global lightning observations. optical transient detector ( launched april, 1995 ) optical transient...

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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