Small-scale volcanic aerosols variability, processes and direct radiative impact at Mount Etna during the EPL-RADIO campaigns

Abstract The aerosol properties of Mount Etna’s passive degassing plume and its short-term processes and radiative impact were studied in detail during the EPL-RADIO campaigns (summer 2016–2017), using a synergistic combination of observations and radiative transfer modelling. Summit observations show extremely high particulate matter concentrations. Using portable photometers, the first mapping of small-scale (within $$\sim 20\,\hbox {km}$$ ∼ 20 km from the degassing craters) spatial variability of the average size and coarse-to-fine burden proportion of volcanic aerosols is obtained. A substantial variability of the plume properties is found at these spatial scales, revealing that processes (e.g. new particle formation and/or coarse aerosols sedimentation) are at play, which are not represented with current regional scale modelling and satellite observations. Statistically significant progressively smaller particles and decreasing coarse-to-fine particles burden proportion are found along plume dispersion. Vertical structures of typical passive degassing plumes are also obtained using observations from a fixed LiDAR station constrained with quasi-simultaneous photometric observations. These observations are used as input to radiative transfer calculations, to obtain the shortwave top of the atmosphere (TOA) and surface radiative effect of the plume. For a plume with an ultraviolet aerosol optical depth of 0.12–0.14, daily average radiative forcings of $$-\;4.5$$ - 4.5 and $$-\;7.0\,\hbox {W/m}^2$$ - 7.0 W/m 2 , at TOA and surface, are found at a fixed location $$\sim 7\,\hbox {km}$$ ∼ 7 km downwind the degassing craters. This is the first available estimation in the literature of the local radiative impact of a passive degassing volcanic plume.

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Small-scale volcanic aerosols variability, processes and direct radiative impact at Mount Etna during the EPL-RADIO/REFLECT campaigns

10.5194/egusphere-egu2020-8337 ◽

2020 ◽

Author(s):

Pasquale Sellitto ◽

Giuseppe Salerno ◽

Alessandro La Spina ◽

Tommaso Caltabiano ◽

Simona Scollo ◽

...

Keyword(s):

Radiative Transfer ◽

Spatial Scales ◽

Regional Scale ◽

Saharan Dust ◽

Mount Etna ◽

Small Scale ◽

Volcanic Plume ◽

So2 Emissions ◽

Radiative Impact ◽

Volcanic Aerosols

The aerosol properties of Mount Etna&#8217;s passive degassing plume and its short-term processes and radiative impact were studied in detail during the EPL-RADIO/REFLECT campaigns (summer 2016, 17 and 19), using a synergistic combination of remote-sensing and in situ observations, and radiative transfer modelling. Summit observations show extremely high particulate matter concentrations, with no evidence of secondary sulphate aerosols (SA) formation. Marked indications of secondary SA formation, i.e. by the conversion of volcanic SO2 emissions, are found at larger spatial scales (<20 km downwind craters). Using portable photometers, the first mapping of small-scale spatial variability of the average size and burden of volcanic aerosols is obtained, as well as different longitudinal, perpendicular and vertical sections. A substantial variability of the plume properties is found at these spatial scales, revealing that processes (e.g. new particle formation and coarse aerosols sedimentation) are at play, which are not represented with current regional scale modelling and satellite observations. Vertical structures of typical passive degassing plumes are also obtained using observations from a fixed LiDAR station constrained with quasi-simultaneous photometric observations. These observations are used as input to radiative transfer calculations, to obtain the shortwave top of the atmosphere (TOA) and surface radiative effects of the plume. Moreover, the radiative impact of Mount Etna&#8217;s emissions is studied using a medium-term time series (a few months during summer 2019) of coupled aerosol optical properties and surface radiative flux at a fixed station on Etna&#8217;s eastern flank. These are the first available estimations in the literature of the radiative impact of a passive degassing volcanic plume and are here critically discussed. Cases of co-existent volcanic aerosol layers and aerosols from other sources (Saharan dust transport events, wildfire from South Italy and marine aerosols) are also presented and discussed.

