scholarly journals Volcanic SO<sub>2</sub> Layer Height by TROPOMI/S5P; validation against IASI/MetOp and CALIOP/CALIPSO observations

2021 ◽  
Author(s):  
Maria-Elissavet Koukouli ◽  
Konstantinos Michailidis ◽  
Pascal Hedelt ◽  
Isabelle A. Taylor ◽  
Antje Inness ◽  
...  
Keyword(s):  
Real Time ◽  
Traffic Safety ◽  
European Space Agency ◽  
Volcanic Eruptions ◽  
Mean Difference ◽  
Atmospheric Composition ◽  
Retrieval Algorithm ◽  
Volcanic Plume ◽  
Layer Height ◽  
The Impact

Abstract. Volcanic eruptions eject large amounts of ash and trace gases such as sulphur dioxide (SO2) into the atmosphere. A significant difficulty in mitigating the impact of volcanic SO2 clouds on air traffic safety is that these gas emissions can be rapidly transported over long distances. The use of space-borne instruments enables the global monitoring of volcanic SO2 emissions in an economical and risk-free manner. Within the European Space Agency (ESA) Sentinel-5p+ Innovation project, the S5P SO2 Layer Height (S5P+I: SO2 LH) activities led to the improvements on the retrieval algorithm and generation of the corresponding near-real-time S5P SO2 LH products. These are currently operationally provided, in near-real-time, by the German Aerospace Center (DLR) in the framework of the Innovative Products for Analyses of Atmospheric Composition, INPULS, project. The main aim of this paper is to present its extensive verification, accomplished within the S5P+I: SO2 LH project, over major recent volcanic eruptions, against collocated space-born measurements from the IASI/Metop and CALIOP/CALIPSO instruments, as well as assess its impact on the forecasts provided by the Copernicus Atmospheric Monitoring Service, CAMS. The mean difference between S5P and IASI observations for the Raikoke 2019, the Nishinoshima 2020 and the La Soufrière-St Vincent, 2021 eruptive periods is ~0.5 ± 3 km, while for the Taal 2020 eruption, a larger difference was found, between 3 and 4 ± 3 km. The comparison of the daily mean SO2 layer heights further demonstrates the capabilities of this near-real-time product, with slopes between 0.8 and 1 and correlations ranging between 0.6 and 0.8. Comparisons between the S5P+I: SO2 LH and the CALIOP/CALIPSO ash plume height are also satisfactory at −2.5 ± 2 km, considering that the injected SO2 and ash plumes’ locations do not always coincide over an eruption. Furthermore, the CAMS assimilation of the S5P+I: SO2 LH product led to much improved model output against the non-assimilated IASI layer heights, with a mean difference of 1.5 ± 2 km compared to the original CAMS analysis, and improved the geographical spread of the Raikoke volcanic plume following the eruptive days.

scholarly journals Probabilistic retrieval of volcanic SO<sub>2</sub> layer height and partial column density using the Cross-track Infrared Sounder (CrIS)

2020 ◽  
Vol 13 (11) ◽  
pp. 5891-5921
Author(s):  
David M. Hyman ◽  
Michael J. Pavolonis
Keyword(s):  
Real Time ◽  
Column Density ◽  
Probabilistic Approach ◽  
Volcanic Eruptions ◽  
Volcanic Plume ◽  
Retrieval Method ◽  
Layer Height ◽  
Wide Range ◽  
The Cross ◽  
Cross Track

