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Aerosol removal and cloud collapse accelerated by supersaturation fluctuations in turbulence
Author(s) -
Chandrakar K. K.,
Cantrell W.,
Ciochetto D.,
Karki S.,
Kinney G.,
Shaw R. A.
Publication year - 2017
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 - 10.1002/2017gl072762
Subject(s) - supersaturation , aerosol , cloud computing , drizzle , turbulence , environmental science , liquid water content , atmospheric sciences , albedo (alchemy) , cloud physics , cloud albedo , meteorology , physics , cloud cover , precipitation , thermodynamics , computer science , operating system , art , performance art , art history
Prior observations have documented the process of cloud cleansing, through which cloudy, polluted air from a continent is slowly transformed into cloudy, clean air typical of a maritime environment. During that process, cloud albedo changes gradually, followed by a sudden reduction in cloud fraction and albedo as drizzle forms and convection changes from closed to open cellular. Experiments in a cloud chamber that generates a turbulent environment show a similar cloud cleansing process followed by rapid cloud collapse. Observations of (1) cloud droplet size distribution, (2) interstitial aerosol size distribution, (3) cloud droplet residual size distribution, and (4) water vapor supersaturation are all consistent with the hypothesis that turbulent fluctuations of supersaturation accelerate the cloud cleansing process and eventual cloud collapse. Decay of the interstitial aerosol concentration occurs slowly at first then more rapidly. The accelerated cleansing occurs when the cloud phase relaxation time exceeds the turbulence correlation time.