Review of Cooling Effects from Roof Mitigation Strategies Against Urban Heat Island Effects

The rapid increase in global human activities and urban surface modifications has exacerbated the urban heat island effect, prompting growing scholarly efforts to adopt various measures for mitigating heat islands worldwide. This paper reviews existing literature on rooftop mitigation of UHI, summarizes specific existing rooftop mitigation measures, and examines the comparative effectiveness of various rooftop mitigation strategies in reducing urban heat islands. Findings indicate that cool roofs are the most effective rooftop measure for mitigating UHI, followed by green roofs and photovoltaic roofs. Simultaneously, the cooling effectiveness of rooftop mitigation strategies is influenced by their inherent characteristics (reflectivity, coverage, orientation, etc.), geographical and climatic features (latitude, humidity levels, temperature extremes, diurnal temperature variation, etc.), and urban morphology (building density, height, shape index, etc.). The research status summarized herein provides valuable insights for policy formulation and guides future studies, thereby promoting more innovative designs for sustainable urban roofs to mitigate UHI.