GMPV8.5 | Volcanic plumes: insights into volcanic emissions and their impacts on the environment, atmosphere and climate
EDI
Volcanic plumes: insights into volcanic emissions and their impacts on the environment, atmosphere and climate
Co-organized by AS4/CL1/NH2
Convener: Pasquale Sellitto | Co-conveners: Giuseppe G. Salerno, Corinna Kloss, Tjarda Roberts
Orals
| Mon, 24 Apr, 08:30–10:05 (CEST)
 
Room -2.47/48
Posters on site
| Attendance Mon, 24 Apr, 10:45–12:30 (CEST)
 
Hall X2
Orals |
Mon, 08:30
Mon, 10:45
Volcanoes release gas effluents and aerosol particles into the atmosphere during eruptive episodes and by quiescent emissions. Volcanic degassing exerts a dominant role in forcing the timing and nature of volcanic unrest and eruptions. Understanding the exsolution processes of gas species dissolved in magma, and measuring their emissions is crucial to characterise eruptive mechanism and evaluate the sub-sequent impacts on the atmospheric composition, the environment and the biosphere. Emissions range from silent exhalation through soils to astonishing eruptive clouds that release gas and particles into the atmosphere, potentially exerting a strong impact on the Earth’s radiation budget and climate over a range of temporal and spatial scales. Strong explosive volcanic eruptions are a major natural driver of climate variability at interannual to multidecadal time scales. Quiescent passive degassing and smaller-magnitude eruptions on the other hand can impact on regional climate system. Through direct exposure and indirect effects, volcanic emissions may influence local-to-regional air quality and seriously affect the biosphere and environment. Volcanic gases can also present significant hazards to populations downwind of an eruption, in terms of human, animal and plant health, which subsequently can affect livelihoods and cause socio-economic challenges. Gas emissions are measured and monitored via a range of in-situ and remote sensing techniques, to gain insights into both the subterranean-surface processes and quantify the extent of their impacts. In addition, modelling of the subsurface and atmospheric/climatic processes, as well as laboratory experiments, are fundamental to the interpretation of field-based and satellite observations.

This session focuses on the state-of-the-art and interdisciplinary science concerning all aspects of volcanic degassing and impacts of relevance to the Volcanology, Environmental, Atmospheric and Climate sciences (including regional climate), and Hazard assessment. We invite contributions on all aspects of volcanic plumes science, their observation, modelling and impacts. We welcome contributions that address issues around the assessment of hazards and impacts from volcanic degassing both in crises and at persistently degassing volcanoes.

Orals: Mon, 24 Apr | Room -2.47/48

Chairpersons: Pasquale Sellitto, Stefano Corradini
08:30–08:35
Ground-based observations
08:35–08:45
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EGU23-9143
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Virtual presentation
Dario Delle Donne, Giorgio Lacanna, Marcello Bitetto, Giacomo Ulivieri, Maurizio Ripepe, and Alessandro Aiuppa

Volcanic degassing, a persistent manifestation of active volcanoes, provides crucial information on the dynamics of the magmatic feeding systems, and allows identifying the phases of volcanic unrest in the runup to volcanic eruptions. While thus determining volcanic degassing rates is a central topic in modern Volcanology, direct volcanic gas flux observations by classic spectroscopic techniques are challenged by (i) the need of adequate illumination (by sunlight) and clear weather conditions (ii) difficulties in robustly estimating plume speed velocity and transport direction, and (iii) a variety of optical and radiative transfer issues. Because of these, volcanic gas flux records are often sparse and incomplete, and affected by intrinsic noise that may prevent from fully resolving the gas emission changes associated with changing volcanic activity. To overcome such limitations, measuring the infrasound produced by the expansion of over-pressurized volcanic gas in the atmosphere, using infrasonic arrays, offers as a promising alternative/complementary tool to quantify and locate degassing at active volcanoes. Here, we report on 2-year long (April 2017—March 2019) period of combined measurements of the SO2 flux and of volcano-acoustic emissions produced by regular mild persistent strombolian activity and passive degassing of Stromboli Volcano (Sicily, Italy). These were obtained by a permanent monitoring SO2 camera and a five-element short-aperture (~300 m) infrasonic array. Our results highlight substantial temporal changes in degassing activity, that reflect the recurrent episodes of activations/inactivation of multiple distinct degassing sources within the crater area, as coherently tracked by SO2 and infrasound together. A simple waveform modeling of the infrasonic record, assuming a monopole acoustical source, suggests that infrasonic degassing, comprising of explosive events and continuous puffing activity, dominates the total persistent degassing budget as tracked by the SO2 camera.

How to cite: Delle Donne, D., Lacanna, G., Bitetto, M., Ulivieri, G., Ripepe, M., and Aiuppa, A.: Quantifying volcanic gas emission rates from infrasound and SO2 cameras: potentials, limitations, and volcanological implications., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9143, https://doi.org/10.5194/egusphere-egu23-9143, 2023.

08:45–08:55
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EGU23-11832
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On-site presentation
Stefano Corradini, Giuseppe Salerno, Robin Campion, Lorenzo Guerrieri, Luca Merucci, and Dario Stelitano

During the 14th IAVCEI Field Workshop held in Peru from 6 to 14 November 2022, SO2 plume measurements were carried out remotely in the volcanic plume of Sabancaya volcano. Sabancaya is an active stratovolcano located in southern Peru (15.787°S, 71.857°W), Sabancaya’s first historical record of an eruption dates to 1750 and the most recent eruption began in November 2016. Volcanic activity consist of rhythm vulcanian explosions, which produce a gas-ash rich plumes which rose few km above the summit terrace. On 10 and 11 November 2022, side-by-side observation by UV and TIR ground-based cameras were remotely carried out with the object to observe the passive and active SO2 burden from the volcanic plume of Sambacaya. Two UV cameras systems were employed observing the volcanic plume at 2- and 5-seconds time steps and calibrating SO2 amounts by coupling SO2 DOAS inverted column densities ad and SO2-quartz cell amounts. The TIR camera (named VIRSO2) is a novel system developed for the detection of volcanic plumes, the estimation of the height and the determination of columnar content and the SO2 flux. It allows acquisition of high frequency data both during the day and at night. It is equipped with 3 cameras, two broadband TIR (7-14 micron) and a VIS, capable of acquiring data simultaneously. For the quantitative estimation of SO2, an 8.7 μm filter is installed in front of one of the TIR camera. Retrieved cameras products were cross-compared and validated in order to determinate limit an uncertainty of both methods and results were also compared with those obtained by S5p-TROPOMI instrument.

