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Quantitative three‐dimensional ice roughness from scanning electron microscopy
Author(s) -
Butterfield Nicholas,
Rowe Penny M.,
Stewart Emily,
Roesel David,
Neshyba Steven
Publication year - 2017
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2016jd026094
Subject(s) - surface finish , facet (psychology) , surface roughness , ice crystals , optics , materials science , remote sensing , geology , physics , composite material , psychology , social psychology , personality , big five personality traits
We present a method for inferring surface morphology of ice from scanning electron microscope images. We first develop a novel functional form for the backscattered electron intensity as a function of ice facet orientation; this form is parameterized using smooth ice facets of known orientation. Three‐dimensional representations of rough surfaces are retrieved at approximately micrometer resolution using Gauss‐Newton inversion within a Bayesian framework. Statistical analysis of the resulting data sets permits characterization of ice surface roughness with a much higher statistical confidence than previously possible. A survey of results in the range −39°C to −29°C shows that characteristics of the roughness (e.g., Weibull parameters) are sensitive not only to the degree of roughening but also to the symmetry of the roughening. These results suggest that roughening characteristics obtained by remote sensing and in situ measurements of atmospheric ice clouds can potentially provide more facet‐specific information than has previously been appreciated.