Research Tools: Oklahoma Lightning Mapping Array

The National Severe Storms Laboratory and the University of Oklahoma jointly operate the Oklahoma Lightning Mapping Array (OKLMA) to map the time and location of lightning channel segments within clouds. To do this, the system measures the time at which a signal radiated by a lightning channel in a VHF band (the former television channel 3 band) arrives at each station in the OKLMA network. The times are transmitted to a central station, which computes the time, latitude, longitude, and height of the segment that radiated the signal. Since 2003, there have been 10-11 stations in central Oklahoma. In April 2012, seven additional stations were added in southwest Oklahoma. Thousands of points can be mapped for an individual lightning flash, to reveal its location and the development of its structure.

NSSL scientists hope to use the data from OKLMA to learn more about how storms produce intra-cloud and cloud-to-ground flashes and how each type is related to tornadoes and other severe weather. Better lightning mapping techniques show that some supercell thunderstorms have “lightning holes” where updrafts are located and precipitation is scarce. If these holes form, as suspected, just before a storm becomes severe, this information could alert forecasters to developing severe conditions.

The OKLMA was an integral part of the 2003 and 2004 Thunderstorm Electrification and Lightning Experiment (TELEX) and the Deep Convective Clouds and Chemistry (DC3) field project.

OKLMA Site

OKLMA site north of Chickasha, OK. The VHF antenna on the right receives signals in the channel 3 television band. This signal is processed by electronics in the small plastic building on the left of the picture to determine the time at which the signal is received to within less than a millionth of a second. This time and information about the signal is then sent back to a central processor in Norman via the communication antenna beside the plastic building. The central processor records the information from all stations and, in real time, uses the times from several antennas to determine the three-dimensional location at which a lightning channel segment radiated the signal.

These data are being used with radar and other storm measurements in scientific studies to help understand how thunderstorms produce lightning and to develop ways of using lightning mapping data to warn and forecast of weather hazards.

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OKLMA site north of Chickasha, OK. The VHF antenna on the right receives signals in the channel 3 television band. This signal is processed by electronics in the small plastic building on the left of the picture to determine the time at which the signal is received to within less than a millionth of a second. This time and information about the signal is then sent back to a central processor in Norman via the communication antenna beside the plastic building. The central processor records the information from all stations and, in real time, uses the times from several antennas to determine the three-dimensional location at which a lightning channel segment radiated the signal.

These data are being used with radar and other storm measurements in scientific studies to help understand how thunderstorms produce lightning and to develop ways of using lightning mapping data to warn and forecast of weather hazards.