Experimental simulations of volcanic ash resuspension by wind under the effects of atmospheric humidity

Bello, E. Del; Taddeucci, Jacopo; Merrison, J.; Alois, Stefano; Iversen, J.; Scarlato, Piergiorgio

doi:10.1038/s41598-018-32807-2

Cited by 22 publications

(17 citation statements)

References 38 publications

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“…Regarding moisture content, material from Iceland can be suspended under moister atmospheric conditions (>70% relative humidity) than what is measured in other major dust sources of the world (for example those reported in Csavina et al (2014)). This finding coincides with laboratory studies done with volcanic ash from Eyjafjallajökull where suspension of grains was able to occur at all humidity levels (Del Bello et al, 2018).…”

Section: Discussionsupporting

confidence: 91%

Influence of Weather Conditions on Particulate Matter Suspension following the 2010 Eyjafjallajökull Volcanic Eruption

et al. 2020

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The 2010 eruption of Eyjafjallajökull produced volcanic ash that was mostly deposited to the south and east of the volcano with the thickest deposits closest to the eruption vents. For months following the eruption there were numerous reports of resuspended volcanic ash made by weather observers on the ground. A saltation sensor (SENSIT) and an Optical Particle Counter (OPC) located on the southern side of Eyjafjallajökull measured post-eruptive particulate matter (PM) saltation and suspension events, some of which were also observable by satellite imagery. During the fall/winter following the eruption visible satellite images and the SENSIT show that PM measured by the OPC were only detected by the when winds had a northerly component, making the source on the slopes of Eyjafjallajökull. During the largest observed events, particles >10 μm were suspended but measured in extremely low concentrations (< 1 particle/cm3). The saltation measurements, however, show high concentrations of particles >100 μm in size during these events. During the largest events, winds were at least 5 ms-1 with a relative humidity < 70%. Ground conditions in Iceland change quickly from unfavorable to favorable for the suspension of particles. It is hypothesized that this is due to the porosity of the surface material allowing water to filter through quickly, as well as the fast-drying time of surface material. The high moisture content of the atmosphere and the ground do not appear to be a deterrent for large PM events to occur in Iceland.

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Section: Discussionsupporting

confidence: 91%

Influence of Weather Conditions on Particulate Matter Suspension following the 2010 Eyjafjallajökull Volcanic Eruption

et al. 2020

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“…Del Bello et al () reported on a series of laboratory‐based measurements of u *t for ash samples from the Campi Flegrei region of Italy and Eyjafjallajökull in Iceland. They found that u *t was sensitive to RH, especially when RH was higher than 90% and when the particles considered were smaller than 63 μm (obtained by sieving).…”

Section: Introductionmentioning

confidence: 99%

Laboratory Experiments of Volcanic Ash Resuspension by Wind

et al. 2019

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Fresh volcanic eruption deposits tend to be loose, bare, and readily resuspended by wind. Major resuspension events in Patagonia, Iceland, and Alaska have lofted ash clouds with potential to impact aircraft, infrastructure, and downwind communities. However, poor constraints on this resuspension process limit our ability to model this phenomenon. Here, we present laboratory experiments measuring threshold shear velocities and emission rates of resuspended ash under different environmental conditions, including relative humidity of 25–75% and simulated rainfall with subsequent drying. Eruption deposits were replicated using ash collected from two major eruptions: the 18 May 1980 eruption of Mount St. Helens and the 1912 eruption of Novarupta, in Alaska's Valley of Ten Thousand Smokes. Samples were conditioned in a laboratory chamber and prepared with bulk deposit densities of 1,300–1,500 kg/m3. A control sample of dune sand was included for comparison. The deposits were subjected to different wind speeds using a modified PI‐SWERL® instrument. Under a constant relative humidity of 50% and shear velocities 0.4–0.8 m/s, PM10 emission by resuspension ranged from 10 to >100 mg·m−2·s−1. Addition of liquid water equivalent to 5 mm of rainfall had little lasting effect on Mount St. Helens wind erosion potential, while the Valley of Ten Thousand Smokes deposits exhibited lower emissions for at least 12 days. The results indicate that particle resuspension due to wind erosion from ash deposits potentially exceeds that of most desert surfaces and approaches some of the highest emissions ever measured.

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“…The applicability of traditional dust emission schemes to ash resuspension should be further investigated. In particular, future studies should aim at developing and validating specific emission schemes for volcanic ash based on recent experimental studies for ash resuspension [24,25]. In this work, emission flux was computed using a semi-empirical dust emission scheme based on the parameterisation proposed by Shao et al [51,52].…”

Section: Emission Schemementioning

confidence: 99%

“…Similarly, wind tunnel experiments carried out by Fowler and Lopushinsky [23] showed that freshly deposited ash can be resuspended at relatively low wind speeds, while consolidation of tephra-fallout deposits resulting from successive cycles of wetting and drying processes, caused a significant increase in the threshold wind velocity of erosion (i.e., the minimum wind speed required to mobilise the soil particles) [9]. More recently, Del Bello et al [24] conducted wind tunnel experiments under controlled ambient humidity conditions, highlighting that resuspension of smaller particles is hindered at high humidity levels. In parallel, Etyemezian et al [25] measured also emission rates and erosion thresholds in a humidity-controlled chamber using a small wind tunnel-like device.…”

Section: Introductionmentioning

confidence: 99%

Volcanic Ash Resuspension in Patagonia: Numerical Simulations and Observations

et al. 2020

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Resuspension of pyroclastic deposits occurs under specific atmospheric and environmental conditions and typically prolongs and exacerbates the impact associated with the primary emplacement of tephra fallout and pyroclastic density current deposits. An accurate forecasting of the phenomenon, to support Volcanic Ash Advisory Centers (VAACs) and civil aviation management, depends on adapting volcanic ash transport and dispersion models to include specific ash emission schemes. Few studies have attempted to model the mechanisms of emission and transport of windblown volcanic ash, and a systematic study of observed cases has not been carried out yet. This manuscript combines numerical simulations along with a variety of observational data to examine the general features of ash resuspension events in northern Patagonia following the 2011 Cordón Caulle eruption (Chile). The associated outcomes provide new insights into the spatial distribution of sources, frequency of events, transport patterns, seasonal and diurnal variability, and spatio-temporal distribution of airborne ash. A novel modelling approach based on the coupling between Advanced Research core of the Weather Research and Forecasting (WRF-ARW) and FALL3D models is presented, with various model improvements that allow overcoming some limitations in previous ash resuspension studies. Outcomes show the importance of integrating source information based on field measurements (e.g., deposit grain size distribution and particle density). We provide evidence of a strong diurnal and seasonal variability associated with the ash resuspension activity in Patagonia. According to the modelled emission fluxes, ash resuspension activity was found to be significantly more intense during daytime hours. Satellite observations and numerical simulations strongly suggest that major emission sources of resuspended ash were distributed across distal areas (>100 km from the vent) of the Patagonian steppe, covered by a thin layer of fine ash. The importance of realistic soil moisture data to properly model the spatial distribution of emission sources is also highlighted.

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Experimental simulations of volcanic ash resuspension by wind under the effects of atmospheric humidity

Cited by 22 publications

References 38 publications

Influence of Weather Conditions on Particulate Matter Suspension following the 2010 Eyjafjallajökull Volcanic Eruption

Influence of Weather Conditions on Particulate Matter Suspension following the 2010 Eyjafjallajökull Volcanic Eruption

Laboratory Experiments of Volcanic Ash Resuspension by Wind

Volcanic Ash Resuspension in Patagonia: Numerical Simulations and Observations

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