Ion‐aerosol‐cloud processes in the lower atmosphere

Harrison, Giles; Carslaw, K. S.

doi:10.1029/2002rg000114

Cited by 338 publications

(352 citation statements)

References 155 publications

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“…The possible effect of image charges can be important as well but it is not included in this model. The presence of ions at SMEAR II (Laakso et al, 2004), and work by Tinsley et al (2000), Tripathi and Harrison (2001), Harrison and Carslaw (2003) indicate that electrostatic charge image interaction is possible between AP and raindrops. There is not yet a direct experimental account of the role of electric charge in UFP scavenging, and in the rest of the paper we will show results only for neutral particles.…”

Section: Effective Scavenging Coefficientmentioning

confidence: 99%

Scavenging of ultrafine particles by rainfall at a boreal site: observations and model estimations

et al. 2006

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Abstract.Values of the scavenging coefficient determined from observations of ultrafine particles (with diameters in the range 10-510 nm) during rain events at a boreal forest site in Southern Finland between 1996 and 2001 were reported by Laakso et al. (2003a). The estimated range of the median values of the scavenging coefficient was [7×10 −6 −4×10 −5 ] s −1 , which is generally higher than model calculations based only on below-cloud processes (Brownian diffusion, interception, and typical phoretic and charge effects).In the present study, in order to interpret these observed data on scavenging coefficients from Laakso et al. (2003a), we use a model that includes below-cloud scavenging processes, mixing of ultrafine particles from the boundary layer (BL) into cloud, followed by cloud condensation nuclei activation and in-cloud removal by rainfall. The range of effective scavenging coefficient predicted by the new model, corresponding to wide ranges of values of its input parameters, are compared with observations. Results show that ultrafine particle removal by rain depends on aerosol size, rainfall intensity, mixing processes between BL and cloud elements, in-cloud scavenged fraction, in-cloud collection efficiency, and in-cloud coagulation with cloud droplets.The scavenging coefficients predicted by the new model are found to be significantly sensitive to the choice of representation of: (1) mixing processes; (2) raindrop size distribution; (3) phoretic effects in aerosol-raindrop collisions; and (4) cloud droplet activation. Implications for future studies of BL ultrafine particles scavenging are discussed.

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Section: Effective Scavenging Coefficientmentioning

confidence: 99%

Scavenging of ultrafine particles by rainfall at a boreal site: observations and model estimations

et al. 2006

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“…The attractive potential between ions and ions and between ions and the dipole moment (induced or not) of the condensable vapor reduces the thermodynamic barrier for nucleation and hence, enhances the condensational growth (Lovejoy et al, 2004;Nadykto and Yu, 2004). Conflicting views about the relative importance of IMN subsist between modelling studies (see for example Laakso et al, 2002;Harrisson and Carslaw, 2003;Yu et al, 2008) which assess that IMN should be an important source of atmospheric particles and field measurements (see for example Eisele et al, 2006;Manninen et al, 2009) who show that the contribution of IMN to new particle formation in planetary boundary layer (PBL) is less than 10% in average. In any case, the charged fraction of clusters and particles is a good indicator of the presence of neutral clusters and particles.…”

mentioning

confidence: 99%

New particle formation and ultrafine charged aerosol climatology at a high altitude site in the Alps (Jungfraujoch, 3580 m a.s.l., Switzerland)

et al. 2010

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Atmospheric Chemistry and PhysicsNew particle formation and ultrafine charged aerosol climatology at a high altitude site in the Alps (Jungfraujoch, 3580 m a.s.l., Switzerland) Abstract. We investigate the formation and growth of charged aerosols clusters at Jungfraujoch, in the Swiss Alps (3580 m a.s.l.), the highest altitude site of the European EU-CAARI project intensive campaign. Charged particles and clusters (0.5 − 1.8 nm) were measured from April 2008 to April 2009 and allowed the detection of nucleation events in this very specific environment (presence of free tropospheric air and clouds). We found that the naturally charged aerosol concentrations, which are dominated by the cluster size class, shows a strong diurnal pattern likely linked to valley breezes transporting surface layer ion precursors, presumably radon. Cosmic rays were found not to be the major ion source at the measurement site. However, at night, when air masses are more representative of free tropospheric conditions, we found that the cluster concentrations are still high. The charged aerosol size distribution and concentration are strongly influenced by the presence of clouds at the station. Clouds should be taken into account when deriving high altitude nucleation statistics. New particle formation occurs on average 17.5% of the measurement period and shows a weak seasonality with a minimum of frequency during winter, but this seasonality is enhanced when the data set is screened forCorrespondence to: J. Boulon (j.boulon@opgc.univ-bpclermont.fr) periods when the atmospheric station is out of clouds. The role of ions in the nucleation process was investigated and we found that the ion-mediated nucleation explains 22.3% of the particle formation. The NPF events frequency is correlated with UV radiation but not with calculated H 2 SO 4 concentrations, suggesting that other compounds such as organic vapors are involved in the nucleation and subsequently growth process. In fact, NPF events frequency also surprisingly increases with the condensational sink (CS), suggesting that at Jungfraujoch, the presence of condensing vapours probably coupled with high CS are driving the occurrence of NPF events. A strong link to the air mass path was also pointed out and events were observed to be frequently occurring in Eastern European air masses, which present the highest condensational sink. In these air masses, pre-existing cluster concentrations are more than three time larger than in other air masses during event days, and no new clusters formation is observed, contrarily to what is happening in other air mass types.

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“…Ion-induced nucleation was invoked to explain the correlation between the global cloudiness and the cosmic rays intensity (Carslaw et al, 2002;Harrison and Carslaw, 2003). The temperature-dependent aerosol chamber measurements on the binary H 2 SO 4 -H 2 O nucleation showed that the neutral particle formation is preferred at low temperatures, while ion-induced particle formation dominates at higher temperatures (Duplissy et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Electron-induced chemistry in microhydrated sulfuric acid clusters

2017

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Abstract. We investigate the mixed sulfuric acid-water clusters in a molecular beam experiment with electron attachment and negative ion mass spectrometry and complement the experiment by density functional theory (DFT) calculations. The microhydration of (H 2 SO 4 ) m (H 2 O) n clusters is controlled by the expansion conditions, and the electron attachment yields the main cluster ion series (H 2 SO 4 ) m (H 2 O) n HSO cluster ions point to an efficient caging of the H atom by the surrounding water molecules. The electron-energy dependencies exhibit an efficient electron attachment at low electron energies below 3 eV, and no resonances above this energy, for all the measured mass peaks. This shows that in the atmospheric chemistry only the low-energy electrons can be efficiently captured by the sulfuric acid-water clusters and converted into the negative ions. Possible atmospheric consequences of the acidic dissociation in the clusters and the electron attachment to the sulfuric acid-water aerosols are discussed.

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Ion‐aerosol‐cloud processes in the lower atmosphere

Cited by 338 publications

References 155 publications

Scavenging of ultrafine particles by rainfall at a boreal site: observations and model estimations

Scavenging of ultrafine particles by rainfall at a boreal site: observations and model estimations

New particle formation and ultrafine charged aerosol climatology at a high altitude site in the Alps (Jungfraujoch, 3580 m a.s.l., Switzerland)

Electron-induced chemistry in microhydrated sulfuric acid clusters

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