WWLLN
World Wide Lightning
Location Network (wwlln.net)
SYSTEM MESSAGE:
WWLLN is fully functional with several new stations being installed, and a few old ones being
repaired. Our newest station is hosted by the Center for Geophysical Research
(CIGEFI), University of Costa Rica.
Contact Prof. Holzworth at bobholz@washington.edu , Director of WWLLN, with any questions you may have.
Users of these pages, please click to let us know of
your use and suggestions. (RHH
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(Notes: cloud data thanks to National Weather Service/Aviation Weather Center; blue overlay dots are WWLLN Lightning; Red circles are WWLLN receivers; Red line is the terminator)
With our network of sferic sensors we are producing regular maps of lightning
activity over the entire Earth. Our map showing the entire world uses coloured
spots to indicate lightning strokes (red stars inside an open circle are active
WWLLN lightning sensor locations). Click on the map to expand.
Prof
Robert Holzworth of the University of Washington produced these
data with the cooperation of the universities and institutes which host the
stations as listed below.
The concept of the toga - time of group arrival - used in the location of lightning was published in a paper (see Publications link below)
(
Wideband VLF
spectrograms below show lightning-generated sferics (vertical lines) from
our lightning sensors and narrowband signals (horizontal lines) from VLF
transmitters. Each spectrogram spans 15s in time (horizontal axis) and 24kHz in
frequency (vertical axis) All start at precisely the same time at exactly 0,
10, 20, ... min past each hour. Click on any thumbnail below to expand it to
full size (or click on its caption to open it on a new page).
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We currently have over 25 sensors logging sferic activity in the VLF band,
listed below in the order of their establishment:
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University of Otago/Te Whare Wānanga o Otāgo ( |
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Massachusetts Institute of Technology |
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INPE (Brazilian National Institute for Space Research) |
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University of the South Pacific ( |
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Mexico |
Universidad Nacional Autonoma de Mexico |
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Universite de la Polynesie Francaise |
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Tel Aviv |
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Centre for Earth Science Studies ( |
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Huancayo |
Instituto Geofisico del Peru |
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Cordoba |
Universidad Nacional de Cordoba ( |
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Sodankylä Geophysical Observatorya, Sodankylä, |
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Rothera |
British Antarctic Survey |
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Cold and Arid Regions Environmental and Engineering
Research Insitute, |
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Ascension Is. |
British Geological Survey and BAS |
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Kingston and Davis |
Australian Antarctic Division |
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Hermanus |
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Boulder |
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UCLA |
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Costa Rica |
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How it works
We
welcome offers of hosting a new WWLLN sensor to add to the list above. All
hosts receive all the world-wide data for their own research on monthly CDs. In
return, each host provides the computer and meets any local expenses like
power, Internet, and maintenance. However, do not think that a sensor on
your own campus is going to give you lightning location data on its own. Only
the whole network does that.
Each lightning stroke location requires the time of group arrival (TOGA) from a
least 4 WWLLN sensors. These sensors may be several thousand km distant from
the stroke. In fact, there is some evidence to suggest that the sensors close
to the lightning stroke are unhelpful. The geographical arrangement
of the sensors is important: a lightning stroke which is enclosed by sensors is
much more accurately located than one which is not so enclosed. Clearly a
uniform spacing of sensors around the Earth is the ideal. Since the Earth is
round, there are no edges: every lightning stroke is surrounded by sensors, but
not necessarily by the sensors which sense it. Currently (2004) only about 50%
of strokes detected by one sensor are detected by 4 or more. These
strokes are presumably the stronger ones.
To cover the whole world by sensors spaced uniformly about 1000 km apart would
require roughly 500 sensors. If spaced 3000 km apart, we would need
“only” around 50 sensors. We already have about half this number:
mainly in developed countries but not enough in less-developed countries, many
of which are in the tropics where lightning is most prevalent.
Direct Weather comparison
WWLLN map with superimposed cloud viewed by satellite
(updated periodically)
(also see other views Americas
or Europe/Africa
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(Thanks to National Weather Service/Aviation Weather Center for images of cloud
cover).
More information
More
information on the World Wide Lightning Location network (WWLLN) is
available from our publication list:
WWLLN Data available
WWLLN Monthly CDs containing all stroke locations over the whole
world for 1 month. These are mailed to subscribers within 5 days after the end
of each month. Back-issues are available as far back as August 2003. Our site
hosts receive a free subscription.
WWLLN Data Files by Internet for recent lightning events (in the last
six weeks) are available on subscription for any specified geographical area
and time window. We can tailor this service to your data requirements: weekly,
daily, hourly, real-time for example.
Contacts
for new sensor locations or WWLLN
data subscriptions and back-issues:
Prof Robert Holzworth, Earth and Space Sciences,
bobholz@washington.edu
Webpage maintained by:
Craig J Rodger (University of Otago)
Robert Holzworth (University of Washington)
Lightning image thanks to photolib.noaa.gov
Web editing:
Bob Holzworth (bobholz@washington.edu)