global lightning observations. optical transient detector ( launched april, 1995 ) optical transient...
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Global Lightning Observations
Global Lightning Observations
Optical Transient Detector( launched April, 1995 )
Optical Transient Detector( launched April, 1995 )
Lightning Imaging Sensor( launched November, 1997 )
Lightning Imaging Sensor( launched November, 1997 )
Lightning Detection from Low Earth OrbitLightning Detection from Low Earth Orbit
LIS on TRMMLIS on TRMM
Climatology: BasicsClimatology: Basics
•5 years of OTD, 6 years of LIS data
•Adjusted for detection efficiency J. Atmos. Oc.
Tech., 2002
• diurnally corrected
• ground-validated
• intercalibrated
•Scaled by satellite viewing
•Global flash rate: 45 fl / sec ± 10% J. Geophys. Res., 2003
•5 years of OTD, 6 years of LIS data
•Adjusted for detection efficiency J. Atmos. Oc.
Tech., 2002
• diurnally corrected
• ground-validated
• intercalibrated
•Scaled by satellite viewing
•Global flash rate: 45 fl / sec ± 10% J. Geophys. Res., 2003
High Resolution Full Climatology Annual Flash Rate
High Resolution Full Climatology Annual Flash Rate
Global distribution of lightning from a combined nine years of observations of the NASA OTD (4/95-3/00) and LIS (1/98-12/03) instruments
Global distribution of lightning from a combined nine years of observations of the NASA OTD (4/95-3/00) and LIS (1/98-12/03) instruments
9-year inter-calibrated time series
“Best possible” gridded data set for anomaly studies (internanual variability / ENSO)
9-year inter-calibrated time series
“Best possible” gridded data set for anomaly studies (internanual variability / ENSO)
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Climatology: GlobalClimatology: Global
(higher resolution)(higher resolution)
Climatology: Diurnal cycle
Climatology: Diurnal cycle
( Local hour )( Local hour )
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Climatology: Diurnal cycle
Climatology: Diurnal cycle
( UTC Hour )( UTC Hour )
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Global lightning is modulated on annual & diurnal time scales, as well as seasonally
and interannually
Climatology:
Distributions
Climatology:
Distributions
•NH summer dominates
•Expected semiannual signal in tropics
•NH summer dominates
•Expected semiannual signal in tropics
Lightning Responsive to Interannual
Variability
Lightning Responsive to Interannual
Variability
Winter 1997-98 (El Niño)
Winter 1998-99 (La Niña)
LIS Ocean OverpassLIS Ocean Overpass
LIS Land OverpassLIS Land Overpass
Flash Rate Coupled to Mass in the Mixed-phase Region
Flash Rate Coupled to Mass in the Mixed-phase Region
0 oC
Easterly Wave Regime Summary
Conceptual model for W. Africa and….
What did we do?
• Used a combination of TRMM PR, LIS and NCEP Reanalysis data to examine composited convective structure as a function of easterly wave phase over EPIC and W. African domains.
………For EPIC: Rotate convective types 30-45o clockwise
Scattered
Dissipating
Increasing coverage
NORTH
RIDGE
TROUGH
SOUTH
Intense/Vertically Developed
Widespread
What did we find?
• Systematic hierarchy of vertical development, rainfall, lightning, and area coverage (frequency) regimes as a function of wave phase.
