Satellite-based investigation of immediate impact of forest fires on the spatial distribution of aerosol loading over India

This study investigates the impact of forest fires on the spatial distribution of aerosols over the Indian region during the initial phase of the national lockdown due to the COVID-19 pandemic in April and May 2020. Given the significant reduction in anthropogenic emissions during this period, it provides a suitable opportunity to isolate the effect of fire activity on aerosol loading. The present study conducts a spatial correlation analysis to examine the spatial extent of pollution plumes produced by forest fires over India. Statistically significant correlation analysis (p<0.05) using Satellite-derived fire and aerosol observations indicates that burning in central India modulates the aerosol optical depth (AOD) over the Bay of Bengal on the same day. A lag analysis shows that the impacts of fire pollution emitted from Central India persist over Bay of Bengal up to 4 days after the events, which can affect the air quality and thermodynamics of the marine atmosphere. It is also observed that the fire-AOD correlation is more pronounced over the transported regions than at the source region indicating the influential role of transport in shaping unexpected aerosol patterns over India. Present study provides the spatial footprint and temporal persistence of fire-pollution over India using collocated satellite measurements of fire and aerosols, based on physical linkage and empirical evidence.