Characterizing the size and absorption of single nonspherical aerosol particles from angularly-resolved elastic light scattering. (February 2019)

• Record Type: Journal Article
• Authors: Walters, Sequoyah; Zallie, Jason; Seymour, Gabriel; Pan, Yong-Le; Videen, Gorden; Aptowicz, Kevin B.
• Is Part Of: Journal of quantitative spectroscopy & radiative transfer. Volume 224(2019)
• Page Start: 439
• Page End: 444
• Publication Date: 2019-02
• Subjects: Single particle -- Absorption -- Elastic light scattering -- Aerosol; Spectrum analysis -- Periodicals; Radiation -- Periodicals; Analyse spectrale -- Périodiques; Rayonnement -- Périodiques; Radiation; Spectrum analysis; Periodicals; 543.0858
• DOI: 10.1016/j.jqsrt.2018.12.005
• Languages: English
• ISSNs: 0022-4073

Abstract

Highlights: Speckle size from two-dimensional angular optical scattering (TAOS) is strongly negatively correlated with cluster size of aerosol. Simulations show that analysis of two-dimensional angular optical scattering (TAOS) is able to distinguish between non-absorbing, weakly-absorbing, and strongly-absorbing single aerosol particles. Abstract: Measuring the absorption of a single aerosol particle is a challenging endeavor. Of the few techniques available, none are suitable for measuring the single-particle absorption of coarse-mode nonspherical aerosols. Analysis of two-dimensional angular optical scattering (TAOS) patterns provide a possible pathway to perform this measurement. Using a Multiple-Sphere T-Matrix (MSTM) code, we simulate the captured TAOS patterns with geometries similar to a previously designed instrument. By analyzing the size of the speckle and the integrated irradiance of these simulated TAOS patterns, we are able to distinguish between high-absorbing, weak-absorbing, and non-absorbing particles over the size range of 2 µm to 10 µm. In particular, the speckle present in the scattering patterns provides a means to estimate the size of the particle. Once the size of the particle is known, the integrated irradiance provides insight into the absorption of the particle.