Space based observation of volcanic iodine monoxide
Anja Schönhardt1, Andreas Richter1, Nicolas Theys2, and John P. Burrows11Institute of Environmental Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany 2Belgian Institute for Space Aeronomy, Avenue Circulaire 3, B-1180 Brussels, Belgium
Abstract. Volcanic eruptions inject substantial amounts of halogens into the atmosphere. Chlorine and bromine oxides have frequently been observed in volcanic plumes from different instrumental platforms, from ground, aircraft as well as from satellite. The present study is the first observational evidence that iodine oxides are also emitted into the atmosphere during volcanic eruptions. Large column amounts of iodine monoxide, IO, have been observed in satellite measurements following the major eruption of the Kasatochi volcano, Alaska, in 2008. The IO signal is detected in measurements made both by SCIAMACHY on ENVISAT and GOME-2 on MetOp-A. Following the eruption on August 07, 2008, strongly elevated levels of IO slant columns of more than 4 × 1013 molec/cm2 are retrieved along the volcanic plume trajectories for several days. The retrieved IO columns from the different instruments are consistent and the spatial distribution of the IO plume is similar to that of BrO. Details in the spatial distribution, however, differ between IO, BrO and sulphur dioxide, SO2. The columns of IO are approximately one order of magnitude smaller than those of BrO. Using the GOME-2A observations, the total mass of IO in the volcanic plume injected into the atmosphere from the eruption of Kasatochi on August 07, 2008, is determined to be on the order of 10 Mg.
Schönhardt, A., Richter, A., Theys, N., and Burrows, J. P.: Space based observation of volcanic iodine monoxide, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-619, in review, 2016.