摘要：Electrification of atmospheric dust influences the coagulation, wet removal and fall speeds
of dust particles. Alignment of dust particles can also occur in fair weather atmospheric
electrical conditions if the particles are charged. However, very few electrical measurements
made in elevated dust layers exist. Balloon-borne charge and particle instrumentation have
been used to investigate the electrical properties of elevated Saharan dust layers. Soundings
from the Cape Verde Islands, which experience frequent Saharan dust outbreaks,
intercepted several dust layers. Two balloon soundings during summer 2009 detected dust
particles in layers up to 4 km altitude. Simultaneous electrical measurements showed
charge inside the dust layers, with a maximum measured charge density of 25 pC m − 3, sufficient to influence wet removal processes.
