Transcript NASA/GSFC Scanning Raman Lidar measurements of water vapor and clouds during IHOP (Whiteman)

NASA/GSFC Scanning Raman Lidar
measurements of water vapor and
clouds during IHOP
David N. Whiteman/NASA-GSFC, Belay Demoz/UMBC
Paolo Di Girolamo/Univ. of Basilicata, Igor Veselovskii, Joe Comer, Ruei-Fong
Lin/UMBC, Gerry McIntire/Raytheon
Acknowledgement: Interdisciplinary Research, Jim Dodge, NASA/HQ
Outline
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Scanning Raman Lidar (SRL)
– Extensive system modifications prior to IHOP
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Error characterization
– May 22 dryline event
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Measurement example
– June 3-4 bore
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June 19-20
– Bore case
– Cirrus cloud modeling study
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Telescopes: 0.76 and 0.25 m
Nd:YAG (9W @ 355 nm)
Windows
12 channel AD/PC
IHOP Accomplishments
– >200 hours
– Factor of 10 increase in water
vapor signal
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High quality daytime
measurements
– Aerosol depolarization
 Cirrus cloud studies
– RR Temperature (DiGirolamo et.
al.)
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Demonstration of eye-safe
concept
– Liquid water
 Cloud droplet retrieval studies
Scanning Raman Lidar
Water Vapor Mixing Ratio Precision
(Dryline May 22, 2002 - see Demoz et. al.)
• Full
Resolution (1 minute, 30 meters)
• Less than 10% to beyond 2 km.
• As Distributed (2 min, 60-210 meters)
• day <10% in BL
• night <2% in BL, <10% to 6km
Measurement
improvements
permit
convective
processes to be
studied
throughout the
diurnal cycle
Day
Night
Raman Airborne Spectroscopic Lidar (RASL)
Recent ground-based measurements validate the RASL system
modeling - Appl Opt., 40, No. 3, 375-390 (2001)
• water vapor, aerosol backscatter/extinction/depolarization,
cloud liquid water
• 10 km flight altitude
• 10 second nighttime, 2 minute daytime profiles
• <10% random error throughout profile, <5% in BL
Example
June 3-4
(See Koch et. al.)
The full dataset
The June 4 bore
Night
Day
Night
June 4, 2002 Bore
SRL mixing ratio, FMCW backscatter
June 4, 2002 Bore
SRL mixing ratio, FMCW backscatter
IHOP Analysis Update
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Preliminary release of all priority water vapor data
– Final release awaiting IHOP specific calibration
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Data distributed to 6 km
– Higher altitude data awaiting correction for temperature
dependence of water vapor spectrum
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Aerosol datasets require extra attention
– Correction for finite filter width and temperature
dependence of rotational Raman scattering
– Depolarization calibration
June 19-20, 2002
Thunderstorm outflow case
Anvil/Cirrus outflow
UT humidification
Falling ice?
Wave propagation?
Storm Motion
Density/Bore wave
June 19-20 Bore (See also Flamant et. al.)
Evidence
action in several locations
Day of wave
Night
Upper Troposphere Humidification and
Cirrus Cloud Evolution
Theta
Sequence of RH with
respect to ice up to 12 km
Cirrus evolution modeling case. Particle size and ice
water content coming…
Comparison of Measurements and Modeling
Model inputs: theta, RHi, P, Size Distribution for each grid box and W (uniform vertical
wind for the entire air column). Size and IWC estimates from lidar coming…
Conclusions and the Future
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Working hypothesis of waves on June 20
– Mechanical lift up to 6 km
– Waves in cirrus clouds induced by shear
 GLOW and SRL Scorer calculations
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Continue cirrus cloud modeling comparison
– Extend the time domain of the model
– Couple 2-D cloud and mesoscale models
– Seeding and source of wave energy for lower cirrus cloud layer
 Simulate wave motion and study effects on microphysics
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IHOP Data processing
– Final release of water vapor data
 IHOP specific water vapor calibration
– Aerosol and liquid water analysis
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SRL
– Automated and eye-safe
– Repackage in c-tainer
Oscillations in the lower cirrus layer
June 2-4 Clouds