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| Titel |
SO2 camera measurements at Lastarria volcano and Lascar volcano in Chile |
| VerfasserIn |
Peter Lübcke, Nicole Bobrowski, Florian Dinger, Angelika Klein, Jonas Kuhn, Ulrich Platt |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250102193
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| Publikation (Nr.) |
 EGU/EGU2015-1799.pdf |
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| Zusammenfassung |
| The SO2 camera is a remote-sensing technique that measures volcanic SO2 emissions via the
strong SO2 absorption structures in the UV using scattered solar radiation as a light source.
The 2D-imagery (usually recorded with a frame rate of up to 1 Hz) allows new insights into
degassing processes of volcanoes. Besides the large advantage of high frequency sampling
the spatial resolution allows to investigate SO2 emissions from individual fumaroles and not
only the total SO2 emission flux of a volcano, which is often dominated by the volcanic
plume. Here we present SO2 camera measurements that were made during the CCVG
workshop in Chile in November 2014. Measurements were performed at Lastarria volcano, a
5700 m high stratovolcano and Lascar volcano, a 5600 m high stratovolcano both
in northern Chile on 21 – 22 November, 2014 and on 26 – 27 November, 2014,
respectively. At both volcanoes measurements were conducted from a distance of
roughly 6-7 km under close to ideal conditions (low solar zenith angle, a very dry and
cloudless atmosphere and an only slightly condensed plume). However, determination
of absolute SO2 emission rates proves challenging as part of the volcanic plume
hovered close to the ground. The volcanic plume therefore is in front of the mountain
in our camera images. An SO2 camera system consisting of a UV sensitive CCD
and two UV band-pass filters (centered at 315 nm and 330 nm) was used. The two
band-pass filters are installed in a rotating wheel and images are taken with both filter
sequentially. The instrument used a CCD with 1024 x 1024 pixels and an imaging area of
13.3 mm x 13.3 mm. In combination with the focal length of 32 mm this results
in a field-of-view of 25° x 25°. The calibration of the instrument was performed
with help of a DOAS instrument that is co-aligned with the SO2 camera. We will
present images and SO2 emission rates from both volcanoes. At Lastarria gases are
emitted from three different fumarole fields and we will attempt to investigate the
degassing behavior of the individual fumaroles. Lascar volcano only had a very
weak plume originating from the active central crater with maximum SO2 column
densities of only up to 5 x 1017[molecules/cm2] during our measurements. These
low SO2 column densities in combination with the almost ideal measurements
conditions will be used to assess the detection limit of our current SO2 camera
system. |
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