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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, FL February , 2010.

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Huailin chen bruce gentry tulu bacha belay demoz demetrius venable destin fl february 2010

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, FL

February , 2010


Nasa wind lidar science wls experiment at howard beltsville research facility
NASA Wind Lidar Science (WLS) Experiment at Howard Beltsville Research Facility

GOALS

  • 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
Overview for GLOW Beltsville Research Facility

  • 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)

  • 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


Glow at beltsville research site
GLOW at Beltsville Research Site Beltsville Research Facility


Upgrades for glow
Upgrades for GLOW Beltsville Research Facility

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

  • Reference Signal Measurement

  • Electronics ( Preamps, discriminators, boxcar integrators)

  • Etalon Calibration


Laser
Laser Beltsville Research Facility

  • Diode Pumped, 50Hz, 20mJ/pulse

  • More Stable seed laser

  • Less energy consumption improves the temperature stability inside GLOW


Reference measurement

Laser Beltsville Research Facility

Reference Signal Sampling Optics

M1

BS R=95%, T=5%

Lidar Signal+ Reference Signal

Fiber

Collimator

Fiber

Collimator

Reference Signal Fiber

To Receiver

IF

Lidar Signal Fiber

Fiber

Collimator

From Telescope

Reference Measurement


Etalon calibration scan
Etalon Calibration Scan Beltsville Research Facility


Wind measurements in 2009
Wind Measurements in 2009 Beltsville Research Facility

  • 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
Measurement Errors Beltsville Research Facility


Results from march 2009 campaign
Results from March 2009 Campaign Beltsville Research Facility


Weather conditions
Weather Conditions Beltsville Research Facility


Results from march 2009 campaign1
Results from March 2009 Campaign Beltsville Research Facility

March 22-23, 2009


Results from march 2009 campaign2
Results from March 2009 Campaign Beltsville Research Facility

March 30-31, 2009


Comparison with radio sondes
Comparison with Radio Sondes Beltsville Research Facility


Comparison with radio sondes1
Comparison with Radio Sondes Beltsville Research Facility


Comparison with radio sondes2
Comparison with Radio Sondes Beltsville Research Facility


Comparison with radio sondes3
Comparison with Radio Sondes Beltsville Research Facility


Comparison with radio sondes4
Comparison with Radio Sondes Beltsville Research Facility


Comparison with radio sondes5
Comparison with Radio Sondes Beltsville Research Facility


Comparison with iad sondes
Comparison with IAD Sondes Beltsville Research Facility


Summary and future work
Summary and Future Work Beltsville Research Facility

  • 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


Comparison with radio sondes6
Comparison with Radio Sondes Beltsville Research Facility


GLOW Lidar System Parameters Beltsville Research Facility

Wavelength 354.7 nm

Telescope/Scanner Area 0.116 m2

Laser Linewidth (FWHH) 80 MHz

Laser Energy/Pulse 25 mJ @ 50pps

Etalon FSR 12 GHz

Etalon FWHH 1.7 GHz

Edge Channel Separation 5.1 GHz

Locking Channel Separation 1.7 GHz

Interference filter BW (FWHH) 150 pm

PMT Quantum Efficiency 22%


2 Beltsville Research Facility

1

3

5

4

2

1

5

3

4

  • 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)


Backups
Backups Beltsville Research Facility


2 Beltsville Research Facility

1

5

3

4


Combined Molecular Sensitivity vs. T and v Beltsville Research Facility

T= 150K to 350K , v = 0 to 100 m/s


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