Very low frequency radio observations of lightning discharges

The AARDDVARK/WWLLN Very Low Frequency (VLF) Radio Sensor was installed at Arrival Heights from 10-15 December 2008 by Dr Craig J. Rodger and Dr. James Brundell as part of Antarctica New Zealand Event K069a. The sensor measures the magnetic field in the Very Low Frequency radio range (~500 Hz-50 kHz), and passes it to a PC which processes the data for the experiments. The primary experiment is the AARDDVARK observations. The secondary experiment, WWLLN, uses exactly the same VLF feed but processes it to detect the radio-wave pulses from lightning. WWLLN observations are sent to a central processing computer to determine the time and location of lightning pulses all over the globe. The World Wide Lightning Location Network (WWLLN) is an experimental Very Low Frequency (VLF) network of sensors being developed through collaborations with research institutions across the globe. The network exploits the considerable electromagnetic power radiated by lightning as "sferics" present in the VLF band. By combining radio-pulse observations from at least 5 stations, the WWLLN central processing computers can determine the location of the original lightning discharge. As the radio-pulse observations are immediately sent back across the internet to the central processing computers locations are generated within ~10 s of the discharge, and thus near real time. There are currently 33 active VLF receiving stations operating in the VLF World-Wide Lightning Location Network as of December 2008, including the "Scott Base" measurements made at Arrival Heights. WWLLN observations are continuously transmitted to one of the WWLLN primary servers, in this case flash.ess.washington.edu at the University of Washington, Seattle, USA.