airborne measurement of horizontal wind and moisture transport using co-deployed doppler and dial...
TRANSCRIPT
Airborne Measurement of Horizontal Wind and Moisture Transport Using
Co-deployed Doppler and DIAL lidars
Mike Hardesty, Alan Brewer, Brandi McCarty, Christoph Senff, and Ed
TollerudNOAA/ETL and University of
Colorado/CIRES
Gerhard Ehret, Andreas Fix, Goraszd Poberaj, Martin Wirth, and
Christoph Kiemle DLR/Lidar Group
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Measurement Technique (horizontal winds)
• Installed a wedge scanner to direct the lidar beam 20 degrees off-nadir
• Fixed the beam azimuth direction at 90 degrees relative to the aircraft
• Adjusted azimuth to compensate for aircraft yaw using real time ground hits
• Measure winds, water vapor and aerosol with 150 m vertical and horizontal resolution (processed to 1.5 km resolution)
• Subtract residual ground velocity from each measured atmospheric velocity
• Fly box patterns to measure moisture convergence
• Comparisons: Dropsondes
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Horizontal Winds: 9 June
Forecast showed low level jet
Flight track to measure jet
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Lidar/Dropsonde Comparisons
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Northern leg wind and water vapor
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Lidar and dropsonde flux comparison
DIAL/Doppler lidar
Dropsonde
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Dropsonde/Lidar comparison near jet max
• Dropsonde/lidar flux comparisons show good agreement for north-south component
• Non-negligible east-west component at higher altitudes (lidar will underestimate)
• Could be improved by noting the orientation of the jet axis and correcting velocity measurements
• Lidar measurements have higher resolution, see smaller scales
• Analyzing data to see if this is important
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Dropsonde-Scale Moisture Transport
South (blue) and North (black) transportDropsonde transport
measurements
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Vertical Wind Measurements
• Direct the lidar beam vertically through a nadir port in the Falcon
• Use the real-time estimate of the surface velocity to determine vertical pointing
• Adjust turning mirror to compensate for Falcon pitch angle
• Measure winds, water vapor and aerosol with 150 m vertical and horizontal resolution
• Subtract residual ground velocity from each atmospheric velocity
• Repeat aircraft tracks over multiple missions
• Comparisons: King-Air and surface flux measurements
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Vertical velocities
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Vertical Velocity Variance
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Lidar/King Air Comparison June 7
Lidar
King Air
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Repeat over same track
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17:40 17:41 17:42 17:43 17:44 17:45DLR DIAL water vapour mixing ratio
-101.90 -101.80 -101.70 -101.60 -101.50 -101.40 -101.30longitude
1.0
1.5
2.0
2.5
3.0
height (km)
1.0
1.5
2.0
2.5
3.0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 g/kg
UTC
17:40 17:41 17:42 17:43 17:44 17:45NOAA HRDL vertical wind velocity
0 10 20 30 40 50distance (km)
1.0
1.5
2.0
2.5
3.0
height (km)
1.0
1.5
2.0
2.5
3.0
-3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 m/s
UTC
NOAA-HRDL
x = 150 my = 150 m
DLR-DIAL
x = 200 m
y = 150 m
Combined Wind and Water Vapour Measurements
Spatial Averaging:
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-0.05 0.00 0.05 0.10 0.15 0.20 0.25 0.30g/kg*m/s
1500
2000
2500
3000
3500
altitude asl in m
0 200 400 600W/m2
Preliminary Flux Profile
First Measurement of Latent Heat Flux Profile by co-located airborne water vapor DIAL and
Doppler wind lidars
1
10
100
1000
10000
S(f)
0.0001 0.0010 0.0100
wavenumber [1/m]
10000 1000
wavelength [m] 2600m asl
H2O-DIALPower Spectrum
Flux Profile from Eddy-Correlation
(NOAA, DLR)
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Future : HRDL Upgrades
• HRDL is being repackaged for better aircraft performance• Modular design, fiber coupling• New processor under development for higher prf (1 kHz)• Deployment on NOAA ship this summer for New England
air quality experiment• Future plans: co-deployment with ozone lidar during
2005/2006 air quality studies
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Summary
• Demonstrated the capability to make high precision measurements of boundary layer horizontal and vertical velocities using co-deployed DIAL and Doppler lidars
• Computed vertical fluxes using eddy correlation• Computed horizontal wind component and single
component moisture transport• Compared turbulence measurements using King Air in
situ measurements• Compared lidar and dropsonde transport measurements• Underway: examine backscatter weighting of vertical
velocity measurements (effect on a spacebased wind system)
• Gratefully acknowledge support of USWRP and NPOESS/IPO for this research