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 Wintergreen, VA June, 2009

G O D D A R D S P A C E F L I G H T C E N T E R NASA Wind Lidar Science (WLS) Experiment at Howard Beltsville Research Facility GOALS Develop understanding of direct detection (GLOW) and coherent Doppler lidar (VALIDAR) wind performance for various cloud and aerosol loading conditions (pollution, cirrus) 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). Hands-on student training Funded by NASA SED, ROSES07-WLS (Dr. Ramesh Kakar)

G O D D A R D S P A C E F L I G H T C E N T E R Measurement summary Vertical resolution=250 m  t=3 min Altitude range= 2 to 5 km Elevation angle= 45 deg Scan pattern = 4 directions: (N,S,E,W)+vertical Dwell per LOS = 30 sec GLOW -February 24, 2009 RS92 Sonde 1RS92 Sonde 2 RS92 Sonde 1RS92 Sonde 2 m/s deg Goddard Lidar Observatory for Winds (GLOW) mobile Doppler lidar Direct detection Doppler Lidar system Measures clear air wind profiles using molecular backscatter Serves as technology testbed for air and space based lidar technologies Multiple field campaigns since MHz wind profiler and local radiosonde launches provide correlative measurements for the wind lidar systems Direct Detection Doppler lidar profiling at Howard Beltsville Research Facility GLOW mobile Doppler lidar

G O D D A R D S P A C E F L I G H T C E N T E R 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 45 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)

G O D D A R D S P A C E F L I G H T C E N T E R Wavelength354.7 nm Telescope/Scanner Area0.116 m 2 Laser Linewidth (FWHH)80 MHz Laser Energy/Pulse 25 50pps Etalon FSR 12 GHz Etalon FWHH1.7 GHz Edge Channel Separation5.1 GHz Locking Channel Separation 1.7 GHz Interference filter BW (FWHH)150 pm PMT Quantum Efficiency22% GLOW Lidar System Parameters

G O D D A R D S P A C E F L I G H T C E N T E R GLOW Signal Dynamic Range

G O D D A R D S P A C E F L I G H T C E N T E R February 24, 2009  z=250 m ;  t=3 min Clouds RS92 sonde 2 km ~45 min Signals exceed max count rate below 2 km. PMTs gated off

G O D D A R D S P A C E F L I G H T C E N T E R February 24, 2009 GLOW profile: 0126 UT Sonde launched: 0059 UT GLOW 3 min average; Sonde averaged to  z=250 m

G O D D A R D S P A C E F L I G H T C E N T E R Exploring Differences in Spatial and Temporal Sampling- GLOW vs Sonde = sonde altitude at time of lidar measurement. Assumes rise rate of 5 m/s.

G O D D A R D S P A C E F L I G H T C E N T E R February 24, 2009 GLOW profile: 0150 UT Sonde launched: 0128 UT GLOW 30 min running average; Sonde averaged to  z=250 m

G O D D A R D S P A C E F L I G H T C E N T E R February 24, 2009

G O D D A R D S P A C E F L I G H T C E N T E R February 24, 2009 GLOW profile: 0417 UT Sonde launched: 0329 UT GLOW 33 min running average; Sonde averaged to  z=250 m

G O D D A R D S P A C E F L I G H T C E N T E R GLOW-Sonde February 24, 2009 GLOW profile: 0357 UT Sonde launched: 0329 UT GLOW 33 min running average; Sonde averaged to  z=250 m

G O D D A R D S P A C E F L I G H T C E N T E R March 18, 2009  z=250 m ;  t=3 min

G O D D A R D S P A C E F L I G H T C E N T E R April 9, 2009  z=250 m ;  t=3 min

G O D D A R D S P A C E F L I G H T C E N T E R March 11, 2009  z=250 m ;  t=3 min ; 9 min running average

G O D D A R D S P A C E F L I G H T C E N T E R March 11, 2009  z=100 m ;  t=3 min; 3 min average

G O D D A R D S P A C E F L I G H T C E N T E R Objectives l Demonstrate atmospheric wind measurement capabilities l Prove new concepts and test components l Validate space simulation instrument model Edge Technique Lidar System (1995) Edge Technique Lab Testbed Transmitter Wavelength (nm) :1064 Repetition rate (Hz) :10 Energy per pulse (J) :0.12 Laser bandwidth (MHz) :40 Receiver Telescope diameter (m) :0.406 Interference filter bandwidth (nm) :5 Quantum efficiency :0.40(analog) 0.04(PC) Fabry-Perot interferometer Spectral width FWHM (MHz) :100 Free Spectral Range (GHz) :3 10 sec (100 shot) averaging/LOS; 22 m vertical resolution 1. Korb, C. L, B. Gentry, and S. X. Li, (1997) “Edge Technique Doppler Lidar Wind Measurements with High Vertical Resolution,” Applied Optics, 36, pp PBL Lidar Winds 1

G O D D A R D S P A C E F L I G H T C E N T E R Future Work Continue wind profile data collection. – 2 to 3 days a week – Coordinate with NWAVES Examine representativeness of data sampling and averaging schemes Continue inter-comparisons with other wind sensors (VALIDAR, ACARS, sondes, profiler Examine effects of clouds and aerosols on the molecular wind measurement using Raman lidar backscatter products as a reference Resurrect the double edge aerosol receiver for PBL studies

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

G O D D A R D S P A C E F L I G H T C E N T E R Direct Detection Doppler lidar profiling at Howard Beltsville Research Facility Measurement summary Vertical resolution=250 m  t=3 min Altitude range= 2 to 5 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)

G O D D A R D S P A C E F L I G H T C E N T E R February 24, 2009 GLOW profile: 0417 UT Sonde launched: 0329 UT GLOW 33 min running average; Sonde averaged to  z=250 m

G O D D A R D S P A C E F L I G H T C E N T E R GLOW-Sonde February 24, 2009 GLOW profile: 0417 UT Sonde launched: 0329 UT GLOW 33 min running average; Sonde averaged to  z=250 m

G O D D A R D S P A C E F L I G H T C E N T E R February 24, 2009 GLOW profile: 0126 UT Sonde launched: 0059 UT GLOW 33 min running average; Sonde averaged to  z=250 m

G O D D A R D S P A C E F L I G H T C E N T E R March 11, min

G O D D A R D S P A C E F L I G H T C E N T E R March 11, min

G O D D A R D S P A C E F L I G H T C E N T E R March 11, min 100 m

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

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

G O D D A R D S P A C E F L I G H T C E N T E R March 31, 2009 GLOW profile: 0150 UT Sonde launched: 0128 UT Sonde averaged to  z=250 m

G O D D A R D S P A C E F L I G H T C E N T E R March 23, 2009  z=250 m ;  t=3 min

G O D D A R D S P A C E F L I G H T C E N T E R February 24, 2009

G O D D A R D S P A C E F L I G H T C E N T E R February 24, 2009

G O D D A R D S P A C E F L I G H T C E N T E R March 30, 2009  z=250 m ;  t=3 min

G O D D A R D S P A C E F L I G H T C E N T E R March 31, 2009 GLOW profile: 0140 UT Sonde launched: 0128 UT GLOW 30 min running average; Sonde averaged to  z=250 m