Diurnal variations of anthropogenic sulfur dioxide over Asia observed from GEMS

Abstract

Sulfur dioxide emissions (SO2) from coal-fired power plants are known as a major contributor to air pollution. SO2 emitted into the atmosphere forms sulfate aerosols, leading to acid rain and causing damage to forests. Moreover, exposure to SO2 in humans can cause eye irritation and affect respiratory health. This study presents the column density variations of anthropogenic SO2 over Asia using the Geostationary Environment Monitoring Spectrometer (GEMS) onboard the Geostationary Korea Multi-Purpose Satellite-2B (GEO-KOMPSAT-2B). We investigated the diurnal variations of SO2 emissions from anthropogenic sources, such as coal-fired power plants in India. Retrieved SO2 columns from GEMS were compared with low-orbit satellites In the GEMS observation area, there was a tendency of low sensitivity in SO2 retrieval due to scattering by air molecules in the high geometry region, particularly at a high viewing zenith angle (VZA), resulting in high uncertainty in SO2 retrieval. We discuss these tendencies in detail through an investigation of SO2 retrieval sensitivity based on concentration and geometry.