摘要：The April–May 2010 explosive eruption of the Eyjafjallajökull volcano in Iceland produced a
tephra plume extending to an altitude of over 9 km. During many, but not all, of the
periods of significant volcanic activity the plume was sufficiently electrified to generate
lightning. This lightning was located by the UK Met Office long-range lightning location
network (ATDnet), operating in the very low frequency radio spectrum. An approximately
linear relationship between hourly lightning count rate and radar-derived plume
height was found. A minimum plume height for lightning generation of sufficient
strength to be detected by ATDnet was shown to be 5 km above sea level. It is not
clear why some plumes exceeding 5 km did not produce lightning detected by
ATDnet, although ambient atmospheric conditions may be an important factor.
