HR: 1330h
AN: AE22A-1108    [PDF]
TI: New Mexico Tech Lightning Mapping Array: Real-Time System Monitoring and Data Display
AU: * Rison, W
EM: rison@nmt.edu
AF: Langmuir Laboratory New Mexico Tech, 801 Leroy Place, Socorro, NM 87801 United States
AU: Miller, S
EM: slmiller@nmt.edu
AF: Langmuir Laboratory New Mexico Tech, 801 Leroy Place, Socorro, NM 87801 United States
AU: Hunyday, S
EM: hunyday@kestrel.nmt.edu
AF: Langmuir Laboratory New Mexico Tech, 801 Leroy Place, Socorro, NM 87801 United States
AB: The New Mexico Tech Lightning Mapping Array (LMA) is a VHF time-of-arrival (TOA) lightning mapping system. In a typical deployment it consists of ten to fifteen VHF receivers distributed over a geographical area of about 90~km in diameter. It was designed to be relatively inexpensive by recording TOA data locally at the remote stations, using GPS timing to determining the time of arrival of impulsive VHF radiation from lightning with about 40~ns accuracy. The TOA data is collected after storms by driving to the remote stations and collecting the data on magnetic media for post-processing. During its design phase cost-effective communications links with a high enough bandwidth for real-time processing and display were not available. We initially used low-speed (9600 baud) wireless links to the remote stations for system monitoring and control. With recent advances in wireless communications, it is now cost-effective to implement real-time data processing and display. Each LMA station typically determines the time of the strongest source of VHF radiation in an 80~$\mu$s window, for up to 12,500 TOA sources per second. At its full data rate it can take tens of minutes to process a minute of LMA data. Using software to decrease the data rate so that the TOA data is windowed over a longer interval (say, 400~$\mu$s), it is possible to process this decimated data in real time using an inexpensive PC. While the images generated using this decimated data are not as detailed as post-processed images generated using the full TOA data, they are sufficiently detailed for most operational uses. Using relatively inexpensive IEEE 802.11b wireless Ethernet cards, we can achieve data rates sufficiently high so that we can transmit this decimated data from remote stations to a central location. During the summer of 2003 we have developed a real-time monitoring and data processing/display system, somewhat similar to the monitoring and display system for the North Alabama LMA$^1$. We use software developed in-house for data transmission and processing, and use the NCAR Command Language (NCL$^2$) for generating graphical images. Over the next few months we plan to install this monitoring/display software on the NMT LMA in central New Mexico, and the NSSL LMA in central Oklahoma.\\[1ex] \noindent $^1$\verb+http://branch.nsstc.nasa.gov/cgi-bin/LMA.pl+ \\ \noindent $^2$\verb+http://ngwww.ucar.edu/ncl/index.html+
DE: 3324 Lightning
DE: 3337 Numerical modeling and data assimilation
DE: 3360 Remote sensing
DE: 3394 Instruments and techniques
SC: Atmospheric and Space Electricity [AE]
MN: 2003 Fall Meeting