Preliminary results show a feasible strength between the three ground and space-based techniques. Within the uncertainties of each method, differences between inverted SO2 column densities and emission rates arise from field of view geometrical sampling set-up and radiative transfer. Results gathered in this study prove the promising application of ground-based TIR in volcanic plume SO2 observation.

How to cite: Corradini, S., Salerno, G., Campion, R., Guerrieri, L., Merucci, L., and Stelitano, D.: Remote SO2 flux by UV and TIR ground based cameras at Sabancaya volcano (Peru), cross comparison and validation with satellite data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11832, https://doi.org/10.5194/egusphere-egu23-11832, 2023.

Satellite observations
08:55–09:05
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EGU23-5423
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ECS
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On-site presentation
Smita Rani Panda, Marie Boichu, Yevgeny Derimian, Oleg Dubovik, and Abhinna Kumar Behera

Volcanic sulfur dioxide (SO2) is a gaseous precursor that is transformed into secondary sulfate aerosols (SO42-) by several intricate chemical and physical atmospheric processes. It is currently unclear how quickly sulfate aerosols are produced in volcanic plumes, particularly in tropospheric plumes. We jointly analyze Aura/OMI SO2 observations to constrain the sulfur-rich emissions and identify the volcanic plume dispersion pattern as well as multi-angle, multi-wavelength, and polarizing PARASOL/POLDER-3 observations that are particularly sensitive to fine mode particles to gain a better understanding of the lifecycle of volcanic sulfate aerosols. The GRASP/Component[1] (Generalized retrieval of Aerosol and Surface Properties) algorithm gives us details about the soluble and insoluble aerosol components in both fine and coarse modes based on their complex refractive indices in addition to standard optical characteristics. In order to provide insight into SO2 to particle conversion rate, we analyze the degassing of the Kilauea volcano (Hawaii, USA) between 2006 to 2012, which includes periods of passive and eruptive degassing.

We demonstrate that Kilauea SO2-rich pixels from OMI measurements are broadly collocated with poorly-absorbing fine aerosol-rich pixels from POLDER measurements (fine AOD (440nm) ranging from 0.1 to 0.4, SSA (440nm) ranging from 0.95 to 1.0). We show that these volcanic particles also differ from long-distance transported man-made and natural fine-absorbing particles seen across the Kilauea domain from the Asian region in terms of their absorption characteristics. We, therefore attribute these fine mode particles to sulfate aerosols that result from the conversion of Kilauea SO2 emissions.

In comparison to SO2-rich plumes, Kilauea aerosol-rich plumes have a significantly wider spread and are characterized by an excess anomaly in fine AOD and high SSA values. Irrespective of the degassing strength, a pattern consistent with the oxidation of SO2 to secondary sulfate aerosols is observed where the SO2 concentration gradually drops with plume dispersion while the fine AOD gradually increases, peaking at a distance of around 800–3000 km from the Kilauea source. Depending on the intensity of volcanic activity, the season, and enduring local meteorological conditions, different time scales for oxidation of SO2 and geographical dispersion of the Kilauea aerosol plumes are observed. We conducted additional analysis on the coarse AOD and coarse components to look for ash signals inside the plume. Furthermore, the complex refractive index of Kilauea particles, retrieved by the GRASP/Component algorithm, indicates an imaginary part (0.003-0.005) that is slightly higher than that of volcanic basaltic ash, as determined by laboratory experiments, while the real part (1.49-1.52) lies well in between pure sulfate (1.40-1.46) and basaltic ash (1.56-1.63). These refractive index values imply that Kilauea particles are not pure sulfate aerosols but instead contain some spectrally absorbing elements that may point to the existence of fine ash or sulfate-coated ash particles within the plume.

[1] Li, L., Dubovik, O., Derimian, Y., Schuster, G. L., Lapyonok, T., Litvinov, P., Ducos, F., Fuertes, D., Chen, C., Li, Z., Lopatin, A., Torres, B., and Che, H.: Retrieval of aerosol components directly from satellite and ground-based measurements, Atmos. Chem. Phys., 19, 13409–13443, https://doi.org/10.5194/acp-19- 13409-2019, 2019.

How to cite: Panda, S. R., Boichu, M., Derimian, Y., Dubovik, O., and Behera, A. K.: Insight into the conversion of SO2 to sulphate aerosols in volcanic plumes from the joint analysis of hyperspectral OMI and multi-angular polarimetric POLDER satellite observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5423, https://doi.org/10.5194/egusphere-egu23-5423, 2023.

09:05–09:15
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EGU23-2364
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ECS
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On-site presentation
Alexandre Deguine, Lieven Clarisse, Hervé Herbin, and Denis Petitprez

Hyperspectral infrared sounders like IASI are used to track and quantify volcanic ash in the atmosphere. The retrieval process of physical quantities like particle radius and mass depends critically on the assumed spectrally dependent complex refractive indices that are used. Traditionally, the Pollack et al. (1973) dataset were used almost exclusively. These indices are however based on measurements of rock slabs and in recent years two datasets have become available from laboratory measurements of ash in suspension, the Reed et al. (2018) and Deguine et al. (2020) dataset. In this work, we compare for the first time the three most important datasets of CRI with respect to the three most common ash types (basaltic, andesitic and rhyolitic). The results show significant influence of the dataset used on the retrieved physical quantities. When it comes to basaltic and andesitic ash, both the Deguine and Reed samples outperform Pollack in terms of able to reconstruct the satellite observed spectra. However, all datasets overestimate the extinction near 1250 cm−1, which could possibly be related to the lack of sensitivity of spectrometers (water vapour continuum) leading to a poor signal over noise ratio in this spectral region. While this is not a guarantee that the retrieved quantities are closer to the physical reality, being able to reconstruct the observed spectra is a prerequisite of constructing a consistent physical model. Finally, a case study on the 7 May 2010 plume of the Eyjafjallajokull eruption is presented. For this case study, the differences are found to be mostly related in retrieved altitudes. It is clear that while the availability of CRI based on ash suspended in air is an important milestone, a lot of further research is needed to strengthen the theoretical basis of infrared retrievals of volcanic ash. A comprehensive database of reliable in-situ measurements of volcanic clouds would in this perspective be most welcome.

