Yuan Yuan, Li Chengwei, Geng Xiaolei, Yu Zhaowu, Fan Zhengqiu, Wang Xiangrong
Department of Environmental Science & Engineering, Fudan University, Shanghai 200438, China.
Department of Environmental Science & Engineering, Fudan University, Shanghai 200438, China.
Environ Int. 2022 Dec;170:107574. doi: 10.1016/j.envint.2022.107574. Epub 2022 Oct 8.
The inconstant climate change and rapid urbanization substantially disturb the global thermal balance and induce severe urban heat island (UHI) effect, adversely impacting human development and health. Existing literature has revealed the UHI characteristics and driving factors at an urban scale, but interactions between the main factors of a global grid scale assessment on the context of climate zones remain unclear. Therefore, based on the multidimensional climatic and socio-economic statistical datasets, the multi-time scale of surface urban heat island intensity (SUHI) characteristics was investigated in this study to analyze how natural-anthropogenic drivers affect the variance of SUHI and vary in their importance for the changes of other interaction factors. The results show that the mean value of SUHI in summer is higher than in winter, and in daytime is higher than in nighttime on a seasonal and daily scale. SUHIs in different global climate zones have significant differences. When analyzing drivers' contributions and interactions with LightGBM model and SHAP algorithm, we know that monthly precipitation (PREC), the estimated population (POP) and surface pressure (PRES) are the three major drivers of daytime SUHI. The nighttime SUHI is mainly PREC, POP and anthropogenic heat emission (AHE), the influence rules of the natural driversare mostly opposite to that of daytime. This study highlights the fundamental role of background climate for designing strategies. Irrigation or artificial rainfall will be effective to mitigate SUHI in low rainfall areas, while it is more effective to reduce AHE in high rainfall areas. In where greening can be difficult in the most developed cities, reducing AHE, increasing per capita GDP and controlling the population scale may also contribute to alleviating the SUHI. This study provides ideas for developing responsive urban heat island mitigation policies in a more realistic setting.
气候变化无常和快速城市化极大地扰乱了全球热平衡，引发了严重的城市热岛效应，对人类发展和健康产生了不利影响。现有文献揭示了城市尺度上的城市热岛特征和驱动因素，但在气候区背景下全球网格尺度评估的主要因素之间的相互作用仍不明确。因此，基于多维气候和社会经济统计数据集，本研究调查了地表城市热岛强度（SUHI）特征的多时间尺度，以分析自然 - 人为驱动因素如何影响SUHI的变化以及它们对其他相互作用因素变化的重要性如何变化。结果表明，在季节和日尺度上，夏季SUHI的平均值高于冬季，白天高于夜间。不同全球气候区的SUHI存在显著差异。当使用LightGBM模型和SHAP算法分析驱动因素的贡献和相互作用时，我们发现月降水量（PREC）、估计人口（POP）和地表气压（PRES）是白天SUHI的三个主要驱动因素。夜间SUHI主要是PREC、POP和人为热排放（AHE），自然驱动因素的影响规律大多与白天相反。本研究强调了背景气候在设计策略中的基础作用。在低降雨地区，灌溉或人工降雨将有效减轻SUHI，而在高降雨地区减少AHE更有效。在最发达城市绿化可能困难的地方，减少AHE、提高人均GDP和控制人口规模也可能有助于缓解SUHI。本研究为在更现实的背景下制定针对性的城市热岛缓解政策提供了思路。
