Impact Assessment of PSBB on Variations of NO2, CO, and Chlorophyll-a Concentration in Java Island during the COVID-19 Pandemic based on Multi-satellite Imagery Data

Abstract

The enactment of the PSBB (Large-scale Social Restriction) on April to May 2020 due to COVID-19 pandemic, has reduced residents’ activities, especially in Java Island, the most populous area in Indonesia with high anthropological activities. This policy may affect the conditions of atmospheric and water environment around the island of Java. NO<sub>2</sub> and CO concentrations in atmosphere along with chlorophyll-a concentrationin the ocean are environmental indicators that can be observed through satellite imagery. Satellite data TROPOMI and CMEMS were used to investigate the variation of those concentrations in the atmosphere and ocean during PSBB. Oceanographic and atmospheric daily data of each parameter over the Java Island region were retrieved and merged into gridded data with 1 km spatial resolution to be compared. Variations of chlorophyll-a concentration within the same month over the previous years were also taken into account. NO<sub>2</sub>, CO, and chlorophyll-a concentration were fluctuating during the PSBB period, but tended to decrease in the early phase of PSBB.The higher concentration of chlorophyll-a concentrated in the northern coastal areas of Java Island. In Jakarta and Surabaya, chlorophyll-a concentrations value during April-May 2020 were decreased by 48% and 27% compared to the previous three years’ averages. Human activities were thought to be the main factor influencing variations in the concentration of NO<sub>2</sub>, CO, and chlorophyll-a during PSBB enactment