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Abstract. Relationships between critical supersaturation required for activation and particle dry diameter have been the primary means for experimentally characterizing cloud condensation nuclei (CCN) activity; however, use of the dry diameter inherently limits the application to cases where the dry diameter can be used to accurately estimate solute volume. This study challenges the requirement and proposes a new experimental approach, Wet CCN, for studying CCN activity without the need for a drying step. The new approach directly measures the subsaturated portion of the Köhler curves. The experimental setup consists of a humidity-controlled differential mobility analyzer and a CCN counter; wet diameter equilibrated at known relative humidity is used to characterize CCN activity instead of the dry diameter. The experimental approach was validated against ammonium sulfate, glucose, and nonspherical ammonium oxalate monohydrate. Further, the approach was applied to a mixture of nonspherical iodine oxide particles. The Wet CCN approach successfully determined the hygroscopicity of nonspherical particles by collapsing them into spherical, deliquesced droplets. We further show that the Wet CCN approach offers unique insights into the physical and chemical impacts of the aqueous phase on CCN activity; a potential application is to investigate the impact of evaporation/co-condensation of water-soluble semivolatile species on CCN activity.
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CAESAR: University of California, Riverside Cloud Condensation Nuclei (CCN) Data. Version 1.0
Cloud Condensation Nuclei (CCN) number concentration data from the University of California - Riverside Droplet Measurement Technologies continuous flow CCN instrument that was deployed on the NSF NCAR C-130 aircraft for the CAESAR campaign.
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- Award ID(s):
- 2412409
- PAR ID:
- 10586746
- Publisher / Repository:
- UCAR/NCAR - Earth Observing Laboratory
- Date Published:
- Subject(s) / Keyword(s):
- Cloud Condensation Nuclei
- Format(s):
- Medium: X Size: 35 data files; 2 ancillary/documentation files; 41 MiB Other: CSV: Comma Separated Value (text/csv)
- Size(s):
- 35 data files 2 ancillary/documentation files 41 MiB
- Location:
- (East Bound Longitude: 24.00000 ; North Bound Latitude: 82.00000 ; South Bound Latitude: 66.00000 ; West Bound Longitude: -14.00000 )
- Right(s):
- These data are available to be used subject to the University Corporation for Atmospheric Research ("UCAR") terms and conditions.
- Institution:
- University Corporation For Atmospheric Research UCARNational Center For Atmospheric Research NCAREarth Observing Laboratory EOLData Managment And Services DMS
- Sponsoring Org:
- National Science Foundation
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