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

OutlineOutline

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

Scanning Raman LidarScanning Raman Lidar 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

Water Vapor Mixing Ratio PrecisionWater Vapor Mixing Ratio Precision

(Dryline May 22, 2002 - see Demoz et. al.)(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

NightDay

Raman Airborne Spectroscopic Lidar (RASL)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

ExampleExampleJune 3-4 June 3-4

(See Koch et. al.)(See Koch et. al.)

The full dataset

DayNight Night

The June 4 bore

June 4, 2002 BoreJune 4, 2002 BoreSRL mixing ratio, FMCW backscatterSRL mixing ratio, FMCW backscatter

June 4, 2002 BoreJune 4, 2002 BoreSRL mixing ratio, FMCW backscatterSRL mixing ratio, FMCW backscatter

IHOP Analysis UpdateIHOP 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, 2002June 19-20, 2002Thunderstorm outflow caseThunderstorm outflow case

Storm Motion

Anvil/Cirrus outflow

Density/Bore wave

Falling ice?

Wave propagation?

UT humidification

June 19-20 Bore June 19-20 Bore (See also Flamant et. al.)(See also Flamant et. al.)

Evidence of wave action in several locationsDay Night

Upper Troposphere Humidification and Upper Troposphere Humidification and Cirrus Cloud EvolutionCirrus 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 ModelingComparison 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 FutureConclusions 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 layerOscillations in the lower cirrus layer

June 2-4 CloudsJune 2-4 Clouds