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Charge transfer during Crystal‐Graupel Collisions for two different cloud droplet size distributions
Author(s) -
Avila Eldo A.,
Pereyra Rodolfo G.
Publication year - 2000
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 - 10.1029/2000gl012302
Subject(s) - graupel , ice crystals , liquid water content , range (aeronautics) , materials science , environmental science , spectral line , meteorology , physics , cloud computing , astronomy , computer science , composite material , operating system
Laboratory experiments of graupel charging during ice crystal collisions reveal a charge sign dependence on temperature, liquid water concentration as well as the size distribution of the cloud droplets used for riming. The measurements were performed with an impact velocity of 8.5 m s −1 , the ambient temperature was varied in the range −5 to −30°C and the effective water content up to 4 g m −3 . Charge diagrams of the sign of the electric current on the graupel as a function of the ambient temperature (T a ) and the effective liquid water content (EW) for each of the two cloud droplet spectra used are presented. The results indicate that broadening the droplet spectrum leads to negative graupel charging and the implications of these findings to thunderstorm electrification are discussed.