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Empirical Relationships Between Optical Properties and Equivalent Diameters of Fractal Soot Aggregates at 550 Nm Wavelength.Soot aggregates (SAs)-fractal clusters of small, spherical carbonaceous monomers-modulate the incoming visible solar radiation and contribute significantly to climate forcing. Experimentalists and climate modelers typically assume a spherical morphology for SAs when computing their optical properties, causing significant errors. Here, we calculate the optical properties of freshly-generated (fractal dimension Df = 1.8) and aged (Df = 2.6) SAs at 550 nm wavelength using the numericallyexact superposition T-Matrix method. These properties were expressed as functions of equivalent aerosol diameters as measured by contemporary aerosol instruments. This work improves upon previous efforts wherein SA optical properties were computed as a function of monomer number, rendering them unusable in practical applications. Future research will address the sensitivity of variation in refractive index, fractal prefactor, and monomer overlap of SAs on the reported empirical relationships.
Document ID
20150022194
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Pandey, Apoorva (Washington Univ. Saint Louis, MO, United States)
Chakrabarty, Rajan K. (Washington Univ. Saint Louis, MO, United States)
Liu, Li (NASA Goddard Inst. for Space Studies New York, NY, United States)
Mishchenko, Michael I. (NASA Goddard Inst. for Space Studies New York, NY, United States)
Date Acquired
December 2, 2015
Publication Date
September 24, 2015
Publication Information
Publication: Optics Express
Volume: 23
Issue: 24
Subject Category
Optics
Report/Patent Number
GSFC-E-DAA-TN27298
Funding Number(s)
CONTRACT_GRANT: NNX15AI66G
Distribution Limits
Public
Copyright
Other
Keywords
deuterium fluorides
monomers
fractals
optical properties
climate
aerosols
SAS