A. Deguine, D. Petitprez, L. Clarisse, S. Gudmundsson, V. Outes, G. Villarosa, and H. Herbin, “Complex refractive index of volcanic ash aerosol in the infrared, visible, and ultraviolet,” Applied Optics, vol. 59, no. 4, p. 884, jan 2020.

J. B. Pollack, O. B. Toon, and B. N. Khare, “Optical properties of some terrestrial rocks and glasses,” Icarus, vol. 19, no. 3, pp. 372–389, jul 1973.

B. E. Reed, D. M. Peters, R. McPheat, and R. G. Grainger, “The complex refractive index of volcanic ash aerosol retrieved from spectral mass extinction,” Journal of Geophysical Research, vol. 123, no. 2, pp. 1339–1350, jan 2018.

How to cite: Deguine, A., Clarisse, L., Herbin, H., and Petitprez, D.: Measuring volcanic ash optical properties with high-spectral resolution infrared sounders: role of refractive indices, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2364, https://doi.org/10.5194/egusphere-egu23-2364, 2023.

Modelling
09:15–09:25
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EGU23-12069
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ECS
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On-site presentation
Sascha Bierbauer, Gholam Ali Hoshyaripour, Julia Bruckert, Daniel Reinert, and Bernhard Vogel

Explosive volcanic eruptions emit large amounts of solid and gaseous materials into the atmosphere, thereby affect weather and climate and pose hazards to human health and aviation. To constrain those impacts it is important to understand dynamical, microphysical and chemical evolution of the eruption plumes. Especially the density of a plume and atmospheric conditions control the dynamical development of an eruption plume. To simulate those plumes correctly the flow field has to be described as a multi-constituent multiphase flow system. This is realized in eruption plume models but not in the conventional atmospheric models. The latter neglect the partial density of ash particles in relation to total air mass and cannot treat for the effect of ash particles on dynamics during simulations. To overcome this limitation, we use a modified version of ICOsahedral Nonhydrostatic model with Aerosols and Reactive Trace gases (ICON-ART) in which we extended the existing equation set. This version of ICON-ART can consider a source of total mass during the eruption as well as a mass sink due to sedimentation of ash and other constituents. The mass source is accounted by an additional source term for total density, and the mass sink is accounted by implementing the lower boundary condition of the vertical velocity at the surface. This leads to a conserved dry air mass and changing total air mass, which affects dynamics and is crucial for handling multiphase flows correctly. Additionally, a momentum forcing as well as a temperature forcing cause the strong updraft within the plume region.

We simulated the real case of the Raikoke eruption in 2019 in a LES-mode for more detailed investigations of the plume. In this experiment, in addition to ash, we also emit water vapor which might lead to an additional upward motion in the convective plume region due to latent heat release when clouds develop. The results show that the model is able to reproduce the observed plume geometry vertically and horizontally. Moreover, we simulated gravity waves that developed during the eruption around the volcano. In combination with microphysics and aerosol dynamics, the new implementations in ICON-ART enable detailed investigations of volcanic plume development across scales.

How to cite: Bierbauer, S., Hoshyaripour, G. A., Bruckert, J., Reinert, D., and Vogel, B.: Explicit simulation of volcanic eruption plumes in atmospheric models: first results and implications, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12069, https://doi.org/10.5194/egusphere-egu23-12069, 2023.

09:25–09:35
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EGU23-7268
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ECS
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On-site presentation
Giuseppe Castorina, Agostino Semprebello, Alessandro Gattuso, Francesco Italiano, Giuseppe Salerno, Pasquale Sellitto, and Umberto Rizza

During the summer of 2019, both Mt. Etna and Stromboli volcanoes in Sicily were in the stage of no ordinary activity. Mt. Etna was featured by mild strombolian activity from the summit South East Crater producing a moderate SO2–ash rich plume 4 km above sea level (asl). Meanwhile, at 120 km far from Etna, on 3 July and 28August, the ordinary and typical mild explosive eruptive activity of Stromboli was interrupted by two paroxysms. Both events were characterized by pyroclastic flows and consistent emission of ash–SO2 rich plume, which spread up to height of 5–6 km asl.
In this work, we explored the spatial dispersion of the volcanic plumes released by both Mt. Etna and Stromboli on August 28 by employing the Weather Research and Forecasting Chemistry (WRF–Chem) model. The simulation was specifically configured and run by considering the time-variable Eruptive Source Parameters (ESPs) related to the SO2 flux data for Stromboli and Mount Etna observed from ground by the FLAME DOAS scanning spectrometers network.
In order to assess the predictive performance of the WRF–Chem model, the simulated SO2 dispersion maps were compared with data retrieved on 28 August from TROPOMI and OMI sensors onboard Sentinel–5p and Aura satellites. The results show a good agreement between WRF–Chem and satellite data. In fact, the simulated total mass of the emitted SO2 from the two volcanoes has the same order of magnitude as the satellite data. However, for the case of Stromboli, the total SO2 mass predicted by the WRF–Chem simulation is underestimated; this is likely due to inhibition of the real syn-eruptive SO2 detection by FLAME due to the extreme ash–rich volcanic plume released during the paroxysm.
In conclusion, the results of these two test–cases demonstrate the feasibility of WRF–Chem model with a time-variable ESPs in reproducing different levels of volcanic SO2 and their dispersion into the atmosphere. For these reasons, our approach could represent an effective support for the assessment of local–to-regional air quality and flight security and, in case of particularly intense events, also on a global scale.

How to cite: Castorina, G., Semprebello, A., Gattuso, A., Italiano, F., Salerno, G., Sellitto, P., and Rizza, U.: Dispersion modeling of the volcanic sulfur dioxide plumes from the simultaneous eruptive activity of Stromboli and Mt Etna on 28 August 2019, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7268, https://doi.org/10.5194/egusphere-egu23-7268, 2023.

