Opportunistic observations of Mount Erebus volcanic plume HCl, HF and SO2 by high resolution solar occultation mid infra-red spectroscopy

Abstract

Opportunistic large bandwidth, high resolution, high signal to noise ratio mid-infrared solar occultation spectral measurements of the Mount Erebus (Ross Island, Antarctica) volcanic plume have been analysed to retrieve HCl, HF and SO2 plume volume mixing ratios. Such measurements are sparse, comprising of only eight observations spanning 26 years. The calculated mean mass ratios of HF/HCl (2.11+/-0.38), HCl/SO2 (0.56+/-0.08) and HF/SO2 (0.35+/-0.06) are comparable to other measurements. The mean mass ratios are consistent over time indicating long term stability of Erebus volcanic processes and composition.