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| Titel |
Systematic investigation of bromine monoxide in volcanic plumes from space by using the GOME-2 instrument |
| VerfasserIn |
C. Hörmann, H. Sihler, N. Bobrowski, U. Platt, T. Wagner |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250068286
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| Zusammenfassung |
| Bromine monoxide (BrO) plays a key role as a catalyst in the depletion of both tropospheric
and stratospheric ozone (O3), e.g. during springtime in polar regions. In addition to sources
like salt lakes or the surface of sea ice in polar regions, it turned out that volcanic emissions
are a further natural source of BrO. The injection of bromine compounds from persistent
degassing volcanoes as well as during major eruptions, might therefore have an important
impact on atmospheric chemistry. Since the first observation of BrO in the volcanic plume of
Soufrière Hills in 2002 by ground-based Multi-Axis Differential Optical Absorption
Spectroscopy (MAX-DOAS) measurements, similar observations have been made at several
volcanoes worldwide.
While a first investigation of data from the GOME and SCIAMACHY satellite instruments
failed to detect volcanic BrO also from space for selected volcanic events, large amounts of
BrO were detected for the first time in the plume of the Kasatochi eruption in August 2008 by
GOME-2. This showed the capability of GOME-2 to monitor such events and that satellite
instruments offer in principle the unique opportunity to investigate the behavior of BrO inside
volcanic plumes for large scales, what is usually not possible with ground-based
measurements.
In order to detect further events of volcanic unrest, where BrO might be present in
the vicinity of the plume, we systematically investigated the whole dataset of the
GOME-2 satellite instrument from the beginning of the measurements in January 2007
until June 2011. Almost 800 volcanic plumes were automatically extracted from
the data by using sulfur dioxide (SO2) as a proxy and the slant column densities
(SCDs) for BrO were additionally retrieved. While the majority of the captured
volcanic plumes showed no signs for enhanced BrO, several other plumes were found
with clear evidence for volcanic BrO next to SO2, even for minor eruptions. In
the latter case, the resulting SCDs for both species were analyzed for a possible
correlation and the BrO/SO2 ratios are discussed. The results show, that a close
correlation between SO2 and BrO only occurs for some of the observed eruptions
or only for certain parts of the examined volcanic plumes. For some other cases,
only a rough spatial correlation can be found. We discuss possible explanations
for the occurrence of different spatial SO2 and BrO distributions in aged volcanic
plumes. |
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