Space-based observation of volcanic iodine monoxide

Abstract

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.

Advances in Bromine Speciation in Volcanic Plumes

“…Bobrowski et al (2017) reported that the total iodine already comprises 8-18% non-hydrogen iodide measured at the crater rim of the pit crater at Nyamuragira. A major eruption of Kasatochi, Aleutian Islands 2008 enabled rare detection of IO in the volcanic plume in the stratosphere by satellite (Schönhardt et al, 2017). We highlight that the ozone depletion potential of iodine may have significant ozonedepletion impacts even as a trace emission.…”

Periodicity in Volcanic Gas Plumes: A Review and Analysis

“…Volcanic gas emissions are predominantly composed of water vapor (H 2 O), carbon dioxide (CO 2 ), and sulfur dioxide (SO 2 , or in reduced form, hydrogen sulfide, H 2 S), with SO 2 being the easiest to resolve against background atmospheric concentrations and therefore, generally the target gas used for emissions measurements [6]. Present generally in trace quantities are halogen compounds such as chlorine, fluorine, bromine, and iodine, the latter of which is highly reactive in the atmosphere forming gaseous species such as bromine monoxide (BrO), and iodine monoxide (IO) [7][8][9].…”

First high resolution BrO column retrievals from TROPOMI

“…SCIAMACHY which followed GOME not only measured BrO columns but also vertical profiles of BrO in the stratosphere from limb measurements (Rozanov et al, 2005;Kuhl et al, 2008). The higher spatial resolution data of GOME-2 and OMI have been successfully used to monitor daily global distribution as well as BrO emissions from various source regions such as volcanoes (Theys et al, 2009;Hörmann et al, 2013;Schönhardt et al, 2017), salt lakes (Hörmann et al, 2016) and polar sea ice regions (Begoin et al, 2010;Salawitch et al, 2010;Sihler et al, 2012;Blechschmidt et al, 2016;Suleiman et al, 2018). However, OMI's coverage has been reduced since 2008 due to the so-called "row anomaly", which is the result of a physical obstruction of the instrument, and currently, the anomaly effect extends over about 50% of the sensor's viewing positions (Torres et al, 2018).…”