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| Titel |
Imaging volcanic SO2 plumes with UV cameras |
| VerfasserIn |
C. Kern, C. A. Werner, M. P. Doukas, T. Elias, P. J. Kelly, A. J. Sutton |
| 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 |
250070094
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| Zusammenfassung |
| Ultraviolet (UV) cameras allow the two-dimensional imaging of SO2 distributions at
temporal resolutions on the order of 1Hz. Optical bandpass filters that selectively transmit
only UV wavelengths at which SO2 absorption occurs (or, for reference, wavelengths at
which absorption is negligible) are positioned in the camera’s optical system, thus providing
selective sensitivity to SO2. As SO2 is one of the main volatile species associated
with high-temperature volcanic degassing, UV camera systems are increasingly
being applied to volcanic environments for monitoring and research purposes. The
relatively high frame rate of these cameras allows the retrieval of SO2 emission fluxes
on time scales comparable to those on which other geophysical parameters (e.g.
seismicity, deformation) are recorded, thus making an integrated evaluation possible.
While impressive imagery of a volcanic plume’s extent is readily obtained, lingering
challenges include obtaining an accurate SO2 column density calibration, correcting for
complex radiative transfer in and around volcanic plumes (which are often visually
opaque), and deriving accurate flux measurements truly representative of volcanic
activity and not overly biased by atmospheric turbulence and other secondary effects.
Here, these issues are addressed, innovative solutions are presented, and example
measurements from Kilauea Volcano (Hawaii) are shown. Although time-averaged SO2
emission rates were typically below 10 kg/s (~900 t/d) during measurements in
September and October 2011, the high-resolution camera measurements revealed
short-period (order of seconds) peaks of more than twice that value. Measurements were
taken from different locations between 2 and 7 km distance from the summit vent,
thus giving different perspectives of the gas plume. Where possible, links between
SO2 emissions and other monitored parameters are identified and interpreted in
regard to their connection to physical processes occurring in the volcanic system. |
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