Articles | Volume 17, issue 7
https://doi.org/10.5194/acp-17-4857-2017
https://doi.org/10.5194/acp-17-4857-2017
Research article
 | 
13 Apr 2017
Research article |  | 13 Apr 2017

Space-based observation of volcanic iodine monoxide

Anja Schönhardt, Andreas Richter, Nicolas Theys, and John P. Burrows

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 such as from ground, aircraft and satellites. 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, are 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 (Scanning Imaging Absorption Spectrometer for Atmospheric CHartographY) on ENVISAT (Environmental Satellite) and GOME-2 (Global Ozone Monitoring Experiment-2) on MetOp-A (Meteorological Operational Satellite A). Following the eruption on 7 August 2008, strongly elevated levels of IO slant columns of more than 4 × 1013 molec cm−2 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 bromine monoxide, BrO. Details in the spatial distribution, however, differ between IO, BrO and sulfur dioxide, SO2. The column amounts of IO are approximately 1 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 7 August 2008, is determined to be on the order of 10 Mg.

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Short summary
Iodine monoxide, IO, is observed in satellite measurements following the eruption of the Kasatochi volcano, Alaska, in August 2008. Large IO columns are detected by SCIAMACHY on ENVISAT and by GOME-2 on MetOp-A for several days. IO amounts are approximately 1 order of magnitude smaller than those of BrO. Details in the spatial distributions differ between IO, BrO and sulfur dioxide, SO2. The total mass of IO in the volcanic plume is determined to be on the order of 10 Mg.
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