Aerosol nucleation induced by a high energy particle beam

Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke; Uggerhøj, U. I.; Paling, S. M.; Svensmark, Henrik

doi:10.1029/2011gl047036

Cited by 61 publications

(51 citation statements)

References 26 publications

(34 reference statements)

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“…It is hypothesised that if some of these CCN are created through cosmic ray ionisation then global CCN could be influenced by the cosmic ray ionisation rate. The nucleation rate has been shown experimentally to increase with ion concentrations (Kirkby et al, 2011;Enghoff et al, 2011). Pierce and Adams (2009a) found that the effect of changes in cosmic rays over a solar cycle on CCN concentrations would be two orders of magnitude too small to account for observed changes in cloud properties.…”

Section: Introductionmentioning

confidence: 99%

No statistically significant effect of a short-term decrease in the nucleation rate on atmospheric aerosols

et al. 2012

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Abstract.Observed correlations between short-term decreases in cosmic ray ionisation and cloud and aerosol properties have been attributed to short-term decreases in the ion-induced nucleation rate. We use a global aerosol microphysics model to determine whether a 10 day reduction of 15 % in the nucleation rate could generate a statistically significant response in aerosol concentrations and optical properties. As an upper limit to the possible effect of changes in ion-induced nucleation rate, we perturb the total nucleation rate, which has been shown to generate particle concentrations and nucleation events in reasonable agreement with global observations. When measured against a known aerosol control state, the model predicts a 0.15 % decrease in global mean cloud condensation nucleus concentration at the surface. However, taking into account the variability in aerosol, no statistically significant response can be detected in concentrations of particles with diameters larger than 10 nm, in cloud condensation nuclei with diameters larger than 70 nm, or in theÅngström exponent. The results suggest that the observed correlation between short-term decreases in cosmic ray ionisation and cloud and aerosol properties cannot be explained by associated changes in the largescale nucleation rate.

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Section: Introductionmentioning

confidence: 99%

No statistically significant effect of a short-term decrease in the nucleation rate on atmospheric aerosols

et al. 2012

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“…Statistical correlation studies are inconclusive and lead to contradictory results largely because the contemporary fast expansion of the anthropogenic factor makes it difficult to study the natural variability of the terrestrial system, including the solar factor, by means of statistical/phenomenological methods. Direct laboratory and in situ experiments (Kulmala et al, 2010;Kirkby et al, 2011;Enghoff et al, 2011) suggest that enhanced ionization may lead to aerosol particle formation in the realistic conditions, but this effect is small. There are also some global aerosol microphysics model studies testing the sensitivity of cloud condensation nuclei (CCN) concentration to the changes in nucleation that might occur due to changes in cosmic rays.…”

Section: Introductionmentioning

confidence: 99%

Possible effect of extreme solar energetic particle events of September–October 1989 on polar stratospheric aerosols: a case study

Mironova

Usoskin

2013

Atmos. Chem. Phys.

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Abstract. The main ionization source of the middle and low Earth's atmosphere is related to energetic particles coming from outer space. Usually it is ionization from cosmic rays that is always present in the atmosphere. But in a case of a very strong solar eruption, some solar energetic particles (SEPs) can reach middle/low atmosphere increasing the ionization rate up to some orders of magnitude at polar latitudes. We continue investigating such a special class of solar events and their possible applications for natural variations of the aerosol content. After the case study of the extreme SEP event of January 2005 and its possible effect upon polar stratospheric aerosols, here we analyze atmospheric applications of the sequence of several events that took place over autumn 1989. Using aerosol data obtained over polar regions from two satellites with space-borne optical instruments SAGE II and SAM II that were operating during September–October 1989, we found that an extreme major SEP event might have led to formation of new particles and/or growth of preexisting ultrafine particles in the polar stratospheric region. However, the effect of the additional ambient air ionization on the aerosol formation is minor, in comparison with temperature effect, and can take place only in the cold polar atmospheric conditions. The extra aerosol mass formed under the temperature effect allows attributing most of the changes to the "ion–aerosol clear sky mechanism".

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“…Experimental evidence for a microphysical mechanism was first reported in 2007 [10] and further experiments have recently added to its credibility [11,12]. These experiments initially showed that an increase in ionization leads to an increase in the formation of ultrafine aerosols (≈ 3 nm), but in the real atmosphere such small particles have to grow by coagulation and intake of condensable gases to become cloud condensation nuclei (CCN) (> 50 nm) in order to have an effect on clouds [13, chapter 17].…”

mentioning

confidence: 99%

Response of cloud condensation nuclei (>50 nm) to changes in ion-nucleation

2013

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In experiments where ultraviolet light produces aerosols from trace amounts of ozone, sulphur dioxide, and water vapour, the number of additional small particles produced by ionization by gamma sources all grow up to diameters larger than 50 nm, appropriate for cloud condensation nuclei. This result contradicts both ion-free control experiments and also theoretical models that predict a decline in the response of larger particles due to an insufficiency of condensable gases (which leads to slower growth) and to larger losses by coagulation between the particles. This unpredicted experimental finding points to a process not included in current theoretical models, possibly an ion-induced formation of sulphuric acid in small clusters.

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Aerosol nucleation induced by a high energy particle beam

Cited by 61 publications

References 26 publications

No statistically significant effect of a short-term decrease in the nucleation rate on atmospheric aerosols

No statistically significant effect of a short-term decrease in the nucleation rate on atmospheric aerosols

Possible effect of extreme solar energetic particle events of September–October 1989 on polar stratospheric aerosols: a case study

Response of cloud condensation nuclei (>50 nm) to changes in ion-nucleation

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