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Characteristics of Particle Size Distributions of Falling Volcanic Ash Measured by Optical Disdrometers at the Sakurajima Volcano, Japan.

Authors :
Maki, Masayuki
Takaoka, Ren
Iguchi, Masato
Zidikheri, Meelis
Hoffman, Lars
Source :
Atmosphere. May2021, Vol. 12 Issue 5, p601. 1p.
Publication Year :
2021

Abstract

In the present study, we analyzed the particle size distribution (PSD) of falling volcanic ash particles measured using optical disdrometers during six explosive eruptions of the Sakurajima volcano in Kagoshima Prefecture, Japan. Assuming the gamma PSD model, which is commonly used in radar meteorology, we examined the relationships between each of the gamma PSD parameters (the intercept parameter, the slope parameter, and the shape parameter) calculated by the complete moment method. It was shown that there were good correlations between each of the gamma PSD parameters, which might be one of the characteristics of falling volcanic ash particles. We found from the normalized gamma PSD analysis that the normalized intercept parameter and mass-weighted mean diameter are suitable for estimating the ash fall rate. We also derived empirical power law relationships between pairs of integrated PSD parameters: the ash fall rate, the volcanic ash mass concentration, the reflectivity factor, and the total number of ash particles per unit volume. The results of the present study provide essential information for studying microphysical processes in volcanic ash clouds, developing a method for quantitative ash fall estimation using weather radar, and improving ash transport and sedimentation models. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
20734433
Volume :
12
Issue :
5
Database :
Academic Search Index
Journal :
Atmosphere
Publication Type :
Academic Journal
Accession number :
150475153
Full Text :
https://doi.org/10.3390/atmos12050601