USA.
Risk Anal. 2019 Jan;39(1):274-290. doi: 10.1111/risa.12896. Epub 2017 Nov 9.
The National Weather Service has adopted warning polygons that more specifically indicate the risk area than its previous county-wide warnings. However, these polygons are not defined in terms of numerical strike probabilities (p ). To better understand people's interpretations of warning polygons, 167 participants were shown 23 hypothetical scenarios in one of three information conditions-polygon-only (Condition A), polygon + tornadic storm cell (Condition B), and polygon + tornadic storm cell + flanking nontornadic storm cells (Condition C). Participants judged each polygon's p and reported the likelihood of taking nine different response actions. The polygon-only condition replicated the results of previous studies; p was highest at the polygon's centroid and declined in all directions from there. The two conditions displaying storm cells differed from the polygon-only condition only in having p just as high at the polygon's edge nearest the storm cell as at its centroid. Overall, p values were positively correlated with expectations of continuing normal activities, seeking information from social sources, seeking shelter, and evacuating by car. These results indicate that participants make more appropriate p judgments when polygons are presented in their natural context of radar displays than when they are presented in isolation. However, the fact that p judgments had moderately positive correlations with both sheltering (a generally appropriate response) and evacuation (a generally inappropriate response) suggests that experiment participants experience the same ambivalence about these two protective actions as people threatened by actual tornadoes.
美国国家气象局采用了预警多边形，这些多边形比之前的全县范围预警更具体地指示了风险区域。然而，这些多边形不是用数值击中点概率（p）来定义的。为了更好地理解人们对预警多边形的解释，167 名参与者在三种信息条件下展示了 23 个假设场景——仅多边形（条件 A）、多边形+龙卷风暴细胞（条件 B）和多边形+龙卷风暴细胞+侧翼非龙卷风暴细胞（条件 C）。参与者判断每个多边形的 p 值，并报告了采取九种不同反应行动的可能性。仅多边形条件复制了先前研究的结果；p 值在多边形的质心处最高，并从那里向各个方向递减。显示风暴细胞的两个条件与仅多边形条件的不同之处仅在于，在离风暴细胞最近的多边形边缘处的 p 值与质心处的 p 值一样高。总体而言，p 值与继续正常活动、从社交来源获取信息、寻求庇护和驾车撤离呈正相关。这些结果表明，当多边形在雷达显示的自然环境中呈现时，参与者对 p 值的判断比在孤立状态下更准确。然而，p 值判断与避难（一种通常适当的反应）和疏散（一种通常不适当的反应）都有中度正相关，这表明实验参与者对这两种保护措施同样存在矛盾，就像实际受到龙卷风威胁的人一样。
