A mechanistic assessment of urban heat island intensities and drivers across climates

The urban heat island effect (UHI) has been widely observed globally, causing climate, health, and energy impacts in cities. UHI intensities have found to largely depend on background climate the properties of fabric. Yet, a complete mechanistic understanding how UHIs develop at global scale is still missing. Using an ecohydrological land-surface model (urban Tethys-Chloris) combination with multi-source remote sensing data, we performed simulations for 49 large clusters across Northern Hemisphere 2009–2019 analysed surface canopy air (SUHI CUHI, respectively) during day night. Biophysical drivers triggering development SUHIs CUHIs similar dependencies but different magnitudes. In humid regions daytime can be explained by urban-rural difference evapotranspiration, whereas convection conduction are important arid areas. Plant irrigation promote evapotranspiration only semi-arid climates. During night, from fabric environment creates mostly warm regions. Overall, this study presents quantification worldwide proposes viable solutions sustainable climate-sensitive mitigation strategies.