Effects of urbanization and topography on thermal comfort during a heat wave event: A case study of Fuzhou, China
Zefeng Zheng, Xinlu Lin, Li Chen, Chao Yan, Ting Sun
Abstract
Urbanization intensifies urban heat and compromises thermal comfort. However, few studies have examined the interactions of Urban Heat Island (UHI) between neighboring cities and the impacts of expanding satellite towns on central urban areas (CUA). We conducted a series of WRF/BEP-BEM simulations during a summer heat wave in Fuzhou, China, to understand how extensive urbanization and complex topography affect thermal comfort. Control runs reveal an intense UHI centered on Fuzhou’s CUA. Comparisons with scenarios where urban land use and terrain are altered demonstrate that urbanization degrades thermal comfort citywide by elevating heat stress while valley-basin topography worsens midday heat but alleviates nighttime humidity. The urban heat island circulation above the CUA suppresses the valley wind circulation and prevents the sea breeze front from advancing inland in the afternoon. Notably, CUA urbanization enhances sea breezes in a satellite town, inducing afternoon “cool islands”. Interactions between CUA and satellite towns appear minimized, with urbanization impacts confined locally. Future expansion according to the “Fuzhou 2035” Master Plan shows negligible effects on thermal comfort in CUA. Our findings enhance understanding of intra-urban UHI dynamics in complex terrains. The outcomes directly inform urban planning and climate adaptation strategies to promote Fuzhou’s livability and resilience.