Interactions between urban heat islands and heat waves
Interactions between urban heat islands and heat waves
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DOI：
10.1088/1748-9326/aa9f73
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发表时间：
2018-02
影响因子：
6.7
通讯作者：
Lei Zhao;M. Oppenheimer;Qing Zhu;J. Baldwin;K. Ebi;E. Bou‐Zeid;K. Guan;X. Liu
中科院分区：
文献类型：
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作者：
Lei Zhao;M. Oppenheimer;Qing Zhu;J. Baldwin;K. Ebi;E. Bou‐Zeid;K. Guan;X. Liu
热浪（HWs）是对人类社会最具破坏性的极端气候之一。气候模型一致预测，HW的频率，严重性和持续时间将显着增加，在本世纪。对于城市居民来说，城市热岛效应进一步加剧了HWs引起的热应激。在这里，我们使用的气候模式，调查在美国的50个城市的热岛和HWS之间的相互作用，在当前的气候和未来的变暖情景。我们检查UHI2m（定义为城乡差异在2m高度的空气温度）和UHIs（定义为城乡差异在辐射表面温度）。我们的研究结果表明，显着的敏感性之间的相互作用，城市热岛和HWs当地的背景气候和变暖的情况。白天和夜间的灵敏度也有所不同。在白天，在温带气候区的城市表现出显着的协同效应之间的UHI和HWs在当前的气候，与平均0.4 K高UHI2m或2.8 K高UHIs在HWs比在正常的日子。然而，这些协同效应在未来更温暖的气候中会减弱。与此相反，白天协同效应的城市在干旱地区是微不足道的，在当前的气候，但出现在未来的气候。在夜间，协同效应在当前气候下的气候区域之间相似，在未来气候情景中更强。我们使用生物物理因子分解方法解开背后的机制，解释的时空格局的相互作用之间的相互作用的城市热岛和HWS。结果表明，城市与农村蒸发量增加的差异和HWs期间人为热排放（空调能源使用）的增强是白天协同效应的关键因素。城市和农村土地之间的水资源对比在确定蒸发的贡献方面起着重要作用。在夜间，增强释放的存储和人为的热量在HWs的协同效应的主要贡献者。
Heat waves (HWs) are among the most damaging climate extremes to human society. Climate models consistently project that HW frequency, severity, and duration will increase markedly over this century. For urban residents, the urban heat island (UHI) effect further exacerbates the heat stress resulting from HWs. Here we use a climate model to investigate the interactions between the UHI and HWs in 50 cities in the United States under current climate and future warming scenarios. We examine UHI2m (defined as urban-rural difference in 2m-height air temperature) and UHIs (defined as urban-rural difference in radiative surface temperature). Our results show significant sensitivity of the interaction between UHI and HWs to local background climate and warming scenarios. Sensitivity also differs between daytime and nighttime. During daytime, cities in the temperate climate region show significant synergistic effects between UHI and HWs in current climate, with an average of 0.4 K higher UHI2m or 2.8 K higher UHIs during HWs than during normal days. These synergistic effects, however, diminish in future warmer climates. In contrast, the daytime synergistic effects for cities in dry regions are insignificant in the current climate, but emerge in future climates. At night, the synergistic effects are similar across climate regions in the current climate, and are stronger in future climate scenarios. We use a biophysical factorization method to disentangle the mechanisms behind the interactions between UHI and HWs that explain the spatial-temporal patterns of the interactions. Results show that the difference in the increase of urban versus rural evaporation and enhanced anthropogenic heat emissions (air conditioning energy use) during HWs are key contributors to the synergistic effects during daytime. The contrast in water availability between urban and rural land plays an important role in determining the contribution of evaporation. At night, the enhanced release of stored and anthropogenic heat during HWs are the primary contributors to the synergistic effects.