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Experimental determination of layer cloud edge charging from cosmic ray ionisation
Author(s) -
Nicoll K. A.,
Harrison R. G.
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl043605
Subject(s) - cosmic ray , ion , cloud computing , atmospheric electricity , aerosol , cloud albedo , boundary layer , electric charge , space charge , cloud physics , computational physics , physics , atmospheric sciences , environmental science , meteorology , cloud cover , electric field , astrophysics , mechanics , electron , operating system , quantum mechanics , computer science
The cloud‐air transition zone at stratiform cloud edges is an electrically active region where droplet charging has been predicted. Cloud edge droplet charging is expected from vertical flow of cosmic ray generated atmospheric ions in the global electric circuit. Experimental confirmation of stratiform cloud edge electrification is presented here, through charge and droplet measurements made within an extensive layer of supercooled stratiform cloud, using a specially designed electrostatic sensor. Negative space charge up to 35 pC m −3 was found in a thin (<100 m) layer at the lower cloud boundary associated with the clear air‐cloud conductivity gradient, agreeing closely with space charge predicted from the measured droplet concentration using ion‐aerosol theory. Such charge levels carried by droplets are sufficient to influence collision processes between cloud droplets.