Abstract. During most volcanic eruptions and many periods of volcanic unrest, detectable quantities of sulfur dioxide (SO2) are injected into the atmosphere at a wide range of altitudes, from ground level to the lower stratosphere. Because the fine ash fraction of a volcanic plume is, at times, colocated with SO2 emissions, global tracking of volcanic SO2 is useful in tracking the hazard long after ash detection becomes dominated by noise. Typically, retrievals of SO2 vertical column density (VCD) have relied heavily on hyperspectral ultraviolet measurements. More recently, infrared sounders have provided additional VCD measurements and estimates of the SO2 layer altitude, adding significant value to real-time monitoring of volcanic emissions and climatological analyses. These methods can provide fast and accurate physics-based retrievals of VCD and altitude without regard to solar irradiance, meaning that they are effective day and night and can observe high-latitude SO2 even in the winter. In this study, we detail a probabilistic enhancement of an infrared SO2 retrieval method, based on a modified trace gas retrieval, to estimate SO2 VCD and altitude probabilistically using the Cross-track Infrared Sounder (CrIS) on the Joint Polar Satellite System (JPSS) series of satellites. The methodology requires the characterization of real SO2-free spectra aggregated seasonally and spatially. The probabilistic approach replaces altitude and VCD estimates with probability density functions for the layer height and the partial VCD at multiple heights, fully quantifying the retrieval uncertainty and allowing the estimation of SO2 partitioning by layer. This framework adds significant value over basic VCD and altitude retrieval because it can be used to assign probabilities of SO2 occurrence to different atmospheric intervals. We highlight analyses of several recent significant eruptions, including the 22 June 2019 eruption of Raikoke volcano, in the Kuril Islands; the mid-December 2016 eruption of Bogoslof volcano, in the Aleutian Islands; and the 26 June 2018 eruption of Sierra Negra volcano, in the Galapagos Islands. This retrieval method is currently being implemented in the VOLcanic Cloud Analysis Toolkit (VOLCAT), where it will be used to generate additional cloud object properties for real-time detection, probabilistic characterization, and tracking of volcanic clouds in support of aviation safety.

scholarly journals SO<sub>2</sub> Layer Height retrieval from Sentinel-5 Precursor/TROPOMI using FP_ILM

2019 ◽  
Author(s):  
Pascal Hedelt ◽  
Dmitry S. Efremenko ◽  
Diego G. Loyola ◽  
Robert Spurr ◽  
Lieven Clarisse
Keyword(s):  
Accurate Determination ◽  
Volcanic Eruptions ◽  
Critical Parameters ◽  
Retrieval Algorithm ◽  
Layer Height ◽  
Precise Knowledge ◽  
Learning Machine ◽  
The Impact ◽  
First Time

Abstract. Precise knowledge of the location and height of the volcanic SO2 plumes is essential for accurate determination of SO2 emitted by volcanic eruptions for aviation control applications, but so far very time-consuming to retrieve from UV satellite data. The SO2 height is furthermore one of the most critical parameters that determine the impact on the climate. We have developed an extremely fast yet accurate SO2 layer height retrieval algorithm using the Full-Physics Inverse Learning Machine (FP_ILM) algorithm, which, for the first time, is applied to TROPOMI aboard Sentinel-5 Precursor. In this work we demonstrate the ability of the FP_ILM algorithm to retrieve layer heights in near-real time applications with an accuracy of better than 2 km for SO2 total columns larger than 20 DU and show SO2 layer height results for selected volcanic eruptions.

Revisiting the Krakatau 1883 Volcanic Aerosol Dispersal 

2021 ◽  
Author(s):  
Rafael Castro ◽  
Tushar Mittal ◽  
Stephen Self
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Volcanic Eruptions ◽  
Climate Impact ◽  
Volcanic Plume ◽  
Quasi Biennial Oscillation ◽  
Aerosol Cloud ◽  
Pinatubo Eruption ◽  
The Impact