Monsoon: Less vertically developed
TRMM- LIS FLASH RATE
TRMM PR 7-10 km
AREA-MEAN ICE WATER CONTENT
African E. Waves: June-October 1998-2000
Diurnal Cycles of Area-Mean Lightning and 7-10 km Precip. Ice Water
W. Africa Tropical E. Wave: Regime Area Mean 7-10 km IWCs vs. LIS Flash Rate
Northerly Trough
Southerly Ridge
All Phases • Slopes and zero-flash intercepts in each regime similar
• Linear R2 good or better than non-linear
• Consistent with previous bulk scaling
arguments
• Scatter plots of area-mean diurnal cycle FR and 7-10 km IWC over the diurnal cycle for phases (N, T, R, S)
• 4-Pt. running mean applied to diurnal cycles to account for TRMM sampling
• Convective spectrum (radar-based)
• Lightning production
• Convective spectrum (radar-based)
• Lightning production
Deep convective frequency and lightning
production
Deep convective frequency and lightning
productionWarm / non-mixed-phaseMid / deep convectiveMid / deep stratiform
Warm / non-mixed-phaseMid / deep convectiveMid / deep stratiform
Climatology : IC / CG ratio
Climatology : IC / CG ratio
Lightning Connection to Thunderstorm Updraft,
Storm Growth and Decay
Lightning Connection to Thunderstorm Updraft,
Storm Growth and Decay
• Total Lightning —responds to updraft velocity and concentration, phase, type of hydrometeors — integrated flux of particles• WX Radar — responds to concentration, size, phase, and type of hydrometeors- integrated over small volumes• Microwave Radiometer — responds to concentration, size, phase, and type of hydrometeors — integrated over depth of storm (85 GHz ice scattering)• VIS / IR — cloud top height/temperature, texture, optical depth
• Total Lightning —responds to updraft velocity and concentration, phase, type of hydrometeors — integrated flux of particles• WX Radar — responds to concentration, size, phase, and type of hydrometeors- integrated over small volumes• Microwave Radiometer — responds to concentration, size, phase, and type of hydrometeors — integrated over depth of storm (85 GHz ice scattering)• VIS / IR — cloud top height/temperature, texture, optical depth
OTD Overpass
of Tornadic Storms in Oklahoma
, 1995
OTD Overpass
of Tornadic Storms in Oklahoma
, 1995
OTD Total Lightning vs. NLDN CGs
OTD Total Lightning vs. NLDN CGs
• Six supercells at time of LIS overpass dominated by in-cloud (IC)
lightning: >96% of all lightning
• IC:CG ratio ranges from 20-28:1
• One of the more extreme storm total flash rates worldwide during TRMM
• 40 people died in Oklahoma due to the twisters and 675 were injured.
• Total damage of $1.2 billion.
• Five deaths, 100 injuries and heavy damage also incurred in the Wichita,
Kansas metro area.
The Central Oklahoma Tornado
Outbreak of May 3, 1999 The Central Oklahoma Tornado
Outbreak of May 3, 1999
TRMM/LIS Overpass During May 3, 1999 Tornado Outbreak
- Overpass between 04:03 and 04:04 UTC -- Tornado on ground between 03:50 and 03:57 UTC -
F3Stroud
Tulsa
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sLIS Lightning Observations
LIS Total Lightning Identifies Cellular Storm Structure
LIS Total Lightning Identifies Cellular Storm Structure
F3Stroud
Tulsa
LIS Lightning Observations
LIS and TMI 85 GHz Microwave
match: lightning tracks cloud ice LIS and TMI 85 GHz Microwave
match: lightning tracks cloud ice TMI Microwave
CGTotal
Oklahoma Storms Dominated by In-cloud Lightning
Oklahoma Storms Dominated by In-cloud Lightning
LIS and NEXRADLIS and NEXRAD
LIS Lightning ObservationsLIS Lightning Observations NEXRAD ReflectivityNEXRAD Reflectivity
NEXRAD Reflectivity NEXRAD Velocity
NEXRAD observes rotation in the LIS-identified cells
NEXRAD observes rotation in the LIS-identified cells
Why observe lightning?(Forecasting)
Why observe lightning?(Forecasting)
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TimeTime
Tornadotime
TornadotimeLightningLightning
RadarRadar
Pre-tornado Lightning Signature
Pre-tornado Lightning Signature
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Major Points for Severe Weather
Major Points for Severe Weather
• Primary lightning signature is high flash rates and the “jump”
• Lightning flash rate is correlated storm intensity - higher rate implies stronger storm.
Evolution of the lightning activity follows the updraft. Increasing activity
means the storm intensifying; decreasing activity means the updraft is
weakening.
