Ask A Scientist Weather Archive

name         Sophie
status       other
grade        other
location     N/A

Question -   How many times does the lighting strike the earth in one day?
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Dear Sophie-

   When you include observations of weather over the whole earth, you get
some pretty amazing numbers.  Here are a couple-

   Number of thunderstorms occurring at any given time:  2000

   Number of lightning strikes over the earth per second:  100

(The above numbers from this web site:
http://www.lightningstalker.com/weather/lightningstalker/more.html)

Expanding the lightning numbers...  100 per second equals 6000 strikes per
minute
                                                    6000 per minute equals
360,000 per hour
                                                    360,000 per hour equals
8,640,000 per day

Wendell Bechtold, meteorologist
Forecaster, National Weather Service
Weather Service Office, St. Louis, MO
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Sophie,

A number of studies have been done using lightning detection networks
located in some countries and using a couple of satellites that have
optical detectors designed to recognize lightning flashes.  The most recent
data suggests that the long used statistic of around 100 flashes per second
globally is close to being correct, of which 80% are in-cloud flashes and 20%
are cloud-to-ground flashes.

This gives us approximately 20 flashes to the ground per second globally and
therefore 1,728,000 flashes to the ground per day.  This seems like a huge
number, but it is necessary to maintain an electrical balance between
the Earth's surface and the atmosphere.


David R. Cook
Atmospheric Physics and Chemistry Section
Environmental Research Division
Argonne National Laboratory
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This is not an easy question to answer because the average number of
strikes varies with location, season, and many other variables. However,
the web site:

http://www.lightningsafety.com/nlsi_info/lightningmaps/worldlightning.html

shows a global distribution map. This can give you an approximate
distribution. Another interesting site is:

http://www.exploratorium.edu/ronh/weather/weather.html

Vince Calder
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