Theoretical seminar | 17 November 2021

Remote sensing is the art of retrieving information at a distance. On a fundamental level, this implies the retrieval of physical and chemical properties (such as size, refractive index, shape, etc) of target particles from characteristics of the electromagnetic radiation that interacted with the target. In practice, however, analysis and interpretation of remote-sensing measurements of the atmospheric aerosols and/or cosmic dust are often based on oversimplified models of light scattering by a perfect sphere or perfect spheroids; whereas, it is well-known, neither of those resemble the highly irregular shape in true dust particles. I have developed realistic models of dust particles that incorporate their highly irregular morphology and study light scattering by dust particles as a function of their physical and chemical parameters. This significantly differs from the oversimplified models of spheres and/or spheroidal particles that are frequently involved into analysis of astronomical observations and laboratory measurements. However, the realistic approach improves the reliability of the analysis and, thus, significantly enhances the scientific return from the measurements and observations. This will be demonstrated via modeling of laboratory optical measurements of feldspar particles (an abundant species of the terrestrial desert dust) and polarimetric response measured in astronomical observations of various comets (major source of interplanetary dust particles in our Solar System). Furthermore, an extremely important advantage of using realistic models is that there is a direct correlation between the model parameters and the actual physical parameters of the dust. It makes it possible further development of remote-sensing technique. Several examples of this development will be also demonstrated in my talk.

Main paper/arXiv, related to the seminar, and other references

1. E. Zubko et al. 2013. Light scattering by feldspar particles: comparison of model agglomerate debris particles with laboratory samples. J. Quant. Spectrosc. Radiat. Transfer, 131, 175–187; https://doi.org/10.1016/j.jqsrt.2013.01.017
2. E. Zubko et al. 2016. The positive-polarization of cometary comae. Planet. Space Sci., 123, 63–76; https://doi.org/10.1016/j.pss.2015.09.020
3. E. Zubko et al. 2017. Umov effect in single-scattering dust particles: Effect of irregular shape. Opt. Lett., 42, 1962–1965; https://doi.org/10.1364/OL.42.001962
4. E. Zubko et al. 2021. Active remote sensing of atmospheric dust using relationships between their depolarization ratios and reflectivity. Opt. Lett., 46, 2352–2355; https://doi.org/10.1364/OL.426584