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The observation of different aerosols types in the Mount Etna environment and their relative and mutual impacts on local radiative balance

10.5194/egusphere-egu21-12380 ◽

2021 ◽

Author(s):

Pasquale Sellitto ◽

Giuseppe Salerno ◽

Simona Scollo ◽

Alcide Giorgio di Sarra ◽

Antonella Boselli ◽

...

Keyword(s):

Spatial Scales ◽

Source Parameters ◽

Mount Etna ◽

Volcanic Plume ◽

Dynamical Regime ◽

Radiative Balance ◽

Volcanic Aerosols ◽

Aerosol Types ◽

Lidar Observations

The EPL-RADIO (Etna Plume Lab - Radioactive Aerosols and other source parameters for better atmospheric Dispersion and Impact estimatiOns) and EPL-REFLECT (near-source estimations of Radiative EFfects of voLcanic aErosols for Climate and air quality sTudies) projects, funded by the EC Horizon2020 ENVRIplus and EUROVOLC Transnational Access to European Observatories programmes, aim to advance the understanding of Mount Etna as a persistent source of atmospheric aerosols and its impact on the&#160; radiative budget at proximal to regional spatial scales. Research was tackled by carrying out three campaigns in the summers of 2016, 2017 and 2019 to observe the volcanic plume produced by passive degassing, proximally and distally from the summit craters, using a wide array of remote sensing and in situ instruments. Diverse data are collected to explore the link of inner degassing mechanisms to the characterisation of near-source aerosol physicochemical properties and subsequent impacts on the atmosphere, environment and regional climate system.The results of the three campaigns have shown that the volcanic plume emitted by Mount Etna often mixes with aerosols of different origins generating a complex layered pattern. Frequent mineral dust transport events were observed by both LiDAR observations located at Serra La Nave (~7 km south-west from summit craters) and at a medium-term radiometric station, equipped with a Multi-Filter Rotating Shadowband Radiometer (MFRSR), and other instruments located at Milo (~10 km eastwards from the craters). LiDAR observations also allowed to study the coexistence of volcanic aerosols and biomass burning particles from local to more distal smoke plumes transports (like for the well-documented large fires from continental southern Italy in July 2017). In situ filter and optical particles counter measurements confirmed the presence of dust at Milo. The interaction/mixing among volcanic, wildfire, and dust aerosols occurs in an overall dynamical regime which appears to be dominated by sea breeze, which is strengthened by the presence of the dark volcanic lava flanks. Photolysis process also possibly play a role in determining the daily evolution of the aerosol plume.The sources of these different aerosol types are studied in detail using Lagrangian trajectories and meteorological data. Off-line radiative transfer calculations, using EPL-RADIO/REFLECT observations as input data, are used to estimate the relative radiative impact of the different aerosol types with respect to the background passive-degassing aerosols coming from Mount Etna.

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Impact of the Christmas 2018 Mount Etna Eruption on the Regional Air Quality

10.5194/egusphere-egu21-2167 ◽

2021 ◽

Author(s):

Claire Lamotte ◽

Jonathan Guth ◽

Virginie Marécal ◽

Giuseppe Salerno ◽

Nicolas Theys ◽

...

Keyword(s):

