Non-coherent Laser Radar Measurements Of Atmospheric Wind Speed

In this dissertation,a method of atmospheric wind velocity measurement using an incoherent lidar is presented systematically. The method is used to detect Doppler shift by the transmissivity of iodine absorption filter. The analysis shows the high measuring sensitivity and accuracy can be obtained using this method. The principle of measuring Mie-Scattering and Rayleigh-Scattering simultaneously in the troