PROGRESS IN GEOGRAPHY ›› 2022, Vol. 41 ›› Issue (11): 2061-2072.doi: 10.18306/dlkxjz.2022.11.006

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Population exposure risk to urban extreme heat environment based on ECOSTRESS land surface temperature and mobile phone signaling data: A case study of Xi’an City

ZHAO Xin1(), ZHAO Kaixu1, HUANG Xiaojun1,2,3,*()   

  1. 1. College of Urban and Environmental Sciences, Northwest University, Xi'an 710127, China
    2. Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Xi'an 710127, China
    3. Shaanxi Xi'an Urban Forest Ecosystem Research Station, Xi'an 710127, China
  • Received:2022-04-02 Revised:2022-07-28 Online:2022-11-28 Published:2023-01-28
  • Contact: HUANG Xiaojun E-mail:realzhaox@163.com;huangxj@nwu.edu.cn
  • Supported by:
    National Natural Science Foundation of China(41971178)

Abstract:

The dual effects of global warming and urban heat island have increasingly exacerbated the extreme heat risk, and given severe challenges to the health of urban residents and socioeconomic development. Accurately assessing the population exposure to urban extreme heat environment has become a current research hotspot. In this study, we used the new ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) and mobile phone signaling data to explore the spatiotemporal variation of land surface temperature and population in Xi'an City, developed a population exposure risk assessment model, and revealed the spatiotemporal pattern and dynamic characteristics of the exposure risk on a refined scale. The results show that: 1) The diurnal cycling of land surface temperature in summer showed obvious fluctuation characteristics, especially a large difference between day and night. The average temperature in the daytime was 35.5 ℃ and 21.5 ℃ at night, and land surface temperature exhibited more spatial variations in the daytime. The urban heat island effect of different intensities existed at all times of the day, and it varied from aggregation state to discrete state and then to aggregation state. 2) Nearly three quarters (73.6%) of the population were distributed within the third ring road with a single center structure, and the population was concentrated along the central axis. The population distribution change displayed the characteristics of "centripetal in the daytime and centrifugal at night". 3) The medium risk, high risk, and extremely high risk areas of population exposure were mainly scattered in the central area of the city, and 86.6% of the extremely high risk areas were located within the third ring road, while the negligible risk and low risk areas were mainly concentrated in the periphery. 4) The dominant factors leading to difference of heat exposure risk were grouped into three types including temperature-dominated, population-dominated, and co-dominated, and their proportion to the total urban area were 37.9%, 30.6%, and 31.5%, respectively. This research can provide a scientific reference for the heat exposure risk identification and targeted adaptive strategies.

Key words: ECOSTRESS, land surface temperature, mobile phone signaling, heat exposure risk, Xi'an City