Very large volcanic eruptions
09:35–09:45
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EGU23-7369
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ECS
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Highlight
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On-site presentation
Clair Duchamp, Bernard Legras, Pasquale Sellitto, Aurélien Podglajen, Elisa Carboni, Richard Siddans, Jens-Uwe Grooss, Felix Ploeger, and Sergey Khaykin

We use a combination of seven space-borne instruments to study the unprecedented stratospheric plume after the Tonga eruption of 15 January 2022.

The aerosol plume was initially formed of two clouds at 30 and 28 km mostly composed of submicron-sized sulfate particles, without ashes washed-out within the first day following the eruption. The large amount of injected water vapour led to a fast conversion of SO2 to sulfate aerosols and induced a descent of the plume to 24-26 km over the first 3 weeks by radiative cooling. Whereas SO2 has returned to background levels by the end of January, volcanic sulfates and water still persisted after 6 months, mainly confined between 35°S and 20°N until June due to the zonal symmetry of the summer stratospheric circulation at 22-26 km. Sulfate particles, undergoing hygroscopic growth and coagulation, sediment and gradually separate from the moisture anomaly entrained in the ascending branch Brewer-Dobson circulation. Sulfate aerosol optical depths derived from the IASI infrared sounder show that during the first two months the aerosol plume was not simply diluted and dispersed passively but rather organized in concentrated patches. Space-borne lidar winds suggest that those structures, generated by shear-induced instabilities, were associated with vorticity anomalies that may have enhanced the duration and impact of the plume.

Reference: ACP Highlight, DOI: 10.5194/acp-22-14957-2022

How to cite: Duchamp, C., Legras, B., Sellitto, P., Podglajen, A., Carboni, E., Siddans, R., Grooss, J.-U., Ploeger, F., and Khaykin, S.: The evolution and dynamics of the sulfate aerosol plume in the stratosphere after the exceptional Tonga eruption of 15 January 2022, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7369, https://doi.org/10.5194/egusphere-egu23-7369, 2023.

09:45–09:55
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EGU23-8559
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ECS
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On-site presentation
Lucy Blennerhassett and Dr. Emma Tomlinson

Mercury is a significant volcanic volatile species from effusive and explosive activity1. Understanding its emission to the atmosphere from volcanic activity, aids our understanding of the global mercury cycle and its environmental impacts. Sedimentary and ice core records can be archives of these mercury enrichments2,3.

The Laki 1783-84 AD fissure eruption in Iceland was significant due to its voluminous outpouring of basaltic lava, copious sulphur emissions and widespread environmental effects locally and across the Northern Hemisphere4,5. Extreme weather events were recorded in Europe and North America, owing to a veil of sulphur dioxide that remained at the tropopause for over a year5. Due to the phreatomagmatic and thus explosive nature of Laki, a significant eruption plume was produced4. As such, cryptotephra shards have been located at distal locations from Iceland including ice cores in Svalbard and Greenland6,7 and in an Irish woodland peat at Brackloon Wood, Co. Mayo8. There is evidence to suggest significant heavy metal emission to the atmosphere during the Laki eruption, however these records are currently restricted to Greenland ice cores9. Previous heavy metal findings linked to Laki do not include mercury, despite its significance as a volcanic volatile, and a potentially environmentally damaging heavy metal. Therefore, to expand our knowledge of the Laki 1783-84 AD eruption plume, its associated emissions, and environmental consequences we returned to the woodland peat site in Brackloon Wood, Co. Mayo, Ireland.

Analysis of a 50 cm peat core using an AMA 254 mercury analyser was combined with a novel technique to find tephra using BSE (back scattered electron) imaging and geochemical discrimination using SEM-EDX (scanning electron microscopy-energy dispersive x-ray). The Laki tephra is successfully located using this method and coincides with a visible enrichment in mercury relative to background concentrations and organic matter. An age-depth model developed using the tephra layer and two radiocarbon dates indicate a strong likelihood that such enrichments are a product of volcanic emission. Such a finding can expand our understanding of heavy metal deposition during Laki 1783-84 AD away from the poles and to our knowledge, demonstrates the first direct exploration of mercury enrichment in distal peat for this eruption. As a secondary test of volcanic volatile enrichment, trace element analysis of the same bulk peat will be conducted to explore enrichments in other volcanic volatiles such as sulphur, cadmium, lead, copper and zinc.

 

1. Pyle, D. M. & Mather, T. A. Atmos. Environ. 37, 5115–5124 (2003).

2. Schuster, P. F. et al.,. Environ. Sci. Technol. 36, 2303–2310 (2002).

3. Roos-Barraclough, F. et al.,. Earth Planet. Sci. Lett. 202, 435–451 (2002).

4. Thordarson, T. & Self, S. Bull. Volcanol. 55, 233–263 (1993).

5. Thordarson, T. & Self, S., J. Geophys. Res 108, 4011 (2003).

6. Kekonen, T. et al., Polar Res. 24, 33–40 (2005).

7. Wei, L. et al., Geophys. Res. Lett. 35, L16501 (2008).

8. Reilly, E. & Mitchell, F. J., Holocene 25, 241–252 (2015).

9. Hong, S. et al., Earth Planet. Sci. Lett. 144, 605–610 (1996).

 

How to cite: Blennerhassett, L. and Tomlinson, Dr. E.: Laki 1783-84 AD tephra linked mercury enrichment in peat at Brackloon Wood, Mayo, Ireland., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8559, https://doi.org/10.5194/egusphere-egu23-8559, 2023.

09:55–10:05
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EGU23-4626
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ECS
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Virtual presentation
Deming Kong, Weijia Feng, jiawen Yang, Chuang Bao, and Min-Te Chen

Large volcanic eruptions have significant impacts on climate and environmental changes. The deposition of tephra in marine sediments may serve as an eruption recorder, but it has not been extensively studied in the western Pacific. This study explored a millennial-scale tephra event-stratigraphy with multiple indicators in a sediment core collected from the eastern South China Sea (SCS) basin. The magnetic susceptibility (MS), Fe and Mn concentration determined by X-ray fluorescence (XRF), and identification of individual ash particles were used to identify tephra layers and reconstruct the history of volcanic activity. Nine visible volcaniclastic units (VVU) and two cryptotephra layers have been identified based on their distinct features, as manifested by high MS, Fe, and Mn concentrations, and single-peak grain size distribution. The VVUs and cryptotephra layers reveal elevated volcanic activities. Using the radiocarbon age model and oxygen isotope stratigraphy, these episodes could roughly correspond to the following periods: 1-11 ka, 16-17 ka, 27-31 ka, 41-42 ka, 45-46 ka, 49-50 ka, 77-80 ka, 90-91 ka, 97-99 ka, 116-126 ka, and 132-140 ka. The alkenone-derived SST has significant glacial cycles and good synchronicity with other SCS SST records, which could partially help build the preliminary age model. Despite possible age errors larger than 1 kyr, the discovery and timing of tephra layers provide a preliminary framework to further investigate the impact of historical volcanic eruptions on climate changes.