A jump in lightning activity is associated with a pulse in updraft intensity
• These signatures, in conjunction with other NWS assets can be used to:
Separate intensifying from weakening storms Identify storms in process of going severe
Quickly determine the most intense storms in a complex system
Improved warning times
Reduced false alarms rates
• Primary lightning signature is high flash rates and the “jump”
• Lightning flash rate is correlated storm intensity - higher rate implies stronger storm.
Evolution of the lightning activity follows the updraft. Increasing activity
means the storm intensifying; decreasing activity means the updraft is
weakening.
A jump in lightning activity is associated with a pulse in updraft intensity
• These signatures, in conjunction with other NWS assets can be used to:
Separate intensifying from weakening storms Identify storms in process of going severe
Quickly determine the most intense storms in a complex system
Improved warning times
Reduced false alarms rates
Observe Storm
Evolution
Geostationary Vantage
Point
Lightning Sensing from GEO
Lightning Sensing from GEO
•Climate Monitoring
•Storm Development
• Ice-phase precipitation estimates
•Severe Weather Now-casting
•Data assimilation and model inputs
•Atmospheric chemistry
•Climate Monitoring
•Storm Development
• Ice-phase precipitation estimates
•Severe Weather Now-casting
•Data assimilation and model inputs
•Atmospheric chemistry
Getting to GEOGetting to GEO
•Long-term goal is geostationary orbit
•Engineering straightforward
•~ 6 km pixel size possible at nadir
•Go beyond LEO “snapshots” and capture storm evolution
•Significant forecast potential (data assimilation, severe weather nowcasting)
•Long-term goal is geostationary orbit
•Engineering straightforward
•~ 6 km pixel size possible at nadir
•Go beyond LEO “snapshots” and capture storm evolution
•Significant forecast potential (data assimilation, severe weather nowcasting)
LMS Instrument CharacteristicsLMS Instrument Characteristics
• Extension of the LIS/OTD technology
• 8 km spatial resolution (same as the OTD)
• 40 kg
• 150 watts running all RTEPs; can be dropped significantly
• 200 kbits per sec. data rate (continuous )
• products available in near real time (20 sec.)
• Status
• technique has been successfully demonstrated
• performance goals readily realizable
• all technology issues have been resolved
• all major subsystems nearing completion (brass-board level)
• Extension of the LIS/OTD technology
• 8 km spatial resolution (same as the OTD)
• 40 kg
• 150 watts running all RTEPs; can be dropped significantly
• 200 kbits per sec. data rate (continuous )
• products available in near real time (20 sec.)
• Status
• technique has been successfully demonstrated
• performance goals readily realizable
• all technology issues have been resolved
• all major subsystems nearing completion (brass-board level)
GEOGEO
Hail/GraupelHail/Graupel
RainRain
Snow/IceSnow/Ice
++
++
+ = Positive Charge + = Positive Charge = Negative Charge = Negative Charge
Thunderstorm StructureThunderstorm Structure
Lightning Connection to Thunderstorm Updraft,
Storm Growth and Decay
Lightning Connection to Thunderstorm Updraft,
Storm Growth and Decay
• Total Lightning —responds to updraft velocity and concentration, phase, type of hydrometeors — integrated flux of particles• WX Radar — responds to concentration, size, phase, and type of hydrometeors- integrated over small volumes• Microwave Radiometer — responds to concentration, size, phase, and type of hydrometeors — integrated over depth of storm (85 GHz ice scattering)• VIS / IR — cloud top height/temperature, texture, optical depth
• Total Lightning —responds to updraft velocity and concentration, phase, type of hydrometeors — integrated flux of particles• WX Radar — responds to concentration, size, phase, and type of hydrometeors- integrated over small volumes• Microwave Radiometer — responds to concentration, size, phase, and type of hydrometeors — integrated over depth of storm (85 GHz ice scattering)• VIS / IR — cloud top height/temperature, texture, optical depth
Climatology:
Distributions
Climatology:
Distributions
•Deep tropics ~ 2x subtropics
•Three tropical “chimneys” dominate (Carnegie curve)
•Americas dominate annual cycle
•Deep tropics ~ 2x subtropics
•Three tropical “chimneys” dominate (Carnegie curve)
•Americas dominate annual cycle
GEO -EastGEO -East
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