Aerosol properties computed from aircraft-based observations during the ACE-Asia campaign: 1. Aerosol size distributions retrieved from optical thickness measurements

Journal Article · Tue Apr 03 04:00:00 EDT 2007 · Aerosol Science and Technology, 41(2):202-216

DOI:https://doi.org/10.1080/02786820601126789· OSTI ID:902038

Kuzmanoski, Maja; Box, M A; Box, G P; Schmid, Beat; Wang, Jian; Russell, P B; Jonsson, Haf; Seinfeld, J H

In this paper aerosol size distributions retrieved from aerosol layer optical thickness spectra, derived from the 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) measurements during the ACE-Asia campaign, are presented. Focusing on distinct aerosol layers (with different particle characteristics) observed in four vertical profiles, we compare the results of two different retrieval methods: constrained linear inversion and a non-linear least squares method. While the former does not use any assumption about the analytical form of the size distribution, the latter was used to retrieve parameters of a bimodal lognormal size distribution. Furthermore, comparison of the retrieved size distributions with those measured in-situ, aboard the same aircraft on which the sunphotometer was flown, was carried out. Results of the two retrieval methods showed good agreement in the radius ranges from ~0.1μm to ~1.2-2.0μm, close to the range of retrievable size distributions from the AATS-14 measurements. In this radius interval, shapes of retrieved and measured size distributions were similar, in accord with close wavelength dependencies of the corresponding optical thicknesses. Additionally, the effect of a size-resolved refractive index on the retrieved size spectra was investigated in selected cases. Retrieval using a constant refractive index pertaining to particle sizes within the range of retrievable size distributions resulted in a size distribution very close to the one retrieved using a size-resolved refractive index.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 902038
• Report Number(s): PNNL-SA-54427
• Journal Information: Aerosol Science and Technology, 41(2):202-216, Journal Name: Aerosol Science and Technology, 41(2):202-216 Journal Issue: 2 Vol. 41; ISSN 0278-6826; ISSN ASTYDQ
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AEROSOLS
AIRCRAFT
DISTRIBUTION
PARTICLE SIZE
PHOTOMETRY
REFRACTIVE INDEX
SPECTRA
THICKNESS