Huailin Chen, Bruce Gentry, Tulu Bacha, Belay Demoz, Demetrius Venable Destin, FL

G O D D A R D S P A C E F L I G H T C E N T E R

Goddard Lidar Observatory for Winds (GLOW) Wind Profiling

from the Howard University Beltsville

Research Facility Huailin Chen, Bruce Gentry, Tulu Bacha, Belay Demoz, Demetrius

Venable

Destin, FLFebruary , 2010


NASA Wind Lidar Science (WLS) Experiment at Howard Beltsville

Research FacilityGOALS

• Develop understanding of direct detection (GLOW) wind speed and direction performance for various cloud and aerosol loading conditions (pollution, cirrus), using the 355nm backscatter ratios and water vapor data independently measured by the Raman lidar as well as synergistic measurements from the Beltsville instrument suite.

• Develop a seasonal data base archive for wind measurements.

• Intercomparison of coherent and direct detection Doppler lidars

• Compare Doppler lidar wind data to other sensors (Profiler, Radiosonde, ACARS).

Funded by NASA SED, ROSES07-WLS (Dr. Ramesh Kakar)


Overview for GLOW

Measurement summary •Vertical resolution=250 m t=3 min •Altitude range= 2 to 15 km•Elevation angle= 45 deg•Scan pattern = 4 directions: (N,S,E,W)+vertical•Dwell per LOS = 30 sec

Goddard Lidar Observatory for Winds (GLOW) mobile Doppler lidar

• Direct detection Doppler Lidar system• Measures clear air wind profiles using molecular backscatter• Serves as testbed for air and space based lidar technologies• Multiple field campaigns since 2000

Line of sight wind profiles are sequentially measured at 4 azimuth angles (N,S,E,W)+vertical. The multiple direction LOS profiles are combined to produce vertical profiles of horizontal wind speed and direction (right)


GLOW at Beltsville Research Site


Upgrades for GLOW

• Laser ( 50Hz, 25mJ/pulse, Diode pumped )

• Reference Signal Measurement

• Electronics ( Preamps, discriminators, boxcar integrators)

• Etalon Calibration


Laser

• Diode Pumped, 50Hz, 20mJ/pulse• More Stable seed laser• Less energy consumption improves the

temperature stability inside GLOW


Reference Measurement

Laser Reference Signal Sampling Optics

FiberCollimator

FiberCollimator

Reference Signal Fiber

From Telescope

Lidar Signal Fiber

M1

BS R=95%, T=5%

To Receiver

Lidar Signal+ Reference Signal

FiberCollimator

IF


Etalon Calibration Scan

-0.2

0

0.2

0.4

0.6

0.8

1

-8 -6 -4 -2 0 2 4 6

Etalon0903301344

aLockaEdge1aEdge2

Ener

gy N

orm

aliz

ed E

talo

n Li

nesh

ape

Func

tion

Frequency (GHz)


Wind Measurements in 2009

• From Feb. 21 to Oct. 20, 50days, 310 hours

• Variety weather conditions: different aerosol loadings, cirrus clouds at different altitude, front passage.

• GLOW-Validar Intercomparison: Feb 21-Mar 10. GLOW/Validar/AT/ALVICE HURL/Sonde/915 MHz profiler

• Mar. 2009 Campaign: Mar. 20-31 . GLOW/AT/ALVICE HURL/Sonde/915 MHz profiler

• Regular GLOW/Sonde comparisons


Measurement Errors

0

3000

6000

9000

1.2 104

1.5 104

0 2 4 6 8 10

GLOW_HBRF_11x1_250m_20091005T110050LT

Alt(

m)

9min and 33min Wind Speed Error (m/s)

0

3000

6000

9000

1.2 104

1.5 104

0 2 4 6 8 10

GLOW_HBRF_11x1_250m_20091005T110050LT

Alt(

m)

9min and 33min Wind Dir Error (deg)


Results from March 2009 Campaign


Weather Conditionsref0903201250.e

dg 0.742 Cloud ref0903240002.edg 2.0986 Thin Cloud 8-10km

ref0903201918.edg 1.2136 Clear ref0903240249.e

dg 1.7475 Clear


dg 2.5064 Thin Cloud 8 and 11km


dg 3.7403 Increasing at 8,11km


dg 2.7287 Increasing at 8,11km

ref0903222005.edg 0.4775 Clear mcs0903301411.

edg2.23472

2 Clear

ref0903222105.edg 0.3003 Clear mcs0903301644.

edg0.56111

1 Clear

ref0903222146.edg 2.0066 Clear mcs0903301721.

edg7.33666

7 Clear

ref0903230005.edg 3.4847 Clear mcs0903310051.