&lt;p&gt;The 1883 Krakatau eruption is one of the most well-known historical volcanic eruptions due to its significant global climate impact as well as first recorded observations of various aerosol associated optical and physical phenomena. Although much work has been done on the former by comparison of global climate model predictions/ simulations with instrumental and proxy climate records, the latter has surprisingly not been studied in similar detail. In particular, there is a wealth of observations of vivid red sunsets, blue suns, and other similar features, that can be used to analyze the spatio-temporal dispersal of volcanic aerosols in summer to winter 1883. Thus, aerosol cloud dispersal after the Krakatau eruption can be estimated, bolstered by aerosol cloud behavior as monitored by satellite-based instrument observations after the 1991 Pinatubo eruption. This is one of a handful of large historic eruptions where this analysis can be done (using non-climate proxy methods). In this study, we model particle trajectories of the Krakatau eruption cloud using the Hysplit trajectory model and compare our results with our compiled observational dataset (principally using Verbeek 1884, the Royal Society report, and Kiessling 1884).&lt;/p&gt;&lt;p&gt;In particular, we explore the effect of different atmospheric states - the quasi-biennial oscillation (QBO) which impacts zonal movement of the stratospheric volcanic plume - to estimate the phase of the QBO in 1883 required for a fast-moving westward cloud. Since this alone is unable to match the observed latitudinal spread of the aerosols, we then explore the impact of an&amp;#160; umbrella cloud (2000 km diameter) that almost certainly formed during such a large eruption. A large umbrella cloud, spreading over ~18 degrees within the duration of the climax of the eruption (6-8 hours), can lead to much quicker latitudinal spread than a point source (vent). We will discuss the results of the combined model (umbrella cloud and correct QBO phase) with historical accounts and observations, as well as previous work on the 1991 Pinatubo eruption. We also consider the likely impacts of water on aerosol concentrations and the relevance of this process for eruptions with possible significant seawater interactions, like Krakatau. We posit that the role of umbrella clouds is an under-appreciated, but significant, process for beginning to model the climatic impacts of large volcanic eruptions.&lt;/p&gt;

Investigation of volcanic emissions in Antikythera PANGEA station using near-real-time alerts

2021 ◽  
Author(s):  
Anna Kampouri ◽  
Vassilis Amiridis ◽  
Stavros Solomos ◽  
Anna Gialitaki ◽  
Eleni Marinou ◽  
...  
Keyword(s):  
Real Time ◽  
Dispersion Model ◽  
Atmospheric Composition ◽  
Dust Particles ◽  
Volcanic Plume ◽  
Observation Data ◽  
National Observatory ◽  
Development Fund ◽  
Model Simulations ◽  
Geophysical Observatory

&lt;p&gt;In the last years, several Etna eruption events are documented, forming lava flows and explosive activity. The Pilot EO4D_ash &amp;#8211; Earth observation data for detection, discrimination &amp; distribution (4D) of volcanic ash of the e-shape project provides the PANhellenic GEophysical observatory of Antikythera (PANGEA) of the National Observatory of Athens (NOA), in Greece with near-real-time alerts from Etna volcano eruptions. These alerts are used in the PANGEA station to monitor and reveal the presence of volcanic particles above the area the days following an eruption, also the station is supported by a volcanic particle monitoring and forecasting warning system. In this work, we investigate the volcano eruption between 30 May and 6 June 2019 which affected the southern parts of Greece and reaching the Antikythera station. Due to the prevailing meteorological conditions, volcanic particles and gases followed an easterly direction and were dispersed towards Greece. FLEXPART dispersion model simulations confirm the volcanic plume transport from Etna towards PANGEA, mixing also with co-existing desert dust particles. Model simulations are evaluated with Polly&lt;sup&gt;XT&lt;/sup&gt; lidar measurements performed at PANGEA and satellite-based SO&lt;sub&gt;2&lt;/sub&gt; observations from the TROPOspheric Monitoring Instrument onboard the Sentinel-5 Precursor (TROPOMI/S5P). This is the first time that Etna volcanic products are monitored at the Antikythera station, in Greece with implications for the investigation of their role in the Mediterranean weather and climate.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Acknowledgments&lt;/strong&gt;: We acknowledge the support by EU H2020 E-shape project (Grant Agreement n. 820852). Also, this research was supported by data and services obtained from the PANhellenic Geophysical Observatory of Antikythera (PANGEA) of the National Observatory of Athens (NOA), Greece, and by the project &amp;#8220;PANhellenic infrastructure for Atmospheric Composition and climatE change&amp;#8221; (MIS 5021516) which is implemented under the Action &amp;#8220;Reinforcement of the Research and Innovation Infrastructure&amp;#8221;, funded by the Operational Programme &quot;Competitiveness, Entrepreneurship and Innovation&quot; (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund). NOA team acknowledges the support of the Stavros Niarchos Foundation (SNF).&lt;/p&gt;