Air Quality ◽

Regional Scale ◽

Volcanic Eruptions ◽

Mount Etna ◽

Surface Measurement ◽

Volcanic Plume ◽

Observation Data ◽

Sulfate Aerosols ◽

Lower Altitude ◽

The Impact

Volcanic eruptions are events that can eject several tons of material into the atmosphere. Among these emissions, sulfur dioxide is the main sulfurous volcanic gas. It can form sulfate aerosols that are harmful to health or, being highly soluble, it can condense in water particles and form acid rain. Thus, volcanic eruptions can have an environmental impact on a regional scale.The Mediterranean region is very interesting from this point of view because it is a densely populated region with a strong anthropogenic activity, therefore polluted, in which Mount Etna is also located. Mount Etna is the largest passive SO2 emitter in Europe, but it can also sporadically produce strong eruptive events. It is then likely that the additional input of sulfur compounds into the atmosphere by volcanic emissions may have effects on the regional atmospheric sulfur composition.We are particularly investigating the eruption of Mount Etna on December 24, 2018 [Corradini et al, 2020]. This eruption took place along a 2 km long breach on the side of the volcano, thus at a lower altitude than its main crater. About 100 kt of SO2 and 35 kt of ash were released in total, between December 24 and 30. With the exception of the 24th, the quantities of ash were always lower than the SO2.The availability of the TROPOMI SO2column estimates, at fine spatial resolution (7 km x 3.5 km at nadir) and associated averaging kernels, during this eruptive period made it also an excellent case study. It allows us to follow the evolution of SO2 in the volcanic plume over several days.Using the CNRM MOCAGE chemistry-transport model (CTM), we aim to quantify the impact of this volcanic eruption on atmospheric composition, sulfur deposition and air quality at the regional scale. The comparison of the model with the TROPOMI observation data allows us to assess the ability of the model to properly represent the plume. In spite of a particular meteorological situation, leading to a complex plume transport, MOCAGE shows a good agreement with TROPOMI observations. Thus, from the MOCAGE simulation, we can evaluate the impact of the eruption on the regional concentrations of SO2 and sulfate aerosols, but also analyse the quantities of dry and wet deposition, and compare it to surface measurement stations.

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A Spectra Classification Methodology of Hyperspectral Infrared Images for Near Real-Time Estimation of the SO2 Emission Flux from Mount Etna with LARA Radiative Transfer Retrieval Model

Remote Sensing ◽

10.3390/rs12244107 ◽

2020 ◽

Vol 12 (24) ◽

pp. 4107

Author(s):

Charlotte Segonne ◽

Nathalie Huret ◽

Sébastien Payan ◽

Mathieu Gouhier ◽

Valéry Catoire

Keyword(s):

Radiative Transfer ◽

Real Time ◽

Mount Etna ◽

High Spectral Resolution ◽

Retrieval Algorithm ◽

Volcanic Plume ◽

Transfer Model ◽

So2 Emission ◽

North East ◽

Emission Fluxes

Fast and accurate quantification of gas fluxes emitted by volcanoes is essential for the risk mitigation of explosive eruption, and for the fundamental understanding of shallow eruptive processes. Sulphur dioxide (SO2), in particular, is a reliable indicator to predict upcoming eruptions, and its systemic characterization allows the rapid assessment of sudden changes in eruptive dynamics. In this regard, infrared (IR) hyperspectral imaging is a promising new technology for accurately measure SO2 fluxes day and night at a frame rate down to 1 image per second. The thermal infrared region is not very sensitive to particle scattering, which is an asset for the study of volcanic plume. A ground based infrared hyperspectral imager was deployed during the IMAGETNA campaign in 2015 and provided high spectral resolution images of the Mount Etna (Sicily, Italy) plume from the North East Crater (NEC), mainly. The LongWave InfraRed (LWIR) hyperspectral imager, hereafter name Hyper-Cam, ranges between 850–1300 cm−1 (7.7–11.8 µm). The LATMOS (Laboratoire Atmosphères Milieux Observations Spatiales) Atmospheric Retrieval Algorithm (LARA), which is used to retrieve the slant column densities (SCD) of SO2, is a robust and a complete radiative transfer model, well adapted to the inversion of ground-based remote measurements. However, the calculation time to process the raw data and retrieve the infrared spectra, which is about seven days for the retrieval of one image of SO2 SCD, remains too high to infer near real-time (NRT) SO2 emission fluxes. A spectral image classification methodology based on two parameters extracting spectral features in the O3 and SO2 emission bands was developed to create a library. The relevance is evaluated in detail through tests. From data acquisition to the generation of SO2 SCD images, this method requires only ~40 s per image, which opens the possibility to infer NRT estimation of SO2 emission fluxes from IR hyperspectral imager measurements.

