Time-resolved observation of volcanic ash using COMS/MI: A case study from the 2011 Shinmoedake eruption

Between January 26 and 27, 2011, Shinmoedake volcano, located in the Krishima complex in Kyushu, Japan, produced a number of explosive eruptions with ash clouds reaching up to 8.5 km above sea level. Volcanic ash (VA) plumes from those eruptions affected the population near the volcano and posed a significant threat to aviation. Since its launch on June 27, 2010, the Meteorological Imager (MI) onboard Korea's first geostationary meteorological satellite, the Communication, Ocean, and Meteorological Satellite (COMS), has provided time-resolved images (less than 27-minute intervals for the full disk) at 1 km spatial resolution for the visible (VIS) channel and 4 km spatial resolution for the four infrared (IR) channels. In this study, MI operational data with one broadband VIS channel (centered at 0.68 μm) and three IR channels (centered at 3.7, 10.8, and 12.0 μm) for eruption events occurring at Shinmoedake were analyzed using the formerly developed hybrid VA detection and retrieval algorithm. We analyzed time-resolved VA plumes produced during three subplinian eruptions and found that spatio-temporal distributions of VA pixels determined by this analysis agreed with the source-receptor regions in meteorological trajectory modeling as well as with the operational products from the Global Ozone Monitoring Experiment-2 (GOME-2), Scanning Imaging Absorption spectrometer for Atmospheric Cartography (SCIAMACHY), and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). For the three subplinian eruptions, VA retrieval results revealed that the maximum total ash mass loadings were 115.1, 1309.7, and 51.3 t, and the maximum height reached by the ash clouds were 5.6 ± 0.7, 10.2 ± 2.4, and 5.6 ± 0.8 km, respectively. These values imply that the second eruption emitted the largest amount of VA into the atmosphere. Overall, this is the first study that has been conducted to detect VA using the COMS/MI observations, which have been determined to provide reliable estimates of VA.