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Cloud droplet nucleation scavenging in relation to the size and hygroscopic behaviour of aerosol particles

Svenningsson, Birgitta LU ; Hansson, Hans Christen ; Martinsson, Bengt LU ; Wiedensohler, Alfred ; Swietlicki, Erik LU orcid ; Cederfelt, Sven Inge ; Wendisch, Manfred ; Bower, Keith N. ; Choularton, Tom W. and Colvile, Roy N. (1997) In Atmospheric Environment 31(16). p.2463-2475
Abstract

The size distributions and hygroscopic growth spectra of aerosol particles were measured during the GCE cloud experiment at Great Dun Fell in the Pennine Hills in northern England. Hygroscopic growth is defined as the particle diameter at 90% RH divided by the particle diameter at 10% RH. The fraction of the aerosol particles scavenged by cloud droplets as a function of particle size was also measured. The general aerosol type was a mixture of marine and aged anthropogenic aerosols. The Aitken and accumulation mode numbers (average ± 1 S.D.) were 1543 ± 1078 and 1023 ± 682 cm-3, respectively. The mean diameters were in the range 30-100 nm and 100-330 nm. The hygroscopic growth spectra were bimodal about half the time. The... (More)

The size distributions and hygroscopic growth spectra of aerosol particles were measured during the GCE cloud experiment at Great Dun Fell in the Pennine Hills in northern England. Hygroscopic growth is defined as the particle diameter at 90% RH divided by the particle diameter at 10% RH. The fraction of the aerosol particles scavenged by cloud droplets as a function of particle size was also measured. The general aerosol type was a mixture of marine and aged anthropogenic aerosols. The Aitken and accumulation mode numbers (average ± 1 S.D.) were 1543 ± 1078 and 1023 ± 682 cm-3, respectively. The mean diameters were in the range 30-100 nm and 100-330 nm. The hygroscopic growth spectra were bimodal about half the time. The less-hygroscopic particles had average growth factors of 1.06, 1.06; 1.03, 1.03, and 1.03 for particle diameters of 50, 75, 110, 165, and 265 nm, respectively. For the more-hygroscopic particles of the same sizes, the average hygroscopic growth was 1.34, 1.37, 1.43, 1.47, and 1.53. The effects of ageing on the aerosol particle size distribution and on hygroscopic behaviour are discussed. The scavenged fraction of aerosol particles was a strong function of particle diameter. The diameter with 50% scavenging was in the range 90-220 nm. No tail of smaller particles activated to cloud drops was observed. A small tail of larger particles that remained in the interstitial aerosol can be explained by there being a small fraction of less-hygroscopic particles. A weak correlation between the integral dry particle diameter and the diameter with 50% scavenging was seen.

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author
; ; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cloud condensation nuclei, External mixing, Hygroscopic growth, Size distribution, Soluble fraction
in
Atmospheric Environment
volume
31
issue
16
pages
13 pages
publisher
Elsevier
external identifiers
  • scopus:0030616210
ISSN
1352-2310
DOI
10.1016/S1352-2310(96)00179-3
language
English
LU publication?
yes
id
3ad565c0-04bb-4ab0-bc39-7dfc080ce0aa
date added to LUP
2019-05-16 09:19:01
date last changed
2022-01-31 20:01:06
@article{3ad565c0-04bb-4ab0-bc39-7dfc080ce0aa,
  abstract     = {{<p>The size distributions and hygroscopic growth spectra of aerosol particles were measured during the GCE cloud experiment at Great Dun Fell in the Pennine Hills in northern England. Hygroscopic growth is defined as the particle diameter at 90% RH divided by the particle diameter at 10% RH. The fraction of the aerosol particles scavenged by cloud droplets as a function of particle size was also measured. The general aerosol type was a mixture of marine and aged anthropogenic aerosols. The Aitken and accumulation mode numbers (average ± 1 S.D.) were 1543 ± 1078 and 1023 ± 682 cm<sup>-3</sup>, respectively. The mean diameters were in the range 30-100 nm and 100-330 nm. The hygroscopic growth spectra were bimodal about half the time. The less-hygroscopic particles had average growth factors of 1.06, 1.06; 1.03, 1.03, and 1.03 for particle diameters of 50, 75, 110, 165, and 265 nm, respectively. For the more-hygroscopic particles of the same sizes, the average hygroscopic growth was 1.34, 1.37, 1.43, 1.47, and 1.53. The effects of ageing on the aerosol particle size distribution and on hygroscopic behaviour are discussed. The scavenged fraction of aerosol particles was a strong function of particle diameter. The diameter with 50% scavenging was in the range 90-220 nm. No tail of smaller particles activated to cloud drops was observed. A small tail of larger particles that remained in the interstitial aerosol can be explained by there being a small fraction of less-hygroscopic particles. A weak correlation between the integral dry particle diameter and the diameter with 50% scavenging was seen.</p>}},
  author       = {{Svenningsson, Birgitta and Hansson, Hans Christen and Martinsson, Bengt and Wiedensohler, Alfred and Swietlicki, Erik and Cederfelt, Sven Inge and Wendisch, Manfred and Bower, Keith N. and Choularton, Tom W. and Colvile, Roy N.}},
  issn         = {{1352-2310}},
  keywords     = {{Cloud condensation nuclei; External mixing; Hygroscopic growth; Size distribution; Soluble fraction}},
  language     = {{eng}},
  number       = {{16}},
  pages        = {{2463--2475}},
  publisher    = {{Elsevier}},
  series       = {{Atmospheric Environment}},
  title        = {{Cloud droplet nucleation scavenging in relation to the size and hygroscopic behaviour of aerosol particles}},
  url          = {{http://dx.doi.org/10.1016/S1352-2310(96)00179-3}},
  doi          = {{10.1016/S1352-2310(96)00179-3}},
  volume       = {{31}},
  year         = {{1997}},
}