Goddard Lidar Observatory for Winds GLOW Wind Profiling

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 GODDARD SPACE FLIGHT CENTER

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 355 nm 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, ROSES 07 -WLS (Dr. Ramesh Kakar) GODDARD SPACE FLIGHT CENTER

Overview for GLOW 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) GODDARD SPACE FLIGHT CENTER 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 GODDARD SPACE FLIGHT CENTER

Upgrades for GLOW • Laser ( 50 Hz, 25 m. J/pulse, Diode pumped ) • Reference Signal Measurement • Electronics ( Preamps, discriminators, boxcar integrators) • Etalon Calibration GODDARD SPACE FLIGHT CENTER

Laser • Diode Pumped, 50 Hz, 20 m. J/pulse • More Stable seed laser • Less energy consumption improves the temperature stability inside GLOW GODDARD SPACE FLIGHT CENTER

Reference Measurement Reference Signal Sampling Optics Laser M 1 BS R=95%, T=5% Lidar Signal+ Reference Signal Fiber Collimator To Receiver IF Lidar Signal Fiber Collimator From Telescope GODDARD SPACE FLIGHT CENTER Reference Signal Fiber

Etalon Calibration Scan GODDARD SPACE FLIGHT CENTER

Wind Measurements in 2009 • From Feb. 21 to Oct. 20, 50 days, 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 GODDARD SPACE FLIGHT CENTER

Measurement Errors GODDARD SPACE FLIGHT CENTER

Results from March 2009 Campaign GODDARD SPACE FLIGHT CENTER

Weather Conditions ref 0903201250. edg 0. 742 Cloud ref 0903240002. edg 2. 0986 Thin Cloud 8 -10 km ref 0903201918. edg 1. 2136 Clear ref 0903240249. edg 1. 7475 Clear ref 0903202057. edg 3. 35 Clear ref 0903242108. edg 2. 5064 Thin Cloud 8 and 11 km ref 0903210037. edg 0. 8791 Clear ref 0903250000. edg 3. 7403 Increasing at 8, 11 km ref 0903220247. edg 5. 1409 Clear ref 0903250410. edg 2. 7287 Increasing at 8, 11 km ref 0903222005. edg 0. 4775 Clear mcs 0903301411. edg 2. 234722 Clear ref 0903222105. edg 0. 3003 Clear mcs 0903301644. edg 0. 561111 Clear ref 0903222146. edg 2. 0066 Clear mcs 0903301721. edg 7. 336667 Clear ref 0903230005. edg 3. 4847 Clear mcs 0903310051. edg 1. 013611 Clear ref 0903230439. edg 2. 7164 Clear mcs 0903311302. edg 3. 508333 Thin Clouds at 10 ref 0903231856. edg 5. 0214 Thin Cloud 8 -10 km GODDARD SPACE FLIGHT CENTER

Results from March 2009 Campaign March 22 -23, 2009 GODDARD SPACE FLIGHT CENTER

Results from March 2009 Campaign March 30 -31, 2009 GODDARD SPACE FLIGHT CENTER

Comparison with Radio Sondes GODDARD SPACE FLIGHT CENTER

Comparison with IAD Sondes GODDARD SPACE FLIGHT CENTER

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 GODDARD SPACE FLIGHT CENTER

Comparison with Radio Sondes GODDARD SPACE FLIGHT CENTER

GLOW Lidar System Parameters Wavelength Telescope/Scanner Area Laser Linewidth (FWHH) Laser Energy/Pulse Etalon FSR Etalon FWHH Edge Channel Separation Locking Channel Separation Interference filter BW (FWHH) PMT Quantum Efficiency GODDARD SPACE FLIGHT CENTER 354. 7 nm 0. 116 m 2 80 MHz 25 m. J @ 50 pps 12 GHz 1. 7 GHz 5. 1 GHz 1. 7 GHz 150 pm 22%

2 Sampling strategy: 1 3 5 • LOS scans at multiple azimuths in repeating cycle (5 -10 LOS /cycle) 4 • 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 (30 s 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) GODDARD SPACE FLIGHT CENTER 2 1 5 4 3

Backups GODDARD SPACE FLIGHT CENTER

2 1 5 4 GODDARD SPACE FLIGHT CENTER 3

Combined Molecular Sensitivity vs. T and v T= 150 K to 350 K , GODDARD SPACE FLIGHT CENTER v = 0 to 100 m/s