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

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

&lt;p&gt;&lt;span&gt;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.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;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 SO&lt;sub&gt;2&lt;/sub&gt; 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.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;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 SO&lt;sub&gt;2&lt;/sub&gt; 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 SO&lt;sub&gt;2.&lt;/sub&gt;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;The availability of the TROPOMI SO&lt;sub&gt;2&lt;/sub&gt;&lt;sub&gt;&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;column &lt;/span&gt;&lt;span&gt;estimates, at fine &lt;/span&gt;&lt;span&gt;spatial&lt;/span&gt;&lt;span&gt; resolution &lt;/span&gt;&lt;span&gt;(7 km x 3.5 km at nadir) and &lt;/span&gt;&lt;span&gt;associated averaging kernels&lt;/span&gt;&lt;span&gt;,&lt;/span&gt;&lt;span&gt; during this eruptive period made it also an excellent case study. &lt;/span&gt;&lt;span&gt;It &lt;/span&gt;&lt;span&gt;allow&lt;/span&gt;&lt;span&gt;s&lt;/span&gt;&lt;span&gt; us to follow the evolution of SO&lt;sub&gt;2&lt;/sub&gt; in the volcanic plume over several days.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;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 SO&lt;sub&gt;2&lt;/sub&gt; and sulfate aerosols, but also analyse the quantities of dry and wet deposition, and compare it to surface measurement stations.&lt;/span&gt;&lt;/p&gt;

scholarly journals Sulfur dioxide layer height retrieval from Sentinel-5 Precursor/TROPOMI using FP_ILM

2019 ◽  
Vol 12 (10) ◽  
pp. 5503-5517 ◽  
Author(s):  
Pascal Hedelt ◽  
Dmitry S. Efremenko ◽  
Diego G. Loyola ◽  
Robert Spurr ◽  
Lieven Clarisse
Keyword(s):  
Sulfur Dioxide ◽  
Accurate Determination ◽  
Volcanic Eruptions ◽  
Critical Parameters ◽  
Layer Height ◽  
Learning Machine ◽  
The Impact ◽  
First Time ◽  
Better Than

Abstract. The accurate determination of the location, height, and loading of sulfur dioxide (SO2) plumes emitted by volcanic eruptions is essential for aviation safety. The SO2 layer height is also one of the most critical parameters with respect to determining the impact on the climate. Retrievals of SO2 plume height have been carried out using satellite UV backscatter measurements, but, until now, such algorithms are very time-consuming. We have developed an extremely fast yet accurate SO2 layer height retrieval using the Full-Physics Inverse Learning Machine (FP_ILM) algorithm. This is the first time the algorithm has been applied to measurements from the TROPOMI instrument onboard the Sentinel-5 Precursor platform. In this paper, we demonstrate the ability of the FP_ILM algorithm to retrieve SO2 plume layer heights in near-real-time applications with an accuracy of better than 2 km for SO2 total columns larger than 20 DU. We present SO2 layer height results for the volcanic eruptions of Sinabung in February 2018, Sierra Negra in June 2018, and Raikoke in June 2019, observed by TROPOMI.

scholarly journals The impact of MISR-derived injection height initialization on wildfire and volcanic plume dispersion in the HYSPLIT model

