Depicting human mobility across functional zones to elevate urban heat exposure management-A case study of Shenzhen, China

Wang, Ting

CITIES

2026

171

Fang, Z

Urban high temperatures are increasingly severe, significantly impacting public health and quality of life. Spatial interactions amplify individuals' exposure to high temperatures, thereby heightening the risk of heat-related hazards. Mobile populations, in contrast to static indoor populations, often demand greater attention from urban managers. However, widespread cooling interventions can lead to increased costs and resource inefficiencies. This study addresses these challenges in three key steps. First, we utilize mobile phone data to extract spatial interaction behaviors and mobility intensities of populations at various times. Second, we develop a novel heat exposure risk assessment framework by integrating the concept of crowd activity intensity into the existing heat exposure model. Lastly, we apply this framework to Shenzhen's Futian District to generate heat exposure risk maps for different times of the day. The study reveals the following key findings: (1) Significant variations in land surface temperatures, particularly in urban core areas where high building density and concentrated human activities exacerbate heat island effects. (2) The spatial gravity model quantifies crowd activity intensity, illustrating population movement and activity distribution across Futian District, which is critical for understanding heat exposure risks. The intensity of human activity demonstrates a trend of shifting from north to south, with a primary concentration in the central areas. (3) The heat exposure risk assessment model, based on functional zone delineation, highlights significant differences in risk levels among zones during high-temperature periods. For instance, Zones B and C (Xiangmi Lake New Financial Center and Futian Central District) exhibit higher risks between 12:00 PM and 5:00 PM, whereas Zone A (Meilin Living Circle) shows elevated risks during peak residential activity times, from 6:00 AM to 9:00 AM. These variations are closely related to the functional orientation of each zone. The findings of this study provide valuable insights for decision-makers, enabling more effective and efficient heat risk management through time-segmented strategies tailored to different functional zones and population dynamics.