Correlation analysis between the community mobility and nighttime lights in the city of Istanbul, Turkey

The COVID-19, which emerged in Wuhan, China, in 2019, has significantly affected people’s Daily lives, business environment, surrounding environment, and countries' economic and social conditions. This study aims to measure the correlation between community mobility changes in six different areas and nighttime lights in the city of Istanbul, Turkey. Nighttime light data used in the study was obtained from VIIRS Nighttime Day/Night Band Composites Version 1 using remote sensing methods via Google Earth Engine platform. Then the correlation between Nighttime light values and community mobility values was investigated. It has been observed that the correlation values have changed dramatically over the years. The most significant correlation values were observed for the year 2020. This is because 2020 is the year when the pandemic is most effective, and restrictions are at the highest level in Turkey. The increase in freedom in the following years caused a decrease in the correlation. When the correlation results covering the period of February 2020 - to January 2022 were examined, it was observed that there was no significant relationship between nighttime light values and Google Community Mobility Reports’ variables. Considering the correlation results for 2020, it was observed that there was a high negative correlation between nighttime light data and mobility trends for grocery and pharmacy, and mobility trends for places of work. In addition, there was a moderate negative correlation between nighttime light data and mobility trends for retail and recreation, and a moderate positive correlation between nighttime light and mobility trends for places of residence. When the correlation values of 2021 and the correlation values of the period 2021-2022 were examined, no significant relationship was observed.