Lightning, a sudden electrostatic discharge accompanied with thunder,
can be somewhat intimidating but amazing at the same time. It usually
occurs in strong cumulonimbus clouds where convection develops vigorously,
therefore often accompanied by strong gusts and heavy rains, sometimes
accompanied by hailstones and tornadoes.
Lightning is the phenomenon of discharge in the atmosphere, mostly
occurring in cumulonimbus clouds. The cumulonimbus will constantly
move with the change of temperature and air flow. When the friction
caused by the motion generates electricity, charged clouds layer will
form with some clouds positively charged and others negatively charged.
Besides, electrostatic often oppositely charges the buildings, trees
and many other things under the clouds. As the charge accumulates, the
voltage of the thundercloud rises. When the thundercloud with opposite
charge gets close to the projection on the ground to a certain extent,
the electric field intensity is over 25-30kv/cm, resulting in an intense
discharge and a bright flash. Because of the high temperature that is up
to 2000℃, the air intensely expands, and therewith the roar of the
explosion. That is the thunder and lightening flash. The size, frequency
and movement of lightening depends on the landform, meteorological
condition and latitude of different areas. Basically there is more
lightening on mountain lands than plains. Also, the higher one building
is, the greater the chance is for it to get stricken by lightening.