Spatiotemporal Evolution of Nighttime Light During the COVID-19 Pandemic in Major Cities of South Korea

The government of South Korea implemented social distancing regulations to tackle the surging number of confirmed cases of coronavirus disease 2019 (COVID-19) to reduce transmission. Implementation of social distancing has affected human behavior in activities which can be observed through the change in nighttime light (NTL). Human activities at night can describe a situation during social restrictions and represent their response to the situation. Remote sensing technique supported by satellite capabilities provides NTL data in observing the earth’s surface at night from space. In this study, visible NTL data were acquired from the Suomi satellite. We collected 887 Suomi data from 1 January 2020 until 27 June 2022 to analyze the time series of NTL radiance change over six major cities in South Korea to investigate the relationship with social distancing regulation. A higher level of regulation restricting human activities was integrated with the closure of various facilities. The findings showed that the application of various social distancing levels impacted the temporal and spatial disparities in NTL radiance. In addition, the results of this study indicate that it is difficult to manage infectious diseases with only the government's control policy when the number of infections increases dramatically. Therefore, this study can be helpful for the government in reviewing and improving regulations in efforts to control and prevent COVID-19 outbreaks in the future.