Document Type
Article
Publication Date
4-10-1996
Abstract
Dielectric data in volcanic ash at weather radar wavelengths (centimeter range) are extremely sparse and are crucial for radar sensing of ash clouds and for imaging of volcanic terrains. This study extends previous data to include a wavelength range of 1.5–7.5 cm and volcanic ash compositions of 50–75% silica. The real part of the complex permittivity, ε′, of volcanic ash is 6 ± 0.5 (1σ) for all wavelengths. The imaginary part, ε″, ranges from 0.08 to 0.27. Both ε′ and ε″ show higher values at lower SiO2 concentration. It is safe to assume in any weather radar applications that the reflectivity factor is K = |(ε − 1)/(ε + 2)|2 = 0.39 ± 0.02 (1σ), regardless of composition or wavelength. The results will help quantify radar observations of volcanic clouds.
Publication Title
Journal of Geophysical Research
Recommended Citation
Adams, R. J.,
Perger, W. F.,
Rose, W. I.,
&
Kostinski, A.
(1996).
Measurements of the complex dielectric constant of volcanic ash from 4 to 19 GHz.
Journal of Geophysical Research,
101(B4), 8175-8185.
http://doi.org/10.1029/96JB00193
Retrieved from: https://digitalcommons.mtu.edu/geo-fp/85
Version
Publisher's PDF
Publisher's Statement
Copyright 1996 by the American Geophysical Union. Publisher's version of record: https://dx.doi.org/10.1029/96JB00193