A network for real-time lightning impulse charge moment change measurements

In 2007, we developed and deployed a sensor network that provides near real-time measurements of impulse charge moment change (defined as that which occurs in the first 2 ms of a stroke) in most lightning strokes over the continental United States. This network, called the lightning Charge Moment Change Network (CMCN), combines lightning geolocation from Vaisala's U.S. National Lightning Detection Network (NLDN) with rapid processing of broadband low frequency (3 Hz to 30 kHz) magnetic field measurements at two sites, one near Duke University in North Carolina and one near Fort Collins, CO. We will describe the basic operation of the network, its value in identifying in near real-time (~5 minutes) storms and locations within storms that are producing high charge moment change lightning, and general measurement statistics from several years of near-continuous operation. The CMCN output have proven valuable in detecting those systems that are producing transient luminous events, especially sprites.