Characterizing individual mobility perturbations in cities during extreme weather events

Abstract

Understanding the patterns of urban human mobility has played an important role in multiple disciplines such as urban planning, transportation engineering and social sciences. Due to its rich connotations related to urban regions, the extreme weather events (EWEs)-induced perturbation of human mobility has been studied to capture the multifaceted influences of EWEs on cities. While this issue has drawn increasing attention, there is still limited understanding of EWE-induced mobility perturbation at the individual level. To address this need, a new analytical framework for individual mobility perturbation is proposed in this study. The framework assesses individual mobility perturbation during EWEs by taking various facets of spatial and temporal features into consideration, and examines the individual variation of such perturbation. To demonstrate the efficiency of the proposed framework, two consecutive typhoon events that influenced the city of Guangzhou, China in summer 2017 were examined as a case study. It was found that individuals in the city experienced notable decreases in the number of visited locations, visitation frequency and movement range, increases in waiting time, and changes in movement status pattern under these two EWEs. Moreover, mobility perturbation showed significant variation among individuals, and such variation was linked to individuals' demographic attributes, home location and travel preference. Meanwhile, four types of responses to EWE impacts were extracted from the population. The findings in this study contribute to a manifold understanding of EWE-induced individual mobility perturbations, and have potential to be transformed into actionable measures in urban EWE risk reduction and management practices.