P1258755358qwDyZ

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Total Lightning Observations With New and
Improved Los Alamos Sferic Array (LASA)
  Xuan-Min Shao, Mark Stanley, Jeremiah
Harlin, Amy Regan, Morrie Pongratz, Mike
Stock Space and Remote Sensing Sciences Group,
ISR-2 Los Alamos National Laboratory
Southern Thunder Workshop , Ft. Worth, 07/25-27/05
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Florida LASA Eight stations deployed in April,
2004
Operated via Internet
Deployed April, 2004
Sensor on Roof
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GPS Block IIF V-GLASS (VHF Global Lightning And
Severe Storm Monitor)
MISSION Global VHF
Lightning and Total Electron Content (TEC)
Monitoring Lightning detection as proxy
for monitoring deep convection
An extension of an already-
scheduled DoD mission using existing
h/w and s/w
PLATFORM Platform GPS Constellation
(24 Block IIF/III satellites) Altitude
20,000 km Launches 2007-2011
SENSORS Type Broadband VHF
receivers Capability Event time, 3D location,
TEC Lightning/sec/sat 1 - 10 Coverage 1
gnd stat. (regional, real-time)
4 gnd stats. (global, real-time)

V-Sensor
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Samples of E-Field Changes
IC
CG
ELVES observed by ISUAL
Energetic -CG
-CG
8 ms
1 ms
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New processing algorithm allows each peak
detected and located (1) Convert E-field to
power, (2)detect power peaks, (3) match peaks
among stations, (4) time-tag matched peaks, (5)
locate peaks.
Match peaks among stations
Hilbert Transform
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Air mass, afternoon storms monotonically produce
3-4 time more ICs than CGs, and uniformly
produce NBs
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Frontal storms associated with variable IC/CG
ratios, depending on storm stages, and only
selectively produce NBs
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LASA vs. NEXRAD able to outline structures of
active storm cells. Can be used to now-cast
severe storms
Radar
EdotX
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2-D location accuracy, lt 0.5 km near the dense
array

• Located 8 of 13 triggered return strokes at Camp
  Blanding in 2004
• Peak currents 3.6-17.8 kA
• Location errors 20-156 m with an average 91 m.

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Detection efficiency A few kAs within 100km, 25
kA at 600 km. 2-5 more ICs than CGs within 100 km
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Daily trigger rate 106 107
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3-D capability for lightning near the dense
array Total of 724 in 4 minutes, 120 are return
strokes
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3-D observation of small cell Notice the source
height development. 498 pts in 50 min
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Great Plains Array deployed in April,
2005 Algorithms development underway
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LASA captured a handful lightning events that are
tightly associated with TGFs detected by RHESSI
satellite. All waveforms are similar but exotic.
No NB was found associated with TGF
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Measured attenuation agrees with simulation a
possible tool for soil conductivity and water
content mapping (meters deep into earth,
progress underway)
LB cutoff freq

• Spectrum ratios between inland and DAB stations.
• More attenuation at farther stations.
• Path to TPA more conductive than to GNV?

Blue PLK Green GNV Red TPA Black TLH
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Summary

• New LASA FLN operated continuously since April,
  2004
• Captures full waveforms without any trigger dead
  time
• Detects several to several tens events per flash
• Can readily distinguish ICs, CGs, and NBs
• 3-D capability for lightning near the dense
  array
• Great Plains Array started operation in April,
  2005
• Compared to other observations, e.g., TGF,
  Sprit.