HR: 1340h
AN: AE33A-0193    [Abstracts]
TI: Real Time Display of New Mexico Tech Lighning Mapping Array Data
AU: * Rison, W
EM: rison@nmt.edu
AF: New Mexico Tech, Langmuir Laboratory, Socorro, NM 87801 United States
AU: Hamlin, T
EM: thamlin@nmt.edu
AF: New Mexico Tech, Langmuir Laboratory, Socorro, NM 87801 United States
AU: Edens, H
EM: edens@nmt.edu
AF: New Mexico Tech, Langmuir Laboratory, Socorro, NM 87801 United States
AU: Krehbiel, P
EM: krehbiel@ibis.nmt.edu
AF: New Mexico Tech, Langmuir Laboratory, Socorro, NM 87801 United States
AU: Hunyady, S
EM: hunyady@kestrel.nmt.edu
AF: New Mexico Tech, Langmuir Laboratory, Socorro, NM 87801 United States
AB: The New Mexico Tech Lightning Mapping Array (LMA) generates highly detailed three-dimensional images of lightning discharges over an area of about 150~km from the array center. A typical LMA consists of twelve VHF receivers distributed over an area about 80~km in diameter. Each receiver determines the amplitude and time of the highest VHF pulse in each 80~$\mu$s window -- those signals whose amplitudes exceed a noise-floor threshold are recorded to a local hard drive. During an active thunderstorm, data rates for each receiver are as high as 750 KB/s. With increases in computing power and wireless data speed, it is now possible to transmit and process a sufficient volume of data from the VHF receivers that images with adequate detail for real-time uses can be generated. There are currently three LMAs which have real-time displays which are accessible over the Internet. NASA has developed their own display for their North Alabama LMA$^1$, which has been available for the past several years. During the spring and summer of 2004 we developed real-time displays for the NSSL/Oklahoma University LMA$^2$ and for the NMT compact LMA installed at Langmuir Laboratory$^3$. A display for a fourth system, currently being installed at White Sands Missile Range in southern New Mexico, should be on-line by the summer of 2005. The eleven VHF receiving stations of the Oklahoma LMA are connected to a central processing computer over IEEE~802.11b wireless data links. Severn receivers are daisy-chained through one link and four stations are daisy-chained through a second link. Data rates are too high to allow transmission of the full data over the daisy-chained links, so the data transmitted by each station is reduced such that only the highest peak in a 400~$\mu$s window is transmitted. Each station sends its data to the central site in one-minute packets. After data from a sufficient number of stations (a minimum of six) have been received by the processing computer, the data is processed to generate RF source locations. A source location is generate about two to three minutes after the parent event. The location data is sent to the display computer, where plots are generated and posted on a web site. Plots of ten minutes of data and of one hour of data are available. Data are displayed in terms of the density of RF sources per unit area. The compact LMA at Langmuir Lab (see Edens et al, this conference), in the Magdalena Mountains of central New Mexico, has eight stations distributed over an area of about 4~km in diameter, 2~km above the surrounding plains. The array detects noise sources (e.g., corona from power lines) on the plains surrounding the mountains. Because of the compactness of the array, these localized sources appear on the plots as a line extending radially away from the center of the array through the sources. During periods of no lightning activity, the display often shows several radial lines from such localized noise sources. $^1$http://branch.nsstc.nasa.gov/cgi-bin/LMA.pl $^2$http://lightning.nmt.edu/oklma $^3$http://lightning.nmt.edu/ll_lma
DE: 3324 Lightning
DE: 3360 Remote sensing
DE: 3394 Instruments and techniques
DE: 3304 Atmospheric electricity
SC: Atmospheric and Space Electricity [AE]
MN: 2004 AGU Fall Meeting