A scanning imaging spectrograph system was used in this study to retrieve readings of the 2-D distribution of SO2 and BrO around the crater of the Sakurajima volcano in Japan. The measurement was carried out during the daytime on November 2, 2005. Measurements were made at the surface of the site, located 5 km from the Sakurajima crater. One hundred horizontal scans were performed. Each column scanned by the system consists of 64 vertical pixels in order to retrieve the spatial distributions of BrO and SO2 in the plume in terms of slant column densities (SCDs). Measured spectra were analyzed to identify and quantify SO2 and BrO in the volcanic plume utilizing the plume's specific absorption features in the ultra violet region. Two-dimensional BrO and SO2 distributions in SCD were retrieved horizontally covering the upwind, crater and downwind areas, and vertically, including the plume in the center of the scanned image. Both horizontal and vertical dispersions of SO2 SCD from the crater were successfully measured to be from 1017 to 4.5 × 1018 molecules cm-2. However, BrO was measured below 1015 molecules cm-2, which is considered its background level.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics