Preprints
https://doi.org/10.5194/acpd-6-4879-2006
https://doi.org/10.5194/acpd-6-4879-2006
19 Jun 2006
 | 19 Jun 2006
Status: this preprint was under review for the journal ACP. A revision for further review has not been submitted.

Technical note: A method for measuring size-resolved CCN in the atmosphere

G. P. Frank, U. Dusek, and M. O. Andreae

Abstract. We present a method to investigate cloud condensation nuclei (CCN) concentrations and activation efficiencies as a function of two independent variables, aerosol particle size and water vapor supersaturation. To date, most ambient CCN measurements have been made as the integral (total) CCN concentration as a function of water vapor supersaturation only. However, since CCN properties of aerosol particles are strongly dependent on particle size, as well as on chemical composition, which commonly varies with particle size, more detailed measurements can provide additional important information about the CCN activation. With size-resolved measurements, the effect of particle size on CCN activity can be kept constant, which makes it possible to directly assess the influence of particle chemistry.

The instrumental set-up consists of a differential mobility analyzer (DMA) to select particles of a known size, within a narrow size range. A condensation nuclei (CN) counter (condensation particle counter, CPC) is used to count the total number of particles in that size range, and a CCN counter is used to count the number of CCN as a function of supersaturation, in that same size range. The activation efficiency, expressed as CCN/CN ratios, can thus directly be calculated as a function of particle size and supersaturation. We present examples of the application of this technique, using salt and smoke aerosols produced in the laboratory as well as ambient aerosols.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
G. P. Frank, U. Dusek, and M. O. Andreae
 
Status: closed (peer review stopped)
Status: closed (peer review stopped)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
 
Status: closed (peer review stopped)
Status: closed (peer review stopped)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
G. P. Frank, U. Dusek, and M. O. Andreae
G. P. Frank, U. Dusek, and M. O. Andreae

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