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Using the 3D MOCAGE CTM to simulate the chemistry of halogens in the volcanic plume of Etna's eruption in December 2018 at the regional scale

10.5194/egusphere-egu21-12205 ◽

2021 ◽

Author(s):

Herizo Narivelo ◽

Virginie Marécal ◽

Paul David Hamer ◽

Luke Surl ◽

Tjarda Roberts ◽

...

Keyword(s):

Remote Sensing ◽

Transport Model ◽

Regional Scale ◽

Mount Etna ◽

Volcanic Plume ◽

Gaseous Species ◽

Modelling Studies ◽

Order Of Magnitude ◽

The Impact ◽

Halogen Species

Volcanoes emit different gaseous species, SO&#8322; and in particular halogen species especially bromine and chlorine compounds. In general, halogens play an important role in the atmosphere by contributing to ozone depletion in the stratosphere (WMO Ozone assessment, 2018) and by modifying air composition and oxidizing capacity in the troposphere (Von Glasow et al. 2004). The halogen species emitted by volcanoes are halides. The chemical processing occurring within the plume leads to the formation of BrO from HBr following the &#8216;bromine explosion&#8217; mechanism as evidenced from both observations and modelling (e.g., Bobrowski et al. Nature, 2003; Roberts et al., Chem. Geol. 2009). Oxidized forms of chlorine and bromine are modelled to be formed within the plume due to the heterogenous reaction of HOBr with HCl and HBr, forming BrCl and Br&#8322; that photolyses and produces Br and Cl radicals. So far, modelling studies were mainly focused on the very local scale and processes occurring within a few hours after eruption.In this study, the objective is to go a step further by analyzing the impact at the regional scale over the Mediterranean basin of a Mt Etna eruption event. For this, we use the MOCAGE model (Guth et al., GMD, 2016), a chemistry transport model run with a resolution of 0.2&#176;x 0.2&#176;, to quantify the impacts of the halogens species emitted by the volcano on the tropospheric composition. We have selected here the case of the eruption of Mount Etna around Christmas 2018 characterised by large amounts of emissions over several days (Calvari et al., remote sensing 2020; Corrdadini et al., remote sensing 2020). The results show that MOCAGE represents rather well the chemistry of the halogens in the volcanic plume because it established theory of plume chemistry. The bromine explosion process takes place on the first day of the eruption and even more strongly the day after, with a rapid increase of the in-plume BrO concentrations and a corresponding strong&#160;reduction of ozone and NO2&#160;concentrations.We also compared MOCAGE results with the WRF-CHEM model simulations for the same case study. We note that the tropospheric column of BrO and SO&#8322; in the two models have the same order of magnitude with more rapid bromine explosion occurring in WRF-CHEM simulations. Finally, we compared the MOCAGE results to tropospheric columns of BrO and SO2 retrieved from TROPOMI spaceborne instrument.

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Emergent Behavior and Uncertainty in Multimodel Climate Projections of Precipitation Trends at Small Spatial Scales

Journal of Climate ◽

10.1175/jcli3932.1 ◽

2006 ◽

Vol 19 (21) ◽

pp. 5554-5569 ◽

Cited By ~ 9

Author(s):

P. Good ◽

J. Lowe

Keyword(s):

