Modeling volcanic ash resuspension – application to the 14–18 October 2011 outbreak episode in central Patagonia, Argentina

Folch, Arnau; Mingari, Leonardo; Osores, María Soledad; Collini, Estela Ángela

doi:10.5194/nhess-14-119-2014

Cited by 45 publications

(52 citation statements)

References 33 publications

(59 reference statements)

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“…On the other hand, airborne volcanic ash was distributed evenly across the area surrounding the volcano, seen as an average increase in the SPM concentrations. Considering that fine volcanic ash can stay airborne for extended periods and that unconsolidated light ash can be recirculated (Folch et al, 2014), this would indicate that once released from the volcano, fine ash emissions are caught within localised circulations and diffused across the surrounding area, increasing the associated health hazards (Lähde et al, 2013). This is also reflected in the ashfall deposition values, as a background value of ∼ 1-10 g m −2 mo −1 was also seen independently of the season and dominant wind patterns.…”

Section: Discussionmentioning

confidence: 99%

Statistical analysis of dispersal and deposition patterns of volcanic emissions from Mt. Sakurajima, Japan

Poulidis

Takemi

Shimizu

et al. 2018

Atmospheric Environment

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A B S T R A C TWith the eruption of Eyjafjallajökull (Iceland) in 2010, interest in the transport of volcanic ash after moderate to major eruptions has increased with regards to both the physical and the emergency hazard management aspects. However, there remain significant gaps in the understanding of the long-term behaviour of emissions from volcanoes with long periods of activity. Mt. Sakurajima (Japan) provides us with a rare opportunity to study such activity, due to its eruptive behaviour and dense observation network. In the 6-year period from 2009 to 2015, the volcano was erupting at an almost constant rate introducing approximately 500 kt of ash per month to the atmosphere. The long-term characteristics of the transport and deposition of ash and SO 2 in the area surrounding the volcano are studied here using daily surface observations of suspended particulate matter (SPM) and SO 2 and monthly ashfall values.Results reveal different dispersal patterns for SO 2 and volcanic ash, suggesting volcanic emissions' separation in the long-term. Peak SO 2 concentrations at different locations on the volcano vary up to 2 orders of magnitude and decrease steeply with distance. Airborne volcanic ash increases SPM concentrations uniformly across the area surrounding the volcano, with distance from the vent having a secondary effect. During the period studied here, the influence of volcanic emissions was identifiable both in SO 2 and SPM concentrations which were, at times, over the recommended exposure limits defined by the Japanese government, European Union and the World Health Organisation.Depositional patterns of volcanic ash exhibit elements of seasonality, consistent with previous studies. Climatological and topographic effects are suspected to impact the deposition of volcanic ash away from the vent: for sampling stations located close to complex topographical elements, sharp changes in the deposition patterns were observed, with ash deposits for neighbouring stations as close as 5 km differing as much as an order of magnitude. Despite these effects, deposition was sufficiently approximated by an inverse power law relationship, the fidelity of which depended on the distance from the vent: for proximal to intermediate areas (20 km), errors decrease with longer accumulation periods (tested here for 1-72 months), while the opposite was seen for deposition in distal areas (>20 km).

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Section: Discussionmentioning

confidence: 99%

Statistical analysis of dispersal and deposition patterns of volcanic emissions from Mt. Sakurajima, Japan

Poulidis

Takemi

Shimizu

et al. 2018

Atmospheric Environment

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“…The Fall3D model in resuspension mode (Folch et al, 2014) includes three different emission schemes (of increasing sophistication) that are applied to the case of volcanic ash, although they have been developed theoretically or calibrated experimentally for mineral dust: (i) Westphal scheme (Westphal et al, 1987), (ii) Marticorena and Bergametti scheme (Marticorena and Bergametti, 1995;Marticorena et al, 1997), and (iii) Shao scheme (Shao et al, 1993;Shao and Leslie, 1997;Shao and Lu, 2000).…”

Section: Dust Emission Schemementioning

confidence: 99%

“…In this work, we use the Shao scheme as is described by Folch et al (2014) with minor modifications. The theory for dust emission by Shao et al (1993) is based on a hypothesis about the energetics of dust emission and considers particle-particle interaction by saltation bombardment (see Folch et al, 2014, for more details).…”

Section: Dust Emission Schemementioning

confidence: 99%

“…The theory for dust emission by Shao et al (1993) is based on a hypothesis about the energetics of dust emission and considers particle-particle interaction by saltation bombardment (see Folch et al, 2014, for more details). This parametrization depends crucially on deposit characteristics such as particle size distribution, thickness, and particle density and requires reliable input data.…”

