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Refractive Index for Asian Dust in the Ultraviolet‐Visible Region Determined From Compositional Analysis and Validated With OMI Observations
Author(s) -
Lee KwangMog,
Choi Haklim,
Kim Jhoon
Publication year - 2020
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2019jd030629
Subject(s) - mineral dust , asian dust , refractive index , mineral , mineralogy , atmospheric sciences , ozone monitoring instrument , wavelength , pyroxene , environmental science , materials science , aerosol , geology , physics , olivine , meteorology , troposphere , optoelectronics , metallurgy
Asian dust aerosols consist of various minerals, such as quartz, clay minerals, feldspars, and calcite. Complex refractive index of Asian dust is determined for a spectral range from 0.2 to 1.0 μm, assuming that the particles are an internal mixture of the component minerals in dust samples reported in previous literature. The derived optical constants for Asian dust are quite different from the refractive indices for other desert dusts. The imaginary refractive index for Asian dust is much smaller than that of the “mineral” model in Optical Properties of Aerosols and Clouds (OPAC) across the whole range. At wavelengths shorter than 650 nm, the present imaginary index is smaller than the index for Saharan dust, determined from mineralogical compositions of dust samples at Tinfou, Morocco, during the Saharan Mineral Dust Experiment (SAMUM). The simulated spectrum for an Asian dust event on 15 March 2009 in north‐east China using the present optical constants agree well with the spectrum measured by the Ozone Monitoring Instrument (OMI) on board the Aura spacecraft.