|Lightning in the atmosphere develops due to charging processes within convective clouds. Basically one can discriminate between ground flashes, exchanging charges between the cloud and the ground (CG - cloud to ground), and cloud flashes (IC - intra cloud) not making ground contact. During the discharge process electromagnetic waves are emited from the lightning channel. LINET detects the VLF/LF part of the spectrum, both, for CG and IC flashes. |
Lightning research and monitoring are essential for:
- general warnings of hazardeous weather by detection and nowcasting of lightning in thunderstorms including air traffic and airport safety
- climate impacts of lightning produced nitrogen oxides as compared to ground sources or air traffic
- validation of space-borne lightning measurements
LINET is a particularly sensitive network working at VLF/LF range with 3D capability. The efficiency of the system allows for unprecedented low-amplitude detection power. Below ~10 kA an order of magnitude more signals are identified compared to conventional networks, even for equal baseline. Since abundant IC events are located an effective discrimination against CG is required. The chosen solution consists in the employment of a new 3D-technique which is independent of any adjustable parameters. Preferentially, the TOA (time of arrival) method is used for locating the horizontal and vertical position of lightning strikes.
The system has been developed by LMU during recent years. A 6-station network is operated by DLR in cooperation with LMU during special observation periods like field campaigns (TROCCINOX, SCOUT-O3, AMMA, COPS, Munich high resolution network). For example, POLDIRAD radar measurements have shown a strong dominance of IC flashes during some phases of supercell development.