How to cite: Kong, D., Feng, W., Yang, J., Bao, C., and Chen, M.-T.: A millennial-scale tephra event-stratigraphic record of the South China Sea since the penultimate interglacial, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4626, https://doi.org/10.5194/egusphere-egu23-4626, 2023.

Posters on site: Mon, 24 Apr, 10:45–12:30 | Hall X2

Chairpersons: Hugues Brenot, Alexandre Deguine, Agostino Semprebello
X2.131
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EGU23-3795
Sheng-Rong Song

Volcanic eruptions used to cause huge disasters which usually bring about many fatalities and property damages, especially a big city near the volcanoes. The Taipei metropolitan city is located at the foot of Tatun Volcano Group (TVO), which has been identified as an active volcano. Meanwhile, several volcanic islands are distributed in the offshore of northern Taiwan, which may be the active volcanoes. Thus, the past eruptive behaviors and mechanisms, characteristics of products, volcanic history and activity, etc.

Based on the field observations, geomorphologic analyses, characteristics of ejecta, as well as the cases of world volcanoes, the explosive craters distributed in both sides of Chihsingshan volcano were produced by the phreatic eruption. Generally, two models of phreatic eruption have been proposed. One is a deeper hydrothermal system fed by magmatic gases being sealed and produces overpressure sufficient to drive explosive eruptions, and the other where magmatic gases are supplied via open-vent degassing to a near-surface hydrothermal system, vaporizing liquid water which drives the phreatic eruptions. The mechanism of Chihsingshan phreatic eruption is similar to the type I, which has hydrothermal reservoir underneath the volcano. Comparing other types of phreatic eruption in the world, for example, Mt. Ontake (Japan)、Inyo Craters (USA) and Tarawera Rift (New Zealand), they have similar common characteristics, (i) occurred in rifting conditions, (ii) heat source from magma intruded along the faults, (iii) had water body, such as groundwater, lakes or hydrothermal fluids, etc. near the conduit of magma. The geology and mechanism of phreatic eruption in the Chihsingshan volcano is more or less similar to the 2014 phreatic eruption of Mt. Ontake, Japan.

How to cite: Song, S.-R.: Characteristics of Latest Eruption in the Tatun Volcano Group, North Taiwan, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3795, https://doi.org/10.5194/egusphere-egu23-3795, 2023.

X2.132
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EGU23-7027
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ECS
Adeline Aroskay, Erwan Martin, Slimane Bekki, Joël Savarino, Jean-Luc Le Pennec, Abidin Temel, Nelida Manrique, Rigoberto Aguilar, Marco Rivera, and Sophie Szopa

On Earth, most of the nitrogen (N) accessible for life is trapped in dinitrogen (N2), which is the most stable atmospheric molecule. In order to be metabolised by living organisms, N2 has to be converted into assimilable forms, also called fixed N. Nowadays, nearly all the N-fixation is achieved through biological and anthropogenic processes. However, in early environments of the Earth, before the emergence of life, N-fixation must have occurred via natural abiotic processes. Electrical discharges, including from thunderstorms and also lightning associated with volcanic eruptions is one of the most invoked processes. The occurence of volcanic lightning during explosive eruptions is frequent, and convincing laboratory experimentations support the role of this phenomenon, however no evidence of substantial N-fixation has been found in volcanic records.
Here we report on the discovery of large amounts of nitrates in volcanic deposits from Neogene caldera-forming eruptions, which are well correlated with the concentrations of species directly emitted by volcanoes such as sulphur and chlorine. The multi-isotopic composition (δ18O, Δ17O) of the nitrates reveals that they originate from the atmospheric oxidation of nitrogen oxides formed by volcanic lightning that occur during the eruption. According to these volcanic nitrate records, our first estimates suggest that about 60 Tg of N can be fixed during a large explosive event. Our findings hint at a unique role potentially played by subaerial explosive eruptions in supplying essential ingredients for the emergence of life on Earth.

How to cite: Aroskay, A., Martin, E., Bekki, S., Savarino, J., Le Pennec, J.-L., Temel, A., Manrique, N., Aguilar, R., Rivera, M., and Szopa, S.: First archive of extensive N-fixation by volcanic lightning and implications for the prebiotic Earth, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7027, https://doi.org/10.5194/egusphere-egu23-7027, 2023.

X2.133
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EGU23-9128
Jose Pacheco, Diogo Henriques, Sérgio Oliveira, Alexandra Moutinho, Fátima Viveiros, Diamantino Henriques, Pedro Hernández, and Nemesio Pèrez

The Tajogaite eruption of Cumbre Vieja volcano, in 2021, was a basaltic fissure eruption characterised by a variety of eruptive styles ranging from the predominantly strombolian activity, to lava fountaining, ash emission and effusive activity. The eruption lasted nearly 3 months, produced an extensive lava field and about 45.106 m3 of tephra. Although its intensity varied throughout the entire duration of the eruption, the eruptive plume had a typical height of about 3500 m asl and reached a maximum of 8500 m asl just hours before the end of the eruption, on the 13th of December. Ash is, therefore, a significant hazard to consider not only during the eruption, but also on the post-eruption phase.

To measure ash in the air around the volcano, during the last stage of the eruption and the following weeks, an experiment was devised based on a proximal network of several ground-based low-cost sensors, measuring suspended particulate matter (PM10, PM2.5) concentration, air temperature, and relative humidity.

The results showed that, during the documented period, the daily mass concentration of particulate matter in the air reproduced the peak on the eruptive column high at the end of the eruption. After the eruption several significant resuspension events were detected simultaneously in several stations; in addition, after the eruption, a major event of “calima” dust intrusion largely exceeded all recorded eruptive events. Overall, even after the eruption, the 24-hour average exposure to PM2.5 surpassed the guidelines of the World Health Organization.

