HR: 1330h
AN: AE22A-1110    [PDF]
TI: Effects of a Longer Detection Window in VHF Time-of-Arrival Lightning Detection Systems
AU: * Murphy, M
EM: martin.murphy@vaisala.com
AF: Vaisala Inc., 2705 E. Medina Rd., Tucson, AZ 85706 United States
AU: Holle, R
EM: ron.holle@vaisala.com
AF: Vaisala Inc., 2705 E. Medina Rd., Tucson, AZ 85706 United States
AU: Demetriades, N
EM: nick.demetriades@vaisala.com
AF: Vaisala Inc., 2705 E. Medina Rd., Tucson, AZ 85706 United States
AB: Lightning detection systems that operate by measuring the times of arrival (TOA) of short bursts of radiation at VHF can produce huge volumes of data. The first automated system of this kind, the NASA Kennedy Space Center LDAR network, is capable of producing one detection every 100 usec from each of seven sensors (Lennon and Maier, 1991), where each detection consists of the time and amplitude of the highest-amplitude peak observed within the 100 usec window. More modern systems have been shown to produce very detailed information with one detection every 10 usec (Rison {\it et al.}, 2001). Operating such systems in real time, however, can become expensive because of the large data communications rates required. One solution to this problem is to use a longer detection window, say 500 usec. In principle, this has little or no effect on the flash detection efficiency because each flash typically produces a very large number of these VHF bursts (known as sources). By simply taking the largest-amplitude peak from every 500-usec interval instead of every 100-usec interval, we should detect the largest 20{%} of the sources that would have been detected using the 100-usec window. However, questions remain about the exact effect of a longer detection window on the source detection efficiency with distance from the network, its effects on how well flashes are represented in space, and how well the reduced information represents the parent thunderstorm. The latter issue is relevant for automated location and tracking of thunderstorm cells using data from VHF TOA lightning detection networks, as well as for understanding relationships between lightning and severe weather. References Lennon, C.L. and L.M. Maier, Lightning mapping system. {\it Proceedings, Intl. Aerospace and Ground Conf. on Lightning and Static Elec.}, Cocoa Beach, Fla., NASA Conf. Pub. 3106, vol. II, pp. 89-1 - 89-10, 1991. Rison, W., P. Krehbiel, R. Thomas, T. Hamlin, J. Harlin, High time resolution lightning mapping observations of a small thunderstorm during STEPS. {\it Eos Trans. AGU}, {\it 82} (47), Fall Meet. Suppl., Abstract AE12A-83, 2001.
DE: 3304 Atmospheric electricity
DE: 3324 Lightning
DE: 3360 Remote sensing
DE: 3394 Instruments and techniques
SC: Atmospheric and Space Electricity [AE]
MN: 2003 Fall Meeting