ISRISRLos Alamos National LaboratoryTotal Lightning Observations With New and

ImprovedLos Alamos Sferic Array (LASA)

 

Xuan-Min Shao,

Mark Stanley, Jeremiah Harlin, Amy Regan, Morrie Pongratz, Mike Stock

Space and Remote Sensing Sciences Group, ISR-2Los Alamos National Laboratory

Southern Thunder Workshop , Ft. Worth, 07/25-27/05

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Florida LASA

Eight stations deployed in April, 2004

Deployed April, 2004

Operated viaInternet

Sensor onRoof

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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

PLATFORMPlatform: GPS Constellation (24 Block IIF/III satellites)Altitude: 20,000 kmLaunches: 2007-2011

SENSORSType: Broadband VHF receiversCapability: Event time, 3D location, TECLightning/sec/sat: ~ 1 - 10Coverage: 1 gnd stat. (regional, real-time) ~ 4 gnd stats. (global, real-time)

V-Sensor

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ELVES observed by ISUAL

8 ms1 ms

Samples of E-Field Changes

IC +CG

-CG Energetic -CG

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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.

Hilbert Transform

Match peaks among stations

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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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Radar EdotX

LASA vs. NEXRAD: able to outline structures of active storm cells. Can be used to now-cast

severe storms

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2-D location accuracy, < 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 efficiencyA 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 cellNotice the source height development. 498 pts in 50 min

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Great Plains Array deployed in April, 2005Algorithms 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)

Blue: PLK

Green: GNV

Red: TPA

Black: TLH

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

LB cutoff freq

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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.