Detection Capability of Eruption Clouds and Observations of Eruption Sequences by GMS Images

Abstract

Images of Geostationary Meteorological Satellite (GMS) since 1977 through 1984 are inspected to elucidate its detection capability of eruption clouds in the field of view of GMS. During this period above, eruption clouds by 26 volcanic eruptions of 196 events in total are detected and the detection capability is about 13%. The lowermost of altitude and dimension of detected eruption clouds are around 5 km and 30 km, respectively.
It is difficult to find out small-scale and ascending eruption clouds at the initial stage of eruptions, but the sequences such as time variations of driftdirections and coverage areas of the clouds, and decay of eruptive activities are fairly well observed by analyses of the whole shapes of eruption clouds, altitudes and isothermal squares of the upper surface of eruption clouds. The thermal energy release during eruption periods is estimated on the basis of thermal energy release rate by Briggs's formula(1969) and the supposed duration-times of eruptions, and the results are approximately proportional to intensities of respective eruptive activities.
Further increase of detection capability and more precise observations of volcanic eruption-sequences will be realized by increase of image-taking frequency and application of higher resolution sensors.