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| Titel |
Inverting for volcanic SO2 flux at high temporal resolution using spaceborne plume imagery and chemistry-transport modelling: the 2010 Eyjafjallajökull eruption case study |
| VerfasserIn |
M. Boichu, L. Menut, D. Khvorostyanov, L. Clarisse, C. Clerbaux, S. Turquety, P.-F. Coheur |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 17 ; Nr. 13, no. 17 (2013-09-02), S.8569-8584 |
| Datensatznummer |
250085659
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| Publikation (Nr.) |
 copernicus.org/acp-13-8569-2013.pdf |
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| Zusammenfassung |
| Depending on the magnitude of their eruptions, volcanoes impact the
atmosphere at various temporal and spatial scales. The volcanic source
remains a major unknown to rigorously assess these impacts. At the scale of
an eruption, the limited knowledge of source parameters, including
time variations of erupted mass flux and emission profile, currently
represents the greatest issue that limits the reliability of volcanic cloud
forecasts. Today, a growing number of satellite and remote sensing
observations of distant plumes are becoming available, bringing indirect
information on these source terms. Here, we develop an inverse modelling
approach combining satellite observations of the volcanic plume with an
Eulerian regional chemistry-transport model (CHIMERE) to characterise the
volcanic SO2 emissions during an eruptive crisis. The May 2010
eruption of Eyjafjallajökull is a perfect case study to apply this method
as the volcano emitted substantial amounts of SO2 during more than
a month. We take advantage of the SO2 column amounts provided by
a vast set of IASI (Infrared Atmospheric Sounding Interferometer) satellite
images to reconstruct retrospectively the time series of the mid-tropospheric
SO2 flux emitted by the volcano with a temporal resolution of
~2 h, spanning the period from 1 to 12 May 2010. We show that no a
priori knowledge on the SO2 flux is required for this reconstruction.
The initialisation of chemistry-transport modelling with this reconstructed
source allows for reliable simulation of the evolution of the long-lived
tropospheric SO2 cloud over thousands of kilometres. Heterogeneities
within the plume, which mainly result from the temporal variability of the
emissions, are correctly tracked over a timescale of a week. The robustness
of our approach is also demonstrated by the broad similarities between the
SO2 flux history determined by this study and the ash discharge
behaviour estimated by other means during the phases of high explosive
activity at Eyjafjallajökull in May 2010. Finally, we show how
a sequential IASI data assimilation allows for a substantial improvement in
the forecasts of the location and concentration of the plume compared to an
approach assuming constant flux at the source. As the SO2 flux is an
important indicator of the volcanic activity, this approach is also of
interest to monitor poorly instrumented volcanoes from space. |
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