2-D tomography of volcanic CO<sub>2</sub> from scanning hard-target differential absorption lidar: the case of Solfatara, Campi Flegrei (Italy)
Solfatara is part of the active volcanic zone of Campi Flegrei (Italy), a densely populated urban area where ground uplift and increasing ground temperature are observed, connected with rising rates of CO<sub>2</sub> emission. A major pathway of CO<sub>2</sub> release at Camp...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-11-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | http://www.atmos-meas-tech.net/9/5721/2016/amt-9-5721-2016.pdf |
| Summary: | Solfatara is part of the active volcanic zone of Campi Flegrei (Italy), a
densely populated urban area where ground uplift and increasing ground
temperature are observed, connected with rising rates of CO<sub>2</sub> emission. A
major pathway of CO<sub>2</sub> release at Campi Flegrei is diffuse soil degassing,
and therefore quantifying diffuse CO<sub>2</sub> emission rates is of vital
interest. Conventional in situ probing of soil gas emissions with
accumulation chambers is accurate over a small footprint but requires
significant time and effort to cover large areas. An alternative approach is
differential absorption lidar, which allows for a fast and spatially
integrated measurement. Here, a portable hard-target differential absorption
lidar has been used to acquire horizontal 1-D profiles of column-integrated
CO<sub>2</sub> concentration at the Solfatara crater. To capture heterogenic
features in the CO<sub>2</sub> distribution, a 2-D tomographic map of the CO<sub>2</sub>
distribution has been inverted from the 1-D profiles. The scan was performed
one-sided, which is unfavorable for the inverse problem. Nonetheless, the
result is in agreement with independent measurements and furthermore confirms
an area of anomalous CO<sub>2</sub> degassing along the eastern edge as well as the
center of the Solfatara crater. The method may have important implications
for measurements of degassing features that can only be accessed from limited
angles, such as airborne sensing of volcanic plumes. CO<sub>2</sub> fluxes
retrieved from the 2-D map are comparable, but modestly higher than emission
rates from previous studies, perhaps reflecting an increase in CO<sub>2</sub> flux
or a more integrated measurement or both. |
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| ISSN: | 1867-1381 1867-8548 |