NASA/GSFC Scanning Raman Lidar measurements of water vapor and clouds during IHOP (Whiteman)
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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
Scanning Raman Lidar (SRL)
– Extensive system modifications prior to IHOP
Error characterization
– May 22 dryline event
Measurement example
– June 3-4 bore
June 19-20
– Bore case
– Cirrus cloud modeling study
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
High quality daytime
measurements
– Aerosol depolarization
Cirrus cloud studies
– RR Temperature (DiGirolamo et.
al.)
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
Preliminary release of all priority water vapor data
– Final release awaiting IHOP specific calibration
Data distributed to 6 km
– Higher altitude data awaiting correction for temperature
dependence of water vapor spectrum
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
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
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
IHOP Data processing
– Final release of water vapor data
IHOP specific water vapor calibration
– Aerosol and liquid water analysis
SRL
– Automated and eye-safe
– Repackage in c-tainer
Oscillations in the lower cirrus layer
June 2-4 Clouds