Reference data set of volcanic ash physicochemical and optical properties

Author(s): A. Vogel, S. Diplas, A. J. Durant, A. S. Azar, M. F. Sunding, W. I. Rose, A. Sytchkova, C. Bonadonna, K. Krüger, A. Stohl
Abstract: Uncertainty in the physicochemical and optical properties of volcanic ash particles creates errors in the detection and modeling of volcanic ash clouds and in quantification of their potential impacts. In this study, we provide a data set that describes the physicochemical and optical properties of a representative selection of volcanic ash samples from nine different volcanic eruptions covering a wide range of silica contents (50–80 wt % SiO₂). We measured and calculated parameters describing the physical (size distribution, complex shape, and dense-rock equivalent mass density), chemical (bulk and surface composition), and optical (complex refractive index from ultraviolet to near-infrared wavelengths) properties of the volcanic ash and classified the samples according to their SiO₂ and total alkali contents into the common igneous rock types basalt to rhyolite. We found that the mass density ranges between ρ = 2.49 and 2.98 g/cm³ for rhyolitic to basaltic ash types and that the particle shape varies with changing particle size (d < 100 μm). The complex refractive indices in the wavelength range between λ = 300 nm and 1500 nm depend systematically on the composition of the samples. The real part values vary from n = 1.38 to 1.66 depending on ash type and wavelength and the imaginary part values from k = 0.00027 to 0.00268. We place our results into the context of existing data and thus provide a comprehensive data set that can be used for future and historic eruptions, when only basic information about the magma type producing the ash is known.
Organisation(s): Department of Meteorology and Geophysics
External organisation(s): Norwegian Institute for Air Research, University of Oslo, SINTEF The Foundation for Scientific and Industrial Research at the Norwegian Institute of Technology (NTH), Michigan Technological University, Université de Genève, Italian National Agency for New Technologies, Energy and Sustainable Economic Development
Journal: Journal of Geophysical Research: Atmospheres
Volume: 122
Pages: 9485-9514
No. of pages: 30
ISSN: 2169-897X
DOI: https://doi.org/10.1002/2016JD026328
Publication date: 09-2017
Peer reviewed: Yes
Austrian Fields of Science 2012: 105206 Meteorology
Keywords
ASJC Scopus subject areas: Geophysics, Atmospheric Science, Space and Planetary Science, Earth and Planetary Sciences (miscellaneous)
Portal url: https://ucrisportal.univie.ac.at/en/publications/dd7758ce-e9bf-4d76-ad84-f104b6f913ce

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