关键词:
Electrification
Comment
Downdrafts
evaporation
SEPARATION PROCESSES
AIR DRYING
thunderstorms
fallout particulates
vertical motion
Charge separation
Ions
摘要:
The article by Saundere (1993) seems to follow a pattern being repeated with some, if infrequent, regularity in what seems to be an attempt to discourage critical discussion of charged ice theories of thunderstorm electrification. The current theoriesseem to make little attempt to incorporate any dynamically realistic air motion structure within the cloud. The simplified picture that is usually used assumes a smooth updraft, in which the charged particles settle downward and hence produce bulk charge separation without any consideration of the violent updrafts and downdrafts that dilute such clouds with dry air from above, and result in their ultimate dissipation by dilution and evaporation. It is hard to see how such vigorous mixing can fail to mix the precipitation particles throughout the cloud and thus neutralize the net charge separation by mixing positive and negative particles together. On the other hand, the structure of the downdrafts has been used to show how ionic-charge separation processes can directly result from the vertical motion of the diluting turbules that also carry the charge (Wagner and Telford 1981).