edg1.01361

1 Clear

ref0903230439.edg 2.7164 Clear mcs0903311302.

edg3.50833

3 Thin Clouds at 10

ref0903231856.edg 5.0214 Thin Cloud 8-

10km



00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00 03:00 06:00 09:000

5

10

15

Local Time (ET)

Alti

tude

MS

L (k

m)

Wind speed (m/s)

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10

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00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00 03:00 06:00 09:000

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10

15

Local Time (ET)

Alti

tude

MS

L (k

m)

Wind direction (degrees)

200

220

240

260

280

300

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340

360

March 22-23, 2009



12:00 15:00 18:00 21:00 00:00 03:00 06:00 09:00 12:00 15:00 18:000

5

10

15

Local Time (ET)

Alti

tude

MS

L (k

m)

Wind speed (m/s)

0

10

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30

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12:00 15:00 18:00 21:00 00:00 03:00 06:00 09:00 12:00 15:00 18:000

5

10

15

Local Time (ET)

Alti

tude

MS

L (k

m)

Wind direction (degrees)

200

220

240

260

280

300

320

340

360

March 30-31, 2009


Comparison with Radio Sondes

0

3000

6000

9000

1.2 104

1.5 104

-10 0 10 20 30 40 50 60 70

0 50 100 150 200 250 300 350 400

Mar 21 GLOW034301Sonde0330Sonde(m)GLOW(m)Sonde(m)GLOW(m)

Alti

tude

(m)

WindSpd(m/s)

Wind Dir (deg)



0

3000

6000

9000

1.2 104

1.5 104

-10 0 10 20 30 40 50 60 70

0 50 100 150 200 250 300 350 400


Alti

tude

(m)

WindSpd(m/s)

Wind Dir (deg)



0

3000

6000

9000

1.2 104

1.5 104

-10 0 10 20 30 40 50 60 70

0 50 100 150 200 250 300 350 400


Alti

tude

(m)

WindSpd(m/s)

Wind Dir (deg)

Thin Cloud



0

3000

6000

9000

1.2 104

1.5 104

-10 0 10 20 30 40 50 60 70

0 50 100 150 200 250 300 350 400


Alti

tude

(m)

WindSpd(m/s)

Wind Dir (deg)


Comparison with IAD Sondes

0

2000

4000

6000

8000

1 104

1.2 104

1.4 104

0 10 20 30 40 50 60

Mar 31 GLOW001315 and 005643 Sonde00Z

IADGLOWAlt(m)

IAD

WindSpd(m/s)


Summary and Future Work

•Wind measurement on regular basis•Sonde comparison validation

• Continue wind data collection. – 2 to 3 days a week – Coordinate with NWAVES

•Use the GLOW data in WRF model

• Participate field campaigns


Wavelength 354.7 nmTelescope/Scanner Area 0.116 m2

Laser Linewidth (FWHH) 80 MHzLaser Energy/Pulse 25 mJ @ 50ppsEtalon FSR 12 GHzEtalon FWHH 1.7 GHzEdge Channel Separation 5.1 GHzLocking Channel Separation 1.7 GHzInterference filter BW (FWHH) 150 pmPMT Quantum Efficiency 22%

GLOW Lidar System Parameters


Sampling strategy:• LOS scans at multiple azimuths in repeating cycle (5-10 LOS /cycle)

• Step stare scan pattern at fixed elevation angle (Typ. 45 deg) : 4 cardinal directions (N,S,E,W) + vertical

• Signals are range gated in 30 m bins, integrated and stored every 10 s. Three dwells (30s total) per LOS. Total time to complete scan: ~3 min

Post processing: • data averaged in range (default 250 m)• data can be accumulated in time by LOS (multiples of base 3 min)• corrections for atmos. T and P (RBS)

1

2

3

4

5

1

2

34

5


Backups


cos*1*

)()(v

cos*1*

)()(v

vv v

bygiven is vspeed windthe

,,,;21

ratios theand y sensitivit aGiven degrees. ofelevation at EW,S,N, azimuths 4 from

obtained are from Edg2 and Edg1 signals Measured

y

x

2y

2x

SensRRRR

SensRRRR

where

WESNiEdgEdgR

Sens

SN

SN

EW

EW

i

ii 1

2

3

4

5


Combined Molecular Sensitivity vs. T and vT= 150K to 350K , v = 0 to 100 m/s

Huailin Chen, Bruce Gentry, Tulu Bacha, Belay Demoz, Demetrius Venable Destin, FL

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Transcript of Huailin Chen, Bruce Gentry, Tulu Bacha, Belay Demoz, Demetrius Venable Destin, FL