Aerosol hygroscopicity and cloud condensation nuclei activity during the AC&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;Exp  campaign: implications for cloud condensation nuclei parameterization

Zhang, F.; Li, Y.; Li, Zhenwang; Sun, Liqiang; Li, R.; Zhao, Chuanfeng; Wang, Pucai; Sun, Yele; Liu, X.; Li, J.; Li, P.; Ren, Gang; Fan, Tianyi

doi:10.5194/acp-14-13423-2014

Cited by 78 publications

(79 citation statements)

References 80 publications

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“…Note that the maximum activation fraction (MAF) for Xianghe site showed in Fig. 1 is slight lower than that we plotted in Zhang et al (2014). Because some data points with MAF value > 1 were also included previously, larger mean MAF resulted.…”

Section: Ccn Efficiency Spectramentioning

confidence: 79%

“…The method is very similar to that used by Zhang et al (2014). As proposed by Petters and Kreidenweis (2007), κ chem can be predicted using a simple mixing rule based on chemical volume fractions for a given internal mixture:…”

Section: Derivation Of κ Chemmentioning

confidence: 93%

“…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. None of the above-mentioned studies have investigated the impact of organics on estimating N CCN in Northern China.…”

Section: Introductionmentioning

confidence: 99%

“…This is likely due to the organics component of aerosol particles, which have the largest uncertainty and are not fully understood. Biomass burning aerosols and secondary organics formed from the oxidation of common biogenic emissions are often more difficult to activate (Mircea et al, 2005;VanReken et al, 2005;Lee et al, 2006;Varutbangkul et al, 2006;Clarke et al, 2007;Rose et al, 2010;Engelhart et al, 2012;Paramonov et al, 2013;Lathem et al, 2013;Mei et al, 2013b;Zhang et al, 2014). Particles with aged/oxidized secondary organic components (e.g., organic acids) have been shown to be more hygroscopic (Raymond and Pandis, 2002;Hartz et al, 2006;Bougiatioti et al, 2011) but still much less hygroscopic than inorganic species.…”

Section: Introductionmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Zhang

Sun

et al. 2016

Atmos. Chem. Phys.

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Abstract. This study is concerned with the impacts of organic aerosols on cloud condensation nuclei (CCN) activity based on field measurements made at a suburban site in Northern China. The sensitivity of the estimated CCN number concentration (N CCN ) to both volume fraction of organic material (x org ) and aerosol oxidation level (using f 44 , the fraction of m/z 44 in aerosol organic material) are examined. A strong dependence of CCN number concentration (N CCN ) on the x org and f 44 was noted. The sensitivity of N CCN to volume fraction of organics increased with increasing x org . The impacts of the aerosol particles oxidization or aging level on estimating N CCN were also very significant. When the particles were mostly composed of organics (x org > 60 %), the N CCN at the supersaturation of 0.075 and 0.13 % was underestimated by 46 and 44 %, respectively, if aerosol particles were freshly emitted with primary organics (f 44 < 11 %); the underestimation decreased to 32 and 23 % at the corresponding supersaturations, however, if the particles were with more hygroscopic secondary organics (f 44 > 15 %). The N CCN at the supersaturation of 0.76 % was underestimated by 11 and 4 %, respectively, at f 44 < 11 and f 44 > 15 %. However, for the particles composed of low organics (e.g., x org < 40 %), the effect caused by the f 44 was quite insignificant both at high and low supersaturations. This is because the overall hygroscopicity of the particles is dominated by inorganics such as sulfate and nitrate, which are more hygroscopic than organic compounds. Our results indicated that it would decrease the uncertainties in estimating N CCN and lead to a more accurate estimation of N CCN to increase the proportion of secondary organics, especially when the composition of the aerosols is dominated by organics. The applicability of the CCN activation spectrum obtained at Xinzhou to the Xianghe site, about 400 km to the northeast of Xinzhou, was investigated, with the aim of further examining the sensitivity of N CCN to aerosol type. Overall, the mean CCN efficiency spectrum derived from Xinzhou performs well at Xianghe when the supersaturation levels are > 0.2 % (overestimation of 2-4 %). However, N CCN was overestimated by ∼ 20 % at supersaturation levels of < 0.1 %. This suggests that the overestimation is mainly due to the smaller proportion of aged and oxidized organic aerosols present at Xianghe compared to Xinzhou.

