Positive CG (+CG) flashes effectively bring positive charge to ground (or negative charge up) and almost always have only a single return stroke.
CG flashes that bring negative charge from the cloud to ground (“negative CG” or “-CG”) can have multiple return strokes, which can sometimes be seen visually as a flickering of the channel to ground. Flashes outside of the network have larger location errors and may not even be detected.Įach system may detect more than one stroke (in-cloud or return) for a single lightning flash. Location accuracy is best when lightning occurs within a network of stations.
Radio signals are detected by multiple stations (at least 3) are used to determine the location of the stroke by a time-of-arrival technique. Since there are many other sources of radio noise, the systems have to first identify which bursts are likely to be caused by lightning. CG return strokes usually have larger currents that make stronger signals that are easier to detect. A “stroke” can be a fast current within the cloud, or a “return stroke” in a channel to ground. These two systems work by detecting radio waves (sferics) emitted by fast electric currents (strokes) in lightning channels. Severe Weather 101 Lightning Detection Lightning Detection NetworksĬurrently, cloud-to-ground (CG) and intra-cloud (IC) lightning flashes are detected and mapped in real-time by two different networks in the United States-the National Lightning Detection Network (NLDN), a system owned and operated by Vaisala Inc, and the Earth Networks Total Lightning Network.
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