An examination of parameterizations for the CCN number concentration based on in situ measurements of aerosol activation properties in the North China Plain

Abstract

Precise quantification of the cloud condensation nuclei (CCN) number concentration is crucial for understanding aerosol indirect effects and characterizing these effects in models. An evaluation of various methods for CCN parameterization was carried out in this paper based on in situ measurements of aerosol activation properties within HaChi (Haze in China) project. Comparisons were made by closure studies between methods using CCN spectra, bulk activation ratios, cut-off diameters and size-resolved activation ratios. The estimation of CCN number concentrations by the method using aerosol size-resolved activation ratios, either averaged over a day or with diurnal variation, was found to be most satisfying and straightforward. This could be well expected since size-resolved activation ratios include information regarding the effects of size-resolved chemical compositions and mixing states on aerosol activation properties. The method using the averages of critical diameters, which were inferred from measured CCN number concentrations and particle number size distributions, also provided a good prediction of the CCN number concentration. Based on comparisons of all these methods in this paper, it was recommended that the CCN number concentration be predicted using particle number size distributions with inferred critical diameters or size-resolved activation ratios

Investigation of the effective peak supersaturation for liquid-phase clouds at the high-alpine site Jungfraujoch, Switzerland (3580 m a.s.l.)

“…Many studies have used CCN counters to investigate the critical supersaturation of ambient aerosol particles as well as the CCN number concentration under controlled supersaturation conditions (e.g. Fors et al, 2011;Padro et al, 2012;Deng et al, 2013;Sihto et al, 2011).…”

Aerosol hygroscopicity and cloud condensation nuclei activity during the AC<sup>3</sup>Exp campaign: implications for cloud condensation nuclei parameterization

“…Studies have addressed the relative importance of the size distribution, particle composition, and mixing state in determining CCN activation, but there are disagreements on the relative importance of these parameters (e.g., Roberts et al, 2002;Feingold, 2003;Ervens et al, 2005;Mircea et al, 2005;Dusek et al, 2006a;Anttila and Kerminen, 2007;Hudson, 2007;Quinn et al, 2008;Zhang et al, 2008;Deng et al, 2013. CCN closure studies are a useful approach to test our knowledge of the controlling physical and chemical factors and to help verify experimental results.…”

Impacts of organic aerosols and its oxidation level on CCN activity from measurement at a suburban site in China

“…In recent years, CCN measurements have been collected during field campaigns carried out in the region (Wiedensohler et al, 2009;Gunthe et al, 2011;Yue et al, 2011;Deng et al, 2011Deng et al, , 2013Zhang et al, 2014). These studies have presented different perspectives on the influence of particle size and composition on CCN activity.…”

“…These studies have presented different perspectives on the influence of particle size and composition on CCN activity. For example, Deng et al (2013) evaluated various schemes for CCN parameterization and recommended that the particle number size distribution (PSD) together with inferred mean size-resolved activation ratios can be used to estimate CCN number concentrations without considering the impact of particle composition. However, Zhang et al (2014) demonstrated that the 30-40 % uncertainties in N CCN are mainly associated with changes in particle composition.…”