Spatiotemporal Patterns of Human-Perceived Temperature and Its Drivers Over the Rapid Urbanisation Area of China

Recent years have witnessed a significant rise in heat stress, including human-perceived temperature (HPT), which has led to increased incidents of heat stroke and even fatalities, raising considerable concern about the risk to human settlement environments. However, the spatiotemporal pattern of HPT and the potential drivers related to climate and urbanisation remain unclear. This study focuses on the Yangtze River Delta region of China, a typical heat stress-sensitive area, to examine the spatiotemporal dynamics of HPT using six commonly used indices: indoor apparent temperature (AT_in), outdoor shaded apparent temperature (AT_out), discomfort index (DI), effective temperature (ET), heat index (HI) and wet-bulb temperature (WBT). Our analysis indicates a significant upward trend (p < 0.05) during the summer months from 1990 to 2019. AT_out and WBT represent the most and least warming indices, respectively. Trends in HPT indices show significant regional variations. Over half of the cities analysed (56%) demonstrate positive urban–rural temperature differentials across all indices, with the most pronounced warming occurring in humid regions. The increase in anthropogenic heat emissions primarily drives HPT in the relatively arid regions in the northern and eastern areas. In contrast, decreasing vegetation cover contributes to changes in the southwestern, more humid area. Our findings can provide theoretical support for improving urban thermal environment management and developing mitigation strategies for human health.