 

 

This work was partially funded by FCT – Fundação para a Ciência e Tecnologia, under project SONDA - Synchronous Oceanic and Atmospheric Data Acquisition (PTDC/EME-SIS/1960/2020) and INTERREG MAC under the project VOLRISKMAC-II - Fortalecimiento de las capacidades de I+D+i para el desarrollo de la resiliencia frente a emergencias volcánicas en la Macaronesia.

How to cite: Pacheco, J., Henriques, D., Oliveira, S., Moutinho, A., Viveiros, F., Henriques, D., Hernández, P., and Pèrez, N.: Ground-based volcanic ash detection with low-cost sensors – a case study at the 2021 Cumbre Vieja eruption, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9128, https://doi.org/10.5194/egusphere-egu23-9128, 2023.

X2.134
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EGU23-11407
Jérémie Vasseur, Fabian Wadsworth, Alice Paine, and Donald Dingwell

Sulfate aerosols are a primary driver of climate impacts during and following volcanic eruptions and form from erupted SO2 gas. However, the amount of SO2 that is delivered to the stratosphere is not clearly related to the amount dissolved in the magma (the ‘sulfur excess problem’). Therefore, magma properties and eruption magnitude are not necessarily predictive of climate impacts from eruptions, which is exacerbated by the as-yet unknown importance of the insulated, hot transport pathway. During a magnitude 6 explosive volcanic eruption there is up to 100 seconds of transport between the magma fragmentation depth – where volcanic ash is formed and the mixture accelerates – and the Earth’s surface. Here, we present a numerical implementation of a theoretical framework which predicts the rapid reactions between gases and volcanic ash in this transport interval, which include: (1) iron oxidation state changes; (2) SO2 uptake via calcium sulfate surface crystallization; (3) HCl uptake via NaCl surface crystallization; and (4) incipient nanolite crystallization that may be related to (1). In all cases, these processes are rate-limited by a suite of diffusive exchanges between the ash bulk and surface, for which our model solves. To demonstrate the upscaled importance of these processes, we couple our models to volcanic plume simulations (using a 1991 Pinatubo baseline simulation), and output the bulk SO2 that can be captured by ash. We find that depending on the source parameters of the eruption, anywhere between 30 and 100 wt.% of the total erupted SO2 can be removed from the plume gas and captured by ash. This effectively changes the sink of SO2 from the stratosphere to the hydrosphere, as CaSO4 crystals are soluble and ultimately wash into the environment following ash deposition. We propose that these hot sulfur scrubbing processes may be crucial in mediating SO2 delivery to the atmosphere, and therefore may explain much of the complexities associated with correlating eruption magnitude with climate impacts in the recent past or back into the Last Glacial period.

How to cite: Vasseur, J., Wadsworth, F., Paine, A., and Dingwell, D.: Hot volcanic ash filters eruptive SO2 during hot transport in conduits and the lower plume: A predictive model with implications for the climate impacts of volcanic eruptions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11407, https://doi.org/10.5194/egusphere-egu23-11407, 2023.

X2.135
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EGU23-13755
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ECS
Anna Kampouri, Vasilis Amiridis, Ondřej Tichý, Nikolaos Evangeliou, Stavros Solomos, Anna Gialitaki, Eleni Marinou, Antonis Gkikas, Emmanouil Proestakis, Simona Scollo, Luca Merucci, Lucia Mona, Nikolaos Papagiannopoulos, and Prodromos Zanis

Modeling the dispersion of volcanic particles released during explosive eruptions is crucially dependent on the knowledge of the source term of the eruption and the source strength as a function of altitude and time. Forecasting volcanic ash transport is vital for aviation but rather inaccurate for quantitative predictions of the fate of volcanic particle emissions. Here we demonstrate an inverse modeling framework that couples the output of a Lagrangian dispersion model with remote sensing observations to estimate the emission rates of volcanic particles released from the Etna eruption. We use an inversion algorithm (Tichy et al., 2020) where the distance between the model and observations is optimized under the assumption that the source term is either sparse or smooth. The Bayesian formalism allows the algorithm to estimate these characteristics together with the source term itself and thus normalize the inversion problem. This methodology uses source receptor relationships as an input from the FLEXPART (flexible particle dispersion) model constrained by ground-based Lidar measurements and satellite observations of SO2 and ash emissions. The case study analyzed here refers to the Etna eruption on 12 March 2021, with the volcanic plume being well captured by the lidar measurements of the PANGEA observatory located at Antikythera island in southwest Greece. A dense aerosol layer, suspending in the height range between 7.5 and 12.5 km (19:30 - 21:30 UTC), has been captured by the PollyXT lidar. For the inversion simulations, we also use data acquired by the Spin-stabilised Enhanced Visible and Infrared Imager (SEVIRI) instrument, mounted on the Meteosat Second Generation (MSG) geostationary satellite. The aforementioned observations serve as a priori source information to estimate the volcanic ash and SO2 source strength, depending on altitude and time, coupled with the output of the FLEXPART model. Our results are efficient for real-time application and could supply ash forecasting models with an accurate estimation of the mass rate of very fine ash during explosive eruptions. Improved forecasts of the dispersed volcanic plumes following the suggested inverse modeling framework would then allow for more effective emergency preparedness for aviation to ensure safety during volcanic eruptions.

 

This research was also supported by the following projects: ERC grant D-TECT (agreement no. 725698); EU H2020 E-shape project (Grant Agreement n. 820852); PANCEA project (MIS 502151) under the Action NSRF 2014-2020, co-financed by Greece and the European Union. The research was supported by data and services obtained from the PANhellenic Geophysical Observatory of Antikythera (PANGEA) of the National Observatory of Athens (NOA), Greece. O. Tichy was supported by the Czech Science Foundation, grant no. GA20-27939S.

 

Tichy, O.; Ulrych, L.; Smidl, V.; Evangeliou, N.; Stohl, A. On the tuning of atmospheric inverse methods: comparisons with the European Tracer Experiment (ETEX) and Chernobyl datasets using the atmospheric transport model FLEXPART, Geosci. Model Dev. (2020), 13, 5917-5934.

