Sensitivity of Volcanic Ash Dispersion Modelling to Input Grain Size Distribution Based on Hydromagmatic and Magmatic Deposits
The size distribution of volcanic ash is rarely measured in real time and Volcanic Ash Advisory Centres (VAACs) often rely on a default particle size distribution (PSD) to initialise their dispersion models when forecasting the movement of ash clouds. We conducted a sensitivity study to investigate...
Published in: | Atmosphere |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
MDPI AG
2020
|
Subjects: | |
Online Access: | https://doi.org/10.3390/atmos11060567 https://doaj.org/article/88115aab2491421e8562075d1f926240 |
id |
ftdoajarticles:oai:doaj.org/article:88115aab2491421e8562075d1f926240 |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:88115aab2491421e8562075d1f926240 2023-05-15T16:09:37+02:00 Sensitivity of Volcanic Ash Dispersion Modelling to Input Grain Size Distribution Based on Hydromagmatic and Magmatic Deposits Sara Osman Frances Beckett Alison Rust Eveanjelene Snee 2020-05-01T00:00:00Z https://doi.org/10.3390/atmos11060567 https://doaj.org/article/88115aab2491421e8562075d1f926240 EN eng MDPI AG https://www.mdpi.com/2073-4433/11/6/567 https://doaj.org/toc/2073-4433 doi:10.3390/atmos11060567 2073-4433 https://doaj.org/article/88115aab2491421e8562075d1f926240 Atmosphere, Vol 11, Iss 567, p 567 (2020) volcanic ash particle size distributions total grain size distributions dispersion modelling Meteorology. Climatology QC851-999 article 2020 ftdoajarticles https://doi.org/10.3390/atmos11060567 2022-12-31T01:29:15Z The size distribution of volcanic ash is rarely measured in real time and Volcanic Ash Advisory Centres (VAACs) often rely on a default particle size distribution (PSD) to initialise their dispersion models when forecasting the movement of ash clouds. We conducted a sensitivity study to investigate the impact of PSD on model output and consider how best to apply default PSDs in operational dispersion modelling. Compiled grain size data confirm that, when considering particles likely to be in the distal ash cloud (< 125 µm diameter), magma composition and eruption size are the dominant controls on grain size distribution. Constraining the PSD is challenging but we find that the grain size of deposits from large hydromagmatic eruptions remains relatively constant with distance, suggesting that total (whole-deposit) grain size distributions (TGSDs) for these eruptions could be estimated from a few samples. We investigated the sensitivity of modelled ash mass loadings (in the air and on the ground) to input PSDs based on coarse to fine TGSDs from our dataset. We found clear differences between modelled mass loadings and the extent of the plume. Comparing TGSDs based on ground-only and ground-plus-satellite data for the Eyjafjallajökull 2010 eruption, we found that basing input PSDs on TGSDs from deposits alone (likely missing the finest particles) led to lower modelled peak ash concentrations and a smaller plume. Article in Journal/Newspaper Eyjafjallajökull Directory of Open Access Journals: DOAJ Articles Atmosphere 11 6 567 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
volcanic ash particle size distributions total grain size distributions dispersion modelling Meteorology. Climatology QC851-999 |
spellingShingle |
volcanic ash particle size distributions total grain size distributions dispersion modelling Meteorology. Climatology QC851-999 Sara Osman Frances Beckett Alison Rust Eveanjelene Snee Sensitivity of Volcanic Ash Dispersion Modelling to Input Grain Size Distribution Based on Hydromagmatic and Magmatic Deposits |
topic_facet |
volcanic ash particle size distributions total grain size distributions dispersion modelling Meteorology. Climatology QC851-999 |
description |
The size distribution of volcanic ash is rarely measured in real time and Volcanic Ash Advisory Centres (VAACs) often rely on a default particle size distribution (PSD) to initialise their dispersion models when forecasting the movement of ash clouds. We conducted a sensitivity study to investigate the impact of PSD on model output and consider how best to apply default PSDs in operational dispersion modelling. Compiled grain size data confirm that, when considering particles likely to be in the distal ash cloud (< 125 µm diameter), magma composition and eruption size are the dominant controls on grain size distribution. Constraining the PSD is challenging but we find that the grain size of deposits from large hydromagmatic eruptions remains relatively constant with distance, suggesting that total (whole-deposit) grain size distributions (TGSDs) for these eruptions could be estimated from a few samples. We investigated the sensitivity of modelled ash mass loadings (in the air and on the ground) to input PSDs based on coarse to fine TGSDs from our dataset. We found clear differences between modelled mass loadings and the extent of the plume. Comparing TGSDs based on ground-only and ground-plus-satellite data for the Eyjafjallajökull 2010 eruption, we found that basing input PSDs on TGSDs from deposits alone (likely missing the finest particles) led to lower modelled peak ash concentrations and a smaller plume. |
format |
Article in Journal/Newspaper |
author |
Sara Osman Frances Beckett Alison Rust Eveanjelene Snee |
author_facet |
Sara Osman Frances Beckett Alison Rust Eveanjelene Snee |
author_sort |
Sara Osman |
title |
Sensitivity of Volcanic Ash Dispersion Modelling to Input Grain Size Distribution Based on Hydromagmatic and Magmatic Deposits |
title_short |
Sensitivity of Volcanic Ash Dispersion Modelling to Input Grain Size Distribution Based on Hydromagmatic and Magmatic Deposits |
title_full |
Sensitivity of Volcanic Ash Dispersion Modelling to Input Grain Size Distribution Based on Hydromagmatic and Magmatic Deposits |
title_fullStr |
Sensitivity of Volcanic Ash Dispersion Modelling to Input Grain Size Distribution Based on Hydromagmatic and Magmatic Deposits |
title_full_unstemmed |
Sensitivity of Volcanic Ash Dispersion Modelling to Input Grain Size Distribution Based on Hydromagmatic and Magmatic Deposits |
title_sort |
sensitivity of volcanic ash dispersion modelling to input grain size distribution based on hydromagmatic and magmatic deposits |
publisher |
MDPI AG |
publishDate |
2020 |
url |
https://doi.org/10.3390/atmos11060567 https://doaj.org/article/88115aab2491421e8562075d1f926240 |
genre |
Eyjafjallajökull |
genre_facet |
Eyjafjallajökull |
op_source |
Atmosphere, Vol 11, Iss 567, p 567 (2020) |
op_relation |
https://www.mdpi.com/2073-4433/11/6/567 https://doaj.org/toc/2073-4433 doi:10.3390/atmos11060567 2073-4433 https://doaj.org/article/88115aab2491421e8562075d1f926240 |
op_doi |
https://doi.org/10.3390/atmos11060567 |
container_title |
Atmosphere |
container_volume |
11 |
container_issue |
6 |
container_start_page |
567 |
_version_ |
1766405472500318208 |