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Section: Ccn Efficiency Spectramentioning

confidence: 79%

Section: Derivation Of κ Chemmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Zhang

Sun

et al. 2016

Atmos. Chem. Phys.

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Aerosol characterization over the North China Plain: Haze life cycle and biomass burning impacts in summer

et al. 2016

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The North China Plain experiences frequent severe haze pollution during all seasons. Here we present the results from a summer campaign that was conducted at Xianghe, a suburban site located between the megacities of Beijing and Tianjin. Aerosol particle composition was measured in situ by an Aerosol Chemical Speciation Monitor along with a suite of collocated measurements during 1-30 June 2013. Our results showed that aerosol composition at the suburban site was overall similar to that observed in Beijing, which was mainly composed of organics (39%), nitrate (20%), and sulfate (18%). Positive matrix factorization of organic aerosol (OA) identified four OA factors with different sources and processes. While secondary organic aerosol dominated OA, on average accounting for 70%, biomass burning OA (BBOA) was also observed to have a considerable contribution (11%) for the entire study period. The contribution of BBOA was increased to 21% during the BB period in late June, indicating a large impact of agricultural burning on air pollution in summer. Biomass burning also exerted a significant impact on aerosol optical properties. It was estimated that~60% enhancement of absorption at the ultraviolet spectral region was caused by the organic compounds from biomass burning. The formation mechanisms and sources of severe haze pollution episodes were investigated in a case study. The results highlighted two different mechanisms, i.e., regional transport and local sources, driving the haze life cycles differently in summer in the North China Plain. While secondary aerosol species dominated aerosol composition in the episode from regional transport, organics and black carbon comprised the major fraction in the locally formed haze episode.

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Aerosol and monsoon climate interactions over Asia

Lau

Ramanathan

et al. 2016

Reviews of Geophysics

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The increasing severity of droughts/floods and worsening air quality from increasing aerosols in Asia monsoon regions are the two gravest threats facing over 60% of the world population living in Asian monsoon regions. These dual threats have fueled a large body of research in the last decade on the roles of aerosols in impacting Asian monsoon weather and climate. This paper provides a comprehensive review of studies on Asian aerosols, monsoons, and their interactions. The Asian monsoon region is a primary source of emissions of diverse species of aerosols from both anthropogenic and natural origins. The distributions of aerosol loading are strongly influenced by distinct weather and climatic regimes, which are, in turn, modulated by aerosol effects. On a continental scale, aerosols reduce surface insolation and weaken the land-ocean thermal contrast, thus inhibiting the development of monsoons. Locally, aerosol radiative effects alter the thermodynamic stability and convective potential of the lower atmosphere leading to reduced temperatures, increased atmospheric stability, and weakened wind and atmospheric circulations. The atmospheric thermodynamic state, which determines the formation of clouds, convection, and precipitation, may also be altered by aerosols serving as cloud condensation nuclei or ice nuclei. Absorbing aerosols such as black carbon and desert dust in Asian monsoon regions may also induce dynamical feedback processes, leading to a strengthening of the early monsoon and affecting the subsequent evolution of the monsoon. Many mechanisms have been put forth regarding how aerosols modulate the amplitude, frequency, intensity, and phase of different monsoon climate variables. A wide range of theoretical, observational, and modeling findings on the Asian monsoon, aerosols, and their interactions are synthesized. A new paradigm is proposed on investigating aerosol-monsoon interactions, in which natural aerosols such as desert dust, black carbon from biomass burning, and biogenic aerosols from vegetation are considered integral components of an intrinsic aerosol-monsoon climate system, subject to external forcing of global warming, anthropogenic aerosols, and land use and change. Future research on aerosol-monsoon interactions calls for an integrated approach and international collaborations based on long-term sustained observations, process measurements, and improved models, as well as using observations to constrain model simulations and projections.

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

Cited by 78 publications

References 80 publications

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

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

Aerosol characterization over the North China Plain: Haze life cycle and biomass burning impacts in summer

Aerosol and monsoon climate interactions over Asia

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