Open AccessA balloon‐borne cloud condensation nuclei counter
Author(s) -
Delene David J.,
Deshler Terry,
Wechsler Perry,
Vali Gabor A.
Publication year - 1998
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/98jd00053
Subject(s) - cloud condensation nuclei , supersaturation , aerosol , condensation , atmospheric sciences , materials science , environmental science , thermal diffusivity , physics , meteorology , thermodynamics
A balloon‐borne instrument was constructed for observations of vertical profiles of cloud condensation nucleus (CCN) concentrations, active at 1% supersaturation. Droplet concentration in the static thermal‐gradient diffusion chamber is deduced from the amount of scattered laser light detected by a photodetector. The photodetector is calibrated using a video camera and computer system to count the number of droplets produced from NaCl aerosol. Preliminary data are available from nine early morning profiles obtained at Laramie, Wyoming, between June 1995 and January 1997. To complement the CCN measurements, instruments that measure condensation nuclei (CN) and aerosols with diameter greater than 0.30 μm (D 0.3 ) were also included on the balloon package. CCN concentrations exhibited a general decrease from the surface to the top of the boundary layers, were generally uniform through well‐mixed layers, and show variability above well‐mixed layers. In general, the structure of the CCN profile appears to be closely related to the structure in the CN and D 0.3 profiles. Summer profiles generally have CCN concentration greater than 200 cm −3 up to 500 mbar, whereas winter profiles are less than 200 cm −3 at all levels.