How to cite: Kampouri, A., Amiridis, V., Tichý, O., Evangeliou, N., Solomos, S., Gialitaki, A., Marinou, E., Gkikas, A., Proestakis, E., Scollo, S., Merucci, L., Mona, L., Papagiannopoulos, N., and Zanis, P.: Inversion techniques on volcanic emissions and the use for quantitative dispersion modeling: The case of Etna eruption on 12 March 2021, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13755, https://doi.org/10.5194/egusphere-egu23-13755, 2023.

X2.136
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EGU23-14820
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ECS
Jordi Van Mieghem, Hugues Brenot, Benoît Smets, and Nicolas Theys

Sensitive and accurate detection of SO2 from remote sensing is essential to monitor volcanic degassing. The main objective of this study is to understand the dynamics of SO2 gas emissions at open-vent volcanoes between major eruptive events, using Sentinel-5P TROPOMI-based SO2 measurements.

Time-series of SO2 mass are analysed at 10 open-vent volcanoes (Ambrym, Erebus, Erta Ale, Kilauea, Masaya, Nyamuragira, Nyiragongo, Stromboli, Villarica, Yasur) using a newly developed TROPOMI SO2 product generated by the Covariance Based Retrieval Algorithm (COBRA; Theys et al., 2021). Compared to the current operational SO2 TROPOMI product (which uses the Differential Optical Absorption Spectroscopy technique), the COBRA dataset has improved performances and reduce both the noise and bias on the data, allowing a more refined study of degassing from open-vent volcanoes.

Time-series have been obtained for SO2 emissions over a period from 2018 to early 2023. For the 10 selected persistently active volcanoes, the SO2 behaviours are analysed and compared, showing cyclic and sporadic variations, as well as peaks of emission when a flank or major eruption occur. Patterns in SO2 time-series during and between major eruptive events are discussed to assess the potential use (and limitations) of these measurements as a tool for early warning and volcanic crisis management.

Reference:

Theys, N., Fioletov, V., Li, C., De Smedt, I., Lerot, C., McLinden, C., Krotkov, N., Griffin, D., Clarisse, L., Hedelt, P., Loyola, D., Wagner, T., Kumar, V., Innes, A., Ribas, R., Hendrick, F., Vlietinck, J., Brenot, H., Van Roozendael, M. (2021). A sulfur dioxide Covariance-Based Retrieval Algorithm (COBRA): application to TROPOMI reveals new emission sources. Atmospheric Chemistry and Physics, 21(22), 16727-16744.

How to cite: Van Mieghem, J., Brenot, H., Smets, B., and Theys, N.: Pattern of volcanic degassing at open-vent volcanoes using TROPOMI SO2 time-series from COBRA retrievals, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14820, https://doi.org/10.5194/egusphere-egu23-14820, 2023.

X2.137
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EGU23-15216
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ECS
Celine Mandon and Andri Stefansson

Despite our perception of gold as a shiny precious metal, a small amount of gold is actually transported by magmatic gases and emitted in the atmosphere at most volcanoes on Earth. This gaseous transport is made possible by the very nature of volcanic gases: high-temperature non-ideal water vapor-dominated mixture of gases, also containing other major constituents such as sulfur, carbon dioxide and halogens. This combination allows for volatile transport of virtually all elements from the periodic table, through the formation of gaseous compounds between trace elements and major gas species. However, the complexity of volcanic gases also makes them difficult to apprehend; little is known on the solubility and behavior of trace elements. Moreover, the gas composition varies from one volcano to another, while changes in pressure and temperature occur between gas exsolution from the magma and emission at the surface. Interactions between the gas phase and surrounding rocks and fluids can furthermore affect volcanic gases on their way to the surface. In this work, we explore the transport processes controlling the abundance of trace elements in volcanic gases. We use major and trace element composition from fumarolic gases from Vulcano, Italy sampled over a 14-year period and during both background emissions and unrest. We also work with a compilation of high-temperature gas compositions, from fumaroles and volcanic plumes, from various tectonic settings. This data is then used for thermochemical calculations using the HSC Chemistry software. We will explore the factors that affect the trace element transport in volcanic gases, such as 1) cooling of the gas from the exsolution temperature to the emission temperature at the surface, 2) pressure decrease from the depth of exsolution to atmospheric pressure, 3) composition of the gas and therefore ligand availability, 4) transport rate and its effect on mineral deposition from the gas.

How to cite: Mandon, C. and Stefansson, A.: Trace element transport processes in volcanic gases, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15216, https://doi.org/10.5194/egusphere-egu23-15216, 2023.

X2.138
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EGU23-15716
Edmond Grigoryan, Khachatur Meliksetian, Hripsime Gevorgyan, Ivan Savov, Gevorg Navasardyan, Marina Bangoyan, and Tatevik Boyakhchyan

Widespread volcanism played significant role in geological history of Anatolian-Armenian-Iranian orogenic plateau formed as a result of continental collision of Arabian and Eurasia. Among diverse chemical compositions and eruption styles, reported for volcanoes of Armenian highlands, noteworthy are distal tephra fallout deposits and voluminous ignimbrite shields resulted from violent explosive volcanic eruptions with VEI estimations ranging form 4 to 6. Obviously, such eruptions had significant impact on climate, human occupation and migrations in the entire region and provide insights to volcanic hazards in the region.  One difficulty in the identifying and studying explosive eruptions during Pleistocene, is that many tephra fallout deposits are not preserved in the geologic records, since unconsolidated deposits erode rapidly, particularly in mountain topography. In Armenia, there is a sparse geologic record of tephra fallouts, except where these deposits are preserved beneath pyroclastic flows, which presumably occurred very soon after tephra deposition. Such tephra deposits, are known in Armenia in underlying ignimbrite units related to activity of Aragats stratovolcano (Gevorgyan et al., 2018), beneath Ani ignimbrite in western part of Armenia and activity of Irind and Pemzashen volcanoes. Alternatively, tephra deposits can be preserved if layers are rapidly covered by loess deposits or colluvium deposits or landslides shortly after the eruption and tephra deposition occurs. Such conditions are known for distal tephra fall deposits from Ararat volcano in Ararat depression and in NE Armenia near Ijevan. A big number of finds of  Paleolithic stone tools, and resent achievements in studying Paleolithic archeology in south Caucasus region provide evidences of early human occupation in the territory of south Caucasus.  This contribution  aims to fill gaps in our knowledge of distal tephra layers identified in Armenia, namely in  north-east, south and central parts of Armenia.  New data based on detailed geochemical investigations and 40Ar/39Ar age determinations of distal tephra layers originated from violent explosive eruptions, reported in this study, can contribute to establish chronostratigraphic horizons as marker layers for paleoclimate and archaeological records during Middle-Upper Pleistocene in the entire region. Tephra layers preserved in Pleistocene sedimentary sequences in Armenia provide important information about these violent explosive eruptions that are significant for the geological evolution and the human geography of the entire region.

