VISIBLE WAVELENGTH DOPPLER LIDAR FOR MEASUREMENT OF WIND AND AEROSOL PROFILES DURING DAY AND NIGHT

An incoherent (direct detection) Doppler lidar is developed that opera tes in the middle of the visible spectrum and measures wind and aeroso l profiles during the day and night from the planetary boundary layer to the lower stratosphere. The primary challenge of making a lidar mea surement in the visible spectrum during daylight hours is the strong p resence of background light from the sun. To make a measurement of thi s type, the laser line must be isolated spectrally to the greatest ext ent possible. This has been accomplished through the use of a multiple etalon Fabry-Perot interferometer in combination with a narrow-band f ilter. The incoherent technique and system are a modified version of t he Fabry-Perot interferometer and image-plane detector technology deve loped for an earlier Doppler lidar developed at the University of Mich igan and for the High-Resolution Doppler Imager (HRDI) now flying on t he Upper Atmosphere Research Satellite. The incoherent Doppler analysi s is discussed and sample measurements are shown. Winds are measured i n the boundary layer with 100-m vertical resolution and 5-min temporal resolution with 1 to 3 m s(-1) accuracy.