Section: Dust Emission Schemementioning

confidence: 99%

“…However, studies focused on the performance of dispersion models simulating concentrations of windblown dust in South America are scarce (e.g., Johnson et al, 2010;Gaiero et al, 2013). For example, events of volcanic ash resuspension in Patagonia were recently simulated using the WRF-ARW/FALL3D modeling system with promising results (Folch et al, 2014;Reckziegel et al, 2016). Dust models simulate the main processes of the dust cycle: emission, transport, and deposition (Tegen, 2003).…”

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Numerical simulations of windblown dust over complex terrain: the Fiambalá Basin episode in June 2015

et al. 2017

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Abstract. On 13 June 2015, the London Volcanic Ash Advisory Centre (VAAC) warned the Buenos Aires VAAC about a possible volcanic eruption from the Nevados Ojos del Salado volcano (6879 m), located in the Andes mountain range on the border between Chile and Argentina. A volcanic ash cloud was detected by the SEVIRI instrument on board the Meteosat Second Generation (MSG) satellites from 14:00 UTC on 13 June.In this paper, we provide the first comprehensive description of this event through observations and numerical simulations. Our results support the hypothesis that the phenomenon was caused by wind remobilization of ancient pyroclastic deposits (ca. 4.5 ka Cerro Blanco eruption) from the Bolsón de Fiambalá (Fiambalá Basin) in northwestern Argentina. We have investigated the spatiotemporal distribution of aerosols and the emission process over complex terrain to gain insight into the key role played by the orography and the condition that triggered the long-range transport episode.Numerical simulations of windblown dust were performed using the ARW (Advanced Research WRF) core of the WRF (Weather Research and Forecasting) model (WRF-ARW) and FALL3D modeling system with meteorological fields downscaled to a spatial resolution of 2 km in order to resolve the complex orography of the area. Results indicate that favorable conditions to generate dust uplifting occurred in northern Fiambalá Basin, where orographic effects caused strong surface winds. According to short-range numerical simulations, dust particles were confined to near-ground layers around the emission areas. In contrast, dust aerosols were injected up to 5-6 km high in central and southern regions of the Fiambalá Basin, where intense ascending airflows are driven by horizontal convergence.Long-range transport numerical simulations were also performed to model the dust cloud spreading over northern Argentina. Results of simulated vertical particle column mass were compared with the MSG-SEVIRI retrieval product. We tested two numerical schemes: with the default configuration of the FALL3D model, we found difficulties to simulate transport through orographic barriers, whereas an alternative configuration, using a numerical scheme to more accurately compute the horizontal advection in abrupt terrains, substantially improved the model performance.

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Ash mists and brown snow: Remobilization of volcanic ash from recent Icelandic eruptions

et al. 2014

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Recent eruptions in Iceland and Chile have demonstrated that volcanic ash problems persist long after an eruption. For this reason, ash dispersion models are being extended to include ash remobilization. Critical to these models is knowledge of the ash source and the particle sizes that can be mobilized under different wind and moisture conditions. Here we characterize the physical and chemical characteristics of ash deposited on new snow in Reykjavík, Iceland, following a blizzard on 6 March 2013. Morphological, textural, and compositional analyses indicate resuspension from multiple eruptive deposits, including both Grímsvötn (2011) and Eyjafjallajökull (2010) eruptions. Grain size measurements show a mode of 32-63 μm, with particles as large as 177 μm; there is little mass in the very fine fraction, ≤10 μm (PM 10 ). We compare our observations to predictions using the Lagrangian particle dispersion model, NAME (UK Met Office). The model output is consistent with observations in that it forecasts resuspension from both Eyjafjallajökull and Grímsvötn source regions, and shows ash deposition coincident with the timing of observed deposition in Reykjavík. The modeled deposit in Reykjavík predicts, however, a substantially lower proportion of Grímsvötn ash than observed. This discrepancy has highlighted the need to reassess the assumptions used in the simulations, particularly regarding the source area and precipitation thresholds. Furthermore, we suggest that modification of ash deposits in the form of erosion, redeposition, compaction, or cementation may influence the dynamics of resuspension over time, thus influencing the ability of model simulations to accurately forecast remobilization events.

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Modeling volcanic ash resuspension – application to the 14–18 October 2011 outbreak episode in central Patagonia, Argentina

Cited by 45 publications

References 33 publications

Statistical analysis of dispersal and deposition patterns of volcanic emissions from Mt. Sakurajima, Japan

Statistical analysis of dispersal and deposition patterns of volcanic emissions from Mt. Sakurajima, Japan

Numerical simulations of windblown dust over complex terrain: the Fiambalá Basin episode in June 2015

Ash mists and brown snow: Remobilization of volcanic ash from recent Icelandic eruptions

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