Light scattering from volcanic-sand particles in deposited and aerosol form

DOI: 
10.1016/j.atmosenv.2019.06.051
Publication date: 
18/09/2019
Main author: 
Zubko N.
IAA authors: 
Muñoz, O.
Authors: 
Zubko N., Muñoz O., Zubko E., Gritsevich M., Escobar-Cerezo J., Berg M.J., Peltoniemi J.
Journal: 
Atmospheric Environment
Refereed: 
Yes
Publication type: 
Article
Volume: 
215.0
Pages: 
116813
Number: 
116813
Abstract: 
The light-scattering properties of volcanic sand collected in Iceland are studied here to characterize the sand particles and develop a reference for future remote-sensing observations. While such sand is common in Iceland, the smaller-size fraction can be readily transported by winds and found in the atmosphere at distant locations. The sand appears dark when deposited on a surface due to the high optical absorption of the material. Therefore, atmospheric regions containing such particles during a dust storm may absorb sunlight considerably, causing redistribution of solar energy. Here, we measure the angular scattered-light intensity and degree of linear polarization from the sand. This is done with two experimental apparatuses, the Cosmic Dust Laboratory (CoDuLab) at the Institute de Astrofísica de Andalucía (IAA) and the goniospectropolarimeter (FIGIFIGO) at the Finnish Geospatial Research Institute (FGI). Two scattering-scenarios of practical interest for remote-sensing applications are considered: (1) single sand-particles suspended in aerosol as an optically thin cloud, and (2) the same particles deposited on a substrate. We also model the measurements with the discrete dipole approximation to estimate the complex-valued refractive index m, where we find that m ≈ 1.6 + 0.01i at λ = 647 nm. Lastly, we present a comparative analysis of the polarimetric response of the sand particles with that reported in the literature for carbon-soot, another highly absorbing atmospheric contaminant. © 2019
Database: 
SCOPUS
ADS
URL: 
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85071459229&doi=10.1016%2fj.atmosenv.2019.06.051&partnerID=40&md5=808cf9228398e234ce3d41619bbf87a0
ADS Bibcode: 
2019AtmEn.21516813Z
Keywords: 
Aerosols; Discrete dipole approximation; Light scattering; Particulate surface; Photometry; Polarimetry; Radiometry; Refractive index; Remote sensing; Soot; Volcanic sand