Detection and Tracking of Aerosols From the 2008 Kasatochi Eruption in the Lower Stratosphere With OSIRIS Limb Scattered Sunlight Spectra

The eruption of the Kasatochi Volcano in the central Aleutian Arc on August 7, 2008 produced plumes of gas and aerosol that reached lower stratospheric altitudes. These plumes are detected by the Canadian Optical Spectrograph and InfraRed Imaging System (OSIRIS) satellite instrument. OSIRIS is an optical spectrograph that collects vertical profiles of the limb radiance spectra at UV, visible and near-infrared wavelengths, with approximately 2 km vertical resolution. At lower stratospheric altitudes, the aerosol in these volcanic plumes produces a significant enhancement of the near infrared limb radiance, even for relatively low vertical optical depths. Given the good horizontal sampling of the limb scatter technique in the summer hemisphere, these measurements allow for the tracking of the vertical and horizontal extent of the Kasatochi plume in the lower stratosphere.