2018 ◽  
Vol 11 (11) ◽  
pp. 6289-6307 ◽  
Author(s):  
Charles J. Vernon ◽  
Ryan Bolt ◽  
Timothy Canty ◽  
Ralph A. Kahn
Keyword(s):  
Volcanic Eruptions ◽  
Dust Storms ◽  
Volcanic Plume ◽  
Plume Dispersion ◽  
Hysplit Model ◽  
Particle Injection ◽  
Nominal Model ◽  
Satellite Retrievals ◽  
Aerosol Sources ◽  
The Impact

Abstract. The dispersion of particles from wildfires, volcanic eruptions, dust storms, and other aerosol sources can affect many environmental factors downwind, including air quality. Aerosol injection height is one source attribute that mediates downwind dispersion, as wind speed and direction can vary dramatically with elevation. Using plume heights derived from space-based, multi-angle imaging, we examine the impact of initializing plumes in the NOAA Air Resources Laboratory's Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model with satellite-measured vs. nominal (model-calculated or VAAC-reported) injection height on the simulated dispersion of six large aerosol plumes. When there are significant differences in nominal vs. satellite-derived particle injection heights, especially if both heights are in the free troposphere or if one injection height is within the planetary boundary layer (PBL) and the other is above the PBL, differences in simulation results can arise. In the cases studied with significant nominal vs. satellite-derived injection height differences, the HYSPLIT model can represent plume evolution better, relative to independent satellite observations, if the injection height in the model is constrained by hyper-stereo satellite retrievals.

scholarly journals 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

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.

Extremely fast retrieval of volcanic SO2 layer heights from UV satellite data using inverse learning machines

2021 ◽  
Author(s):  
Pascal Hedelt ◽  
MariLiza Koukouli ◽  
Konstantinos Michaelidis ◽  
Taylor Isabelle ◽  
Dimitris Balis ◽  
...  
Keyword(s):  
Real Time ◽  
Accurate Determination ◽  
Principal Component ◽  
Volcanic Eruptions ◽  
Neural Network Approach ◽  
Layer Height ◽  
Precise Knowledge ◽  
Innovation Project ◽  
Learning Machine

&lt;p&gt;Precise knowledge of the location and height of the volcanic sulfur dioxide (SO&lt;sub&gt;2&lt;/sub&gt;) plume is essential for accurate determination of SO&lt;sub&gt;2&lt;/sub&gt; emitted by volcanic eruptions, however so far not available in operational near-real time UV satellite retrievals. The FP_ILM algorithm (Full-Physics Inverse Learning Machine) enables for the first time to extract the SO&lt;sub&gt;2&lt;/sub&gt; layer height information in a matter of seconds for current UV satellites and is thus applicable in NRT environments.&lt;/p&gt;&lt;p&gt;The FP_ILM combines a principal component analysis (PCA) and a neural network approach (NN) to extract the information about the volcanic SO&lt;sub&gt;2&lt;/sub&gt; layer height from high-resolution UV satellite backscatter measurements. So far, UV based SO&lt;sub&gt;2 &lt;/sub&gt;layer height retrieval algorithms were very time-consuming and therefore not suitable for near-real-time applications like aviation control, although the SO&lt;sub&gt;2&lt;/sub&gt; LH is essential for accurate determination of SO&lt;sub&gt;2&lt;/sub&gt; emitted by volcanic eruptions.&lt;/p&gt;&lt;p&gt;In this presentation, we will present the latest FP_ILM algorithm improvements and show results of recent volcanic eruptions.&lt;/p&gt;&lt;p&gt;The SO&lt;sub&gt;2&lt;/sub&gt; layer height product for Sentinel-5p/TROPOMI is developed in the framework of the SO&lt;sub&gt;2&lt;/sub&gt;&amp;#160;Layer Height (S5P+I: SO&lt;sub&gt;2&lt;/sub&gt; LH)&amp;#160;project, which is part of ESA Sentinel-5p+ Innovation project (S5P+I). The S5P+I project aims to develop novel scientific and operational products to exploit the potential of the S5P/TROPOMI capabilities. The S5P+I: SO&lt;sub&gt;2&lt;/sub&gt; LH&amp;#160;project is dedicated to the generation of an SO&lt;sub&gt;2&lt;/sub&gt;&amp;#160;LH product and its extensive verification with collocated ground- and space-born measurements.&lt;/p&gt;

Dispersion Model Evaluation for the Sulfur Dioxide Plume from the 2019 Raikoke Eruption using Satellite Measurements.

