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| Titel |
Spatially distributed OClO-profiles in the volcanic plume of Mt. Etna, Sicily |
| VerfasserIn |
Jonas Gliss, Nicole Bobrowski, Marco Huwe, Constantin Mayer, Henning Finkenzeller, Leif Vogel, Ulrich Platt |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250081790
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| Zusammenfassung |
| The study of the chemical composition of volcanic plumes is important both for the
understanding of volcanic processes and the influence of volcanic activity on the atmosphere.
Reactive halogen-species such as BrO, ClO, OClO are abundant in volcanic plumes and
can have several effects on the atmosphere (e.g. local ozone depletion by catalytic
halogen-reactions).
Multi Axis Differential Absorption Spectroscopy (MAX-DOAS) is an established method
to determine reactive components in volcanic plumes by analysing scattered sunlight which
has traversed the plume.
We present MAX-DOAS measurements that were performed at Mt. Etna, Sicily in
September 2012 with a newly developed MAX-DOAS-instrument. Both, vertical and
horizontal plume-scans as well as point measurements were done in distances of several
hundred meter up to 30 km from the emission source. For the first time it was possible to
measure spatial distributions of the halogen compound chlorine dioxide (OClO) in a volcanic
plume. OClO column-densities (SCDs) up to 2 -
1014 molecules/cm2 were measured in an
area of about 2 km around the emission source. OClO/SO2-ratios between 1 -
10-5 and
4 -
10-4 were determined. Along with the evaluation of OClO the species bromine monoxide
(BrO) as well as sulphur-dioxide (SO2) were evaluated for each data set. BrO-SCDs up to
1.1 -
1015 molecules/cm2 and BrO/SO2-ratios between 2 -
10-5 and 5 -
10-4 were
determined.
Assuming a plume width of less than 1 km the measured values correspond to OClO and
BrO concentrations of several hundred ppt in the plume.
From the measured OClO- and BrO-SCDs and by assuming steady-state between the
production of OClO from BrO and ClO and its photolytic destruction, ClO concentrations
between 70 ppt and 1.0 ppb were derived.
We will discuss these results and their importance to improve our knowledge about
chlorine-chemistry in volcanic plumes. |
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