Sulfur dioxide flux estimation from volcanoes using Advanced Spaceborne Thermal Emission and Reflection Radiometer—a case study of Miyakejima volcano, Japan

A method is described for estimating the two-dimensional spatial distribution of volcanic SO2 using thermal infrared image data acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The author proposes a new method to estimate wind velocity and plume height using an along-track stereoscopic pair image. Volcanic SO2 flux can be estimated from the spatial distribution of SO2 and wind velocity. Since ASTER has both the Thermal Infrared Radiometer (TIR) and stereoscopic viewing function in the along-track direction, the volcanic SO2 flux can be estimated from the ASTER data alone. These methods are applied to the Miyakejima volcano, Japan. The SO2 flux derived from ASTER is around 5×104 ton/day (580 kg s−1), which is slightly larger than the value derived from COSPEC. The plume height estimation error may cause this disagreement because the SO2 estimation procedure is very sensitive to the plume height.