2020 ◽  
Author(s):  
Johannes de Leeuw ◽  
Anja Schmidt ◽  
Claire Witham ◽  
Nicolas Theys ◽  
Richard Pope ◽  
...  
Keyword(s):  
Sulfur Dioxide ◽  
Dispersion Model ◽  
European Space Agency ◽  
Volcanic Eruptions ◽  
Numerical Dispersion ◽  
Aviation Industry ◽  
Volcanic Plume ◽  
Satellite Measurements ◽  
Volcanic Gas ◽  
Vertical Column

&lt;p&gt;Volcanic eruptions pose a serious threat to the aviation industry causing widespread disruption. To identify any potential impacts, nine Volcanic Ash Advisory Centres (VAACs) provide global monitoring of all eruptions, informing stakeholders how each volcanic eruption might interfere with aviation. Numerical dispersion models represent a vital infrastructure when assessing and forecasting the atmospheric conditions from a volcanic plume.&lt;/p&gt;&lt;p&gt;In this study we investigate the 2019 Raikoke eruption, which emitted approximately 1.5 Tg of sulfur dioxide (SO&lt;sub&gt;2&lt;/sub&gt;) representing the largest volcanic emission of SO&lt;sub&gt;2&lt;/sub&gt; into the stratosphere since the Nabro eruption in 2011. Using the UK Met Office&amp;#8217;s Numerical Atmospheric-dispersion Modelling Environment (NAME), we simulate the evolution of the volcanic gas and aerosol particle plumes (SO&lt;sub&gt;2&lt;/sub&gt; and sulfate, SO&lt;sub&gt;4&lt;/sub&gt;) across the Northern Hemisphere between 21&lt;sup&gt;st&lt;/sup&gt; June and 17&lt;sup&gt;th &lt;/sup&gt;July. We evaluate the skills and limitations of NAME in terms of modelling volcanic SO&lt;sub&gt;2 &lt;/sub&gt;plumes, by comparing our simulations to high-resolution measurements from the Tropospheric Monitoring Instrument (TROPOMI) on-board the European Space Agency (ESA)&amp;#8217;s Sentinel 5 &amp;#8211; Precursor (S5P) satellite.&lt;/p&gt;&lt;p&gt;Our comparisons show that NAME accurately simulates the observed location and shape of the SO&lt;sub&gt;2&lt;/sub&gt; plume in the first few weeks after the eruption. NAME also reproduces the magnitude of the observed SO&lt;sub&gt;2 &lt;/sub&gt;vertical column densities, when emitting 1.5 Tg of SO&lt;sub&gt;2&lt;/sub&gt;, during the first 48 hours after the eruption. On longer timescales, we find that the model-simulated SO&lt;sub&gt;2 &lt;/sub&gt;plume in NAME is more diffuse than in the TROPOMI measurements, resulting in an underestimation of the peak SO&lt;sub&gt;2&lt;/sub&gt; vertical column densities in the model. This suggests that the diffusion parameters used in NAME are too large in the upper troposphere and lower stratosphere.&lt;/p&gt;&lt;p&gt;Finally, NAME underestimates the total mass of SO&lt;sub&gt;2&lt;/sub&gt; when compared to estimates from TROPOMI, however emitting 2 Tg of SO&lt;sub&gt;2&lt;/sub&gt; in the model improves the comparison, resulting in very good agreement with the satellite measurements.&lt;/p&gt;

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