HR: 1340h
AN: AE33A-0180    [Abstracts]
TI: Locating Lightning With the New LANL Sferic Array
AU: * Harlin, J D
EM: harlin@lanl.gov
AF: Space and Remote Sensing Sciences, Los Alamos National Laboratory, ISR-2, MS D436, Los Alamos, NM 87545 United States
AU: Shao, X
EM: xshao@lanl.gov
AF: Space and Remote Sensing Sciences, Los Alamos National Laboratory, ISR-2, MS D436, Los Alamos, NM 87545 United States
AU: Stanley, M
EM: stanleym@lanl.gov
AF: Space and Remote Sensing Sciences, Los Alamos National Laboratory, ISR-2, MS D436, Los Alamos, NM 87545 United States
AB: In the spring of 2004 Los Alamos National Laboratory deployed a new electric field change array (EDOTX) in north central Florida. Six of the eight stations are placed inside an area of about 150 km in diameter, producing high resolution locations of events within the network. The two distant stations allow for a wider field of coverage. The 1-500 kHz signal is digitized at 2 Mhz and the typical record length is 1 millisecond, with some events producing multiple back to back records. The previous array had record lengths of 8 milliseconds on average, and was deployed over a much larger area. The old method for 2-D geo-location was to cross-correlate the waveforms, get one time per record, and then use three or more stations to locate that event using a downhill simplex method. The new method takes a different approach. First the data is converted to power using a Hilbert transform, then individual peaks are selected and matched among the stations. Depending upon the complexity of the waveform and number of back to back records this method can produce multiple sets of times for a given event. Then for each set of times, if there are at least four stations, we obtain an initial guess for the location by a linear inversion, which is then passed to a least squares routine. The end result is more 2-D geo-located sources, each with an error measure, and the processing time is much faster compared to the old method. With this system it is possible to resolve separate cells within the storms, and even study the channel development of individual flashes.
DE: 3324 Lightning
DE: 3360 Remote sensing
DE: 3304 Atmospheric electricity
SC: Atmospheric and Space Electricity [AE]
MN: 2004 AGU Fall Meeting