Worldwide urbanization has resulted in more hot extremes in urban areas than surrounding rural areas. Most studies focused on the contribution of urbanization to daytime hot extremes (DayHot), while the contribution to compound hot extremes (CoHot) that considers the concurrence of both daytime and nighttime heat is less understood. Here, we quantify the urbanization contributions across the world by comparing the characteristics of hot extremes between urban and rural areas from 3,401 meteorological stations classified by 30-m resolution impervious area data. We find more significant increases in frequency, duration, and intensity of CoHot over most urban stations, where urbanization contributes to 12.5%, 15.4%, and 16.7% of the increases, respectively. Urbanization also contributes to the increase in frequency of DayHot, but has weaker impacts on the duration and intensity of Dayhot. This study implies that urbanization effects on the characteristics of hot extremes might be underestimated if only considers DayHot.

中文翻译：

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全球城市化导致夏季复合高温极端天气更持久

全球城市化导致城市地区比周边农村地区更热。大多数研究都集中在城市化对白天极端高温 (DayHot) 的贡献上，而对考虑白天和夜间高温同时发生的复合极端高温 (CoHot) 的贡献则知之甚少。在这里，我们通过比较由 30 米分辨率不透水区数据分类的 3,401 个气象站的城市和农村地区极端炎热的特征来量化世界各地的城市化贡献。我们发现，在大多数城市站点上，CoHot 的频率、持续时间和强度都有更显着的增加，其中城市化分别贡献了 12.5%、15.4% 和 16.7% 的增加。城市化也促进了 DayHot 频率的增加，但对白昼持续时间和强度的影响较小。该研究表明，如果仅考虑 DayHot，城市化对极端炎热天气特征的影响可能会被低估。