Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 6651-6662, 2017
https://doi.org/10.5194/acp-17-6651-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
07 Jun 2017
A novel method for deriving the aerosol hygroscopicity parameter based only on measurements from a humidified nephelometer system
Ye Kuang1, Chunsheng Zhao1, Jiangchuan Tao1, Yuxuan Bian2, Nan Ma3, and Gang Zhao1 1Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing, China
2State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, China
3Leibniz Institute for Tropospheric Research, Leipzig, Germany
Abstract. Aerosol hygroscopicity is crucial for understanding roles of aerosol particles in atmospheric chemistry and aerosol climate effects. Light-scattering enhancement factor f(RH, λ) is one of the parameters describing aerosol hygroscopicity, which is defined as f(RH, λ) = σsp(RH, λ)∕σsp(dry, λ), where σsp(RH, λ) or σsp(dry, λ) represents σsp at wavelength λ under certain relative humidity (RH) or dry conditions. Traditionally, an overall hygroscopicity parameter κ can be retrieved from measured f(RH, λ), hereinafter referred to as κf(RH), by combining concurrently measured particle number size distribution (PNSD) and mass concentration of black carbon. In this paper, a new method is proposed to directly derive κf(RH) based only on measurements from a three-wavelength humidified nephelometer system. The advantage of this newly proposed approach is that κf(RH) can be estimated without any additional information about PNSD and black carbon. This method is verified with measurements from two different field campaigns. Values of κf(RH) estimated from this new method agree very well with those retrieved by using the traditional method: all points lie near the 1 : 1 line and the square of correlation coefficient between them is 0.99. The verification results demonstrate that this newly proposed method of deriving κf(RH) is applicable at different sites and in seasons of the North China Plain and might also be applicable in other regions around the world.

Citation: Kuang, Y., Zhao, C., Tao, J., Bian, Y., Ma, N., and Zhao, G.: A novel method for deriving the aerosol hygroscopicity parameter based only on measurements from a humidified nephelometer system, Atmos. Chem. Phys., 17, 6651-6662, https://doi.org/10.5194/acp-17-6651-2017, 2017.
Publications Copernicus
Download
Short summary
A novel approach is proposed in this research to derive the aerosol hygroscopicity parameter based only on measurements from a humidified nephelometer system without any additional information about particle number size distribution and black carbon. New findings in this research can bridge the gap between κ-Köhler theory and the aerosol light-scattering enhancement factor and will make the humidified nephelometer system more convenient when it comes to aerosol hygroscopicity research.
A novel approach is proposed in this research to derive the aerosol hygroscopicity parameter...
Share