The hourly volcanic SO2 column density and a variety of novel volcanic SO2 products from Geostationary Environment Monitoring Spectrometer (GEMS) measurements over Asia

The Geostationary Environment Monitoring Spectrometer (GEMS) onboard the Geostationary Korea Multi-Purpose Satellite-2B (GEO-KOMPSAT-2B) satellite was launched in February 2020 and observes the hourly volcanic SO₂ in geostationary orbit. We For the first time show the hourly changes in volcanic SO₂ distributions emitted and transported from several volcanoes over Asia. The various physical characteristics of volcanic plumes have been investigated based on hourly volcanic SO₂ measurements. We estimated transport direction, path and speed, and altitude of volcanic SO₂ plume emitted from Nishinoshima in Japan, Etna in Italy, Taal volcano in the Philippines and Dukono located in Halmahera, Indonesia. Before the eruption, Taal volcanic SO₂ plumes, which were found to present within PBL, were transported mostly less than 100 km in various azimuth directions. Gradual increase in SO₂ column densities was observed for about two months before a volcanic eruption from Taal. It implies that it might be possible to warn a volcanic eruption in advance which is subject to further investigation. GEMS can be further utilized for an improvement in prediction accuracy of SO₂ plume transport using chemical transport model due to the availability of hourly volcanic SO₂ height information.