Magnitude of urban heat islands largely explained by climate and population
Magnitude of urban heat islands largely explained by climate and population
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DOI：
10.1038/s41586-019-1512-9
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发表时间：
2019-09-05
期刊：
影响因子：
64.8
通讯作者：
Bou-Zeid, Elie
中科院分区：
文献类型：
--
作者：
Manoli, Gabriele;Fatichi, Simone;Bou-Zeid, Elie
城市热岛（UHI）加剧了与全球气候变化相关的热相关死亡风险。城市热岛的强度随人口规模和年平均降水量的不同而变化，但缺乏对这种变化的统一解释，也没有针对地理的缓解炎热的指南。在这里，我们分析了夏季全球城市和农村地表温度 (Delta T-s) 之间的差异，发现 Delta T-s 随降水量呈非线性增加，该增加受水或蒸散能量限制的控制，并调节 Delta T-s 随城市规模的变化。我们引入了一个将人口、背景气候和城市热岛强度联系起来的粗粒度模型，并表明蒸散量和对流效率的城乡差异是变暖的主要决定因素。这些非线性的直接影响是，旨在增加绿化覆盖率和反照率的缓解策略在干旱地区更为有效，而热带城市降温的挑战将需要创新的解决方案。
Urban heat islands (UHIs) exacerbate the risk of heat-related mortality associated with global climate change. The intensity of UHIs varies with population size and mean annual precipitation, but a unifying explanation for this variation is lacking, and there are no geographically targeted guidelines for heat mitigation. Here we analyse summertime differences between urban and rural surface temperatures (Delta T-s) worldwide and find a nonlinear increase in Delta T-s with precipitation that is controlled by water or energy limitations on evapotranspiration and that modulates the scaling of Delta T-s with city size. We introduce a coarse-grained model that links population, background climate, and UHI intensity, and show that urban-rural differences in evapotranspiration and convection efficiency are the main determinants of warming. The direct implication of these nonlinearities is that mitigation strategies aimed at increasing green cover and albedo are more efficient in dry regions, whereas the challenge of cooling tropical cities will require innovative solutions.