How to cite: Grigoryan, E., Meliksetian, K., Gevorgyan, H., Savov, I., Navasardyan, G., Bangoyan, M., and Boyakhchyan, T.: Tephrochronology and geochemical correlation of Middle Pleistocene distal tephra deposits in Armenia, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15716, https://doi.org/10.5194/egusphere-egu23-15716, 2023.

X2.139
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EGU23-7516
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ECS
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Niklas Karbach, Bastien Geil, Jonas Blumenroth, Heiko Bozem, Christian von Glahn, Peter Hoor, Nicole Bobrowski, and Thorsten Hoffmann

To protect people and infrastructures in the immediate vicinity of active volcanoes, monitoring the gas composition of the emitted plume is crucial. In order to react quickly to sudden changes in this composition, frequent measurements are key, as different ratios like the halogen/sulfur or the CO2/SO2 ratio can give hints on changing volcanic activity due to their different solubility in magma.   

However, monitoring the chemical composition of the volcanic plume is not an easy task, especially since stationary ground-based gas monitoring stations do not always measure the concentration in the plume, only under certain meteorological conditions, and remote sensing methods are not available for all gases of interest. In this case, human interaction is required to move the measurement equipment to the location of interest, which is close to the active vent. Not only does this pose a serious health risk, it is also burdensome, as the researcher must climb the volcano, take the measurements, climb back down, and analyze the results. This lengthy procedure can be sped up and facilitated by using lightweight drones to take the measurements. Sensors and various other instruments, such as miniaturized alkaline traps or impregnated syringe filters that employ an electrophilic addition to a double bond to selectively absorb halogen species in the oxidation states -1, ±0 and +1, can be mounted on the drone and controlled via a radio link to a ground station. The online results can then be used during the flight to locate the plume to ensure efficient sampling with the absorbers. The landing site of the drone is usually located far away from active vents, which significantly reduces health hazards and speeds up the process.

This poster presents such a drone with its advanced sensor system and absorbers for the determination and quantification of CO2, SO2, acidic gases and halogen species and its deployment during a measurement campaign on Etna in July 2022.

How to cite: Karbach, N., Geil, B., Blumenroth, J., Bozem, H., von Glahn, C., Hoor, P., Bobrowski, N., and Hoffmann, T.: Rapid gas measurements in volcanic plumes with UAVs: online and offline measurements of various trace gases with light UAVs, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7516, https://doi.org/10.5194/egusphere-egu23-7516, 2023.

X2.140
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EGU23-8281
Pasquale Sellitto, Giuseppe Salerno, Stefano Corradini, Irène Xueref-Remy, Aurélie Riandet, Clémence Bellon, Sergey Khaykin, Gerard Ancellet, Simone Lilli, Ellsworth J. Welton, Antonella Boselli, Alessia Sannino, Juan Cuesta, Henda Guermazi, Maxim Eremenko, Luca Merucci, Dario Stelitano, Lorenzo Guerrieri, and Bernard Legras

During the extended activity of Mount Etna volcano in February-April 2021, three distinct paroxysmal events took place from 21 to 26 February, which were associated with a very uncommon transport of the injected upper-tropospheric plumes towards the north. A major Saharan dust outbreak to central Europe occurred in the same period. Using a synergy of observations and modelling, we characterise the three-dimensional dispersion of these volcanic plumes and we disentangle their optical and radiative signature from the simultaneous Saharan dust transport. In the region of interest for our study, the volcanic and the dust plumes remain completely vertically-separated, thus facilitating the detection and spatiotemporal characterisation of the dispersion, properties and radiative impacts of these two different aerosol plumes, using vertically-resolved observations. With a satellite-based source inversion, we estimate the emitted sulphur dioxide (SO2) mass at an integrated value of 55 kt and plumes injections at up to 12 km altitudes, which qualifies this series as an extreme event for Mount Etna activity spectrum. Then, we combine Lagrangian dispersion modelling, initialised with measured temporally-resolved SO2 emission fluxes and altitudes, with satellite observations to track the dispersion of the individual volcanic and dust plumes. The general transport towards the north allowed the height-resolved downwind monitoring of the volcanic and dust plumes at selected observatories in France, Italy and Israel, using LiDARs and photometric aerosol observations. A specific effort has been dedicated to the characterisation of the volcanic aerosol plumes. Volcanic-specific aerosol optical depths in the visible spectral range ranging from about 0.004 to 0.03 and local daily average shortwave radiative forcing ranging from about -0.2 to -1.2 W/m2 (at the top of atmosphere) and from about -0.2 to -3.0 W/m2 (at the surface) are found. The composition (possible presence of ash), aerosol optical depth and radiative forcing of the volcanic plumes has a large inter- and intra-plume variability and thus depend strongly on the position of the sampled section of the plumes. The dust optical depth and radiative impact largely outweigh volcanic aerosols when the two plumes are co-located, for this event. This case study points at the complexity of the Mediterranean aerosol environment and pave the way to future studies at longer timescales, exploiting the available observational and modelling capabilities and their synergies.

How to cite: Sellitto, P., Salerno, G., Corradini, S., Xueref-Remy, I., Riandet, A., Bellon, C., Khaykin, S., Ancellet, G., Lilli, S., Welton, E. J., Boselli, A., Sannino, A., Cuesta, J., Guermazi, H., Eremenko, M., Merucci, L., Stelitano, D., Guerrieri, L., and Legras, B.: A case study of two simultaneous extreme aerosol events in the Mediterranean: The Mount Etna series of eruptions and major Saharan dust event in February 2021, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8281, https://doi.org/10.5194/egusphere-egu23-8281, 2023.