Lightning is a giant electrical spark and is caused
by the separation of electrical charge in a thunderstorm. The
mechanism of charge separation is still poorly understood but
there now seems little doubt that ice particle collisions are
involved and the conditions favourable to ice particle collisions
are strong updrafts which invigorate a thunderstorm's ice factory.
Charge separation by particle collisions occurs until the voltage
difference in the cloud reaches 10 to 100 mega volts and the local
electric field reaches several hundred kilovolts per meter. The
latter field is the approximate dielectric strength of the thundercloud
medium and its attainment is required to initiate lionization,
the initial stage of the large spark that is lightning.
Storm Detection information.
All kinds of lightning (cloud-to-cloud, cloud-to-ground,
positive, and negative strokes) are detected by my Boltek detector
and with the use of Nexstorm™ to perform the calculations
this information gets plotted on a map.. Additionally, two special
stroke types, the compact intercloud discharge and the leader
are detected from nearby storms as well.
How far away can it detect lightning depends on
the intensity of the storm and the kind of terrain between my
detector and the storm. Also, I get better "reception"
at night. Stronger storms can be detected further away and flat
terrain between me and the storm gives me a better chance of "seeing"
the storm. Generally, storms within 400 miles will be detected
easily. Intense storms have been detected over 1000 miles away.
When the Lightning Detector detects lightning stokes
it may take a while to get the position correct, this is due to
it recalculating each time. The more strokes the better the position.
Some storms will be plotted in the wrong position. The best way
to use this data is to look at other sites also plotting the information
and average out the data. I will be working with some other users
of Boltek units to see if we can produce better storm data and
in the future combine the data on to this site and mirror on other
sites.
The information is
provided for general interest.
It cannot be used for the protection
of life or property.
Cloud to ground lightning
Cloud-to-ground lightning is the most spectacular
lightning. It is the lightning bolt we see reaching from the sky
to the ground forming a bright, usually forked bolt of light.
The ground is the most conductive object that will release the
most energy. This form usually occurs from the base of a negatively
charged cloud. Sometimes there is a rarer form that happens from
the the positive charge in the top of the cloud to the negative
charge on the ground known as a positive flash. Only about 20
percent of all lightning reaches the ground. Over the entire Earth
there are over 100 strikes every second.
Cloud-to-ground lightning is the most damaging and
dangerous form of lightning. The great majority of ground flashes
are negative, but the most powerful and most dangerous are the
positive ground flashes that can also produce sprites in the mesosphere.
Positive flashes occur in the decaying phases of large thunderstorms
and in the very active stages of severe storms. Most cloud-to-ground
lightning strikes come from the negatively charged bottom of the
cloud traveling to the positively charged ground below.
Some meteorologists believe that positive lightning
strikes indicate storms that are more likely to spin out tornadoes.
Intra cloud lightning
The most common type of lightning, called intra cloud
lightning, strikes between positive and negative areas in the
same cloud. The bolt is not usually visible, but rather appears
like a broad flash in the sky.
Intra cloud lightning is far more prevalent than
cloud-to-ground lightning, and the mean peak currents in intra
cloud lightning tend to be smaller. Intra cloud flashes that leave
cloud base and approach ground, but do not reach ground, are called
air discharges. Intra cloud lightning that leaves cloud top and
heads upwards are sometimes referred to as cloud-to-ionosphere
flashes.
In the active stages of severe storms, intra cloud
flashes can outnumber ground flashes by 10-100 to one.
Inter cloud lightning
Intra cloud flashes that bridge two thunderstorms are called intercloud
flashes. This less common lightning strike occurs between oppositely
charged areas of separate clouds. Known as intercloud lightning,
the strike passes through clear air and provides a stunning bolt
of light. Intercloud lightning poses a particular hazard to airplanes
in flight because it passes through the clear air between clouds.
Key to Live Lightning page
+ CG Positive cloud to ground strike
- CG Negative cloud to ground strike
+ IC Positive in cloud or intracloud strike
- IC Negative in cloud or intracloud strike
Its also worth noting that I may clear off strike
data during some storms. This is because I am using the system
and removing clutter.
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