Large Scale ◽

Climate Models ◽

Scale Effects ◽

Spatial Scales ◽

Regional Scale ◽

Emergent Behavior ◽

Small Scale ◽

Climate Projections ◽

New Methods ◽

Precipitation Trends

Abstract Aspects of model emergent behavior and uncertainty in regional- and small-scale effects of increasing CO2 on seasonal (June–August) precipitation are explored. Nineteen different climate models are studied. New methods of comparing multiple climate models reveal a clearer and more impact-relevant view of precipitation projections for the current century. First, the importance of small spatial scales in multimodel projections is demonstrated. Local trends can be much larger than or even have an opposing sign to the large-scale regional averages used in previous studies. Small-scale effects of increasing CO2 and natural internal variability both play important roles here. These small-scale features make multimodel comparisons difficult for precipitation. New methods that allow information from small spatial scales to be usefully compared across an ensemble of multiple models are presented. The analysis philosophy of this study works with statistical distributions of small-scale variations within climatological regions. A major result of this work is a set of emergent relationships coupling the small- and regional-scale effects of CO2 on precipitation trends. Within each region, a single relationship fits the ensemble of 19 different climate models. Using these relationships, a surprisingly large part of the intermodel variance in small-scale effects of CO2 is explainable simply by the intermodel variance in the regional mean (a form of pattern scaling). Different regions show distinctly different relationships. These relationships imply that regional mean results are still useful, as long as the interregional variation in their relationship with impact-relevant extreme trends is recognized. These relationships are used to present a clear but rich picture of an aspect of model uncertainty, characterized by the intermodel spread in seasonal precipitation trends, including information from small spatial scales.

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No outbreeding depression at a regional scale for a habitat-forming intertidal alga with limited dispersal

Marine and Freshwater Research ◽

10.1071/mf05078 ◽

2006 ◽

Vol 57 (6) ◽

pp. 655 ◽

Cited By ~ 8

Author(s):

P. F. McKenzie ◽

Alecia Bellgrove

Keyword(s):

Gene Flow ◽

Early Development ◽

Large Scale ◽

Spatial Scales ◽

Regional Scale ◽

Subsequent Development ◽

Small Scale ◽

Outbreeding Depression ◽

Fertilisation Success ◽

Limited Dispersal

Hormosira banksii is distributed throughout southern Australasia, but dispersal of propagules is thought to be limited. In the present study, the hypothesis that outbreeding depression occurs in H. banksii was tested by assessing fertilisation success and early development of embryos in crosses between populations at local to regional spatial scales. Hierarchical experiments were conducted at three spatial scales with nesting present within each scale: small scale (within a rocky shore population), intermediate scale (regions separated by 70 km) and large scale (450-km separation between two states: Victoria and Tasmania). In each experiment, eggs and sperm were crossed within and between each population located in the spatial scale of interest. There were no consistent patterns of variable fertilisation success and subsequent development within a population or at different spatial scales. It was concluded that outbreeding depression is not detected in analyses of fertilisation success or early development processes in H. banksii. The results suggest one of the following to be likely: (1) H. banksii is capable of longer distance dispersal than previously considered, thus maintaining gene flow between distant populations, (2) gene flow is restricted by limited dispersal, but populations have not been isolated for a sufficient length of time to cause genetic divergence or (3) outbreeding depression is manifested as effects on later life-history stages.

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Präzisions-Forstwirtschaft – was ist das? | Precision forestry – what's that?

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2007.0235 ◽

2007 ◽

Vol 158 (8) ◽

pp. 235-242 ◽

Cited By ~ 2

Author(s):

Hans Rudolf Heinimann

Keyword(s):

Business Processes ◽

Spatial Scales ◽

Supply Chain Coordination ◽

Sensor Technology ◽

Small Scale ◽

Soil Physics ◽

Coordination Problem ◽

Precision Engineering ◽

Precision Forestry ◽

And Control

The term «precision forestry» was first introduced and discussed at a conference in 2001. The aims of this paper are to explore the scientific roots of the precision concept, define «precision forestry», and sketch the challenges that the implementation of this new concept may present to practitioners, educators, and researchers. The term «precision» does not mean accuracy on a small scale, but instead refers to the concurrent coordination and control of processes at spatial scales between 1 m and 100 km. Precision strives for an automatic control of processes. Precision land use differs from precision engineering by the requirements of gathering,storing and managing spatio-temporal variability of site and vegetation parameters. Practitioners will be facing the challenge of designing holistic, standardized business processes that are valid for whole networks of firms,and that follow available standards (e.g., SCOR, WoodX). There is a need to educate and train forestry professionals in the areas of business process re-engineering, computer supported management of business transactions,methods of remote sensing, sensor technology and control theory. Researchers will face the challenge of integrating plant physiology, soil physics and production sciences and solving the supply chain coordination problem (SCCP).

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Performance Analysis of the Rotating Biological Contactor Process Based on Particle Fraction and Improvement of Final Effluent Quality

Water Science & Technology ◽

10.2166/wst.1991.0598 ◽

1991 ◽

Vol 23 (7-9) ◽

pp. 1457-1466 ◽

Cited By ~ 3

Author(s):

Kazuhiro Tanaka ◽

Minoru Tada ◽

Mitsuo Ito ◽

Noritugu Shimizu

Keyword(s):

Suspended Solids ◽

Fine Particles ◽

Wastewater Treatment Plants ◽

Small Scale ◽

Particle Fraction ◽

Effluent Quality ◽

Rotating Biological Contactors ◽

Activated Sludge Processes ◽

Fraction Method ◽

Final Effluent

Biofilm processes are, in general, suitable for small-scale wastewater treatment plants. However, final effluent qualities of biofilm processes are not as good as those of activated sludge processes due to fine particles remaining in the effluents. To improve the effluent qualities of the Rotating Biological Contactors (RBC) process, the behavior of fine particles through the process and the removal of fine particles with solids-liquid separation methods, rapid filtration and coagulation-filtration, were investigated using the particle fraction method. The results are as follows:–An increase of the hydraulic retention time (HRT) in the RBC reactor reduced the amount of fine particles and increased the amount of coarse suspended solids of 44 µm or more in diameter, which are easily removed by clarification. Thus, the final effluent qualities were improved by the increase of HRT.–Suspended solids in effluent from the RBC process at the standard loading are so fine that improvement of the quality is not expected by only lowering the overflow rate of a final clarifier. In contrast, rapid filtration or a coagulation-filtration process is effective. The supended solid concentration and transparency of the effluent from the final clarifier was improved by a factor of two to four, and then BOD of the final effluent was removed by 40-85%.

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Dispersal and Land Cover Contribute to Pseudorabies Virus Exposure in Invasive Wild Pigs

EcoHealth ◽

10.1007/s10393-020-01508-6 ◽

2021 ◽

Author(s):

Felipe A. Hernández ◽

Amanda N. Carr ◽

Michael P. Milleson ◽

Hunter R. Merrill ◽

Michael L. Avery ◽

...

Keyword(s):

Land Cover ◽

Disease Transmission ◽

Wildlife Conservation ◽

Pseudorabies Virus ◽

Spatial Scales ◽

Information Criterion ◽

Small Scale ◽

Wild Pigs ◽

Bacterial Agent ◽

Open Canopy

AbstractWe investigated the landscape epidemiology of a globally distributed mammal, the wild pig (Sus scrofa), in Florida (U.S.), where it is considered an invasive species and reservoir to pathogens that impact the health of people, domestic animals, and wildlife. Specifically, we tested the hypothesis that two commonly cited factors in disease transmission, connectivity among populations and abundant resources, would increase the likelihood of exposure to both pseudorabies virus (PrV) and Brucella spp. (bacterial agent of brucellosis) in wild pigs across the Kissimmee Valley of Florida. Using DNA from 348 wild pigs and sera from 320 individuals at 24 sites, we employed population genetic techniques to infer individual dispersal, and an Akaike information criterion framework to compare candidate logistic regression models that incorporated both dispersal and land cover composition. Our findings suggested that recent dispersal conferred higher odds of exposure to PrV, but not Brucella spp., among wild pigs throughout the Kissimmee Valley region. Odds of exposure also increased in association with agriculture and open canopy pine, prairie, and scrub habitats, likely because of highly localized resources within those land cover types. Because the effect of open canopy on PrV exposure reversed when agricultural cover was available, we suggest that small-scale resource distribution may be more important than overall resource abundance. Our results underscore the importance of studying and managing disease dynamics through multiple processes and spatial scales, particularly for non-native pathogens that threaten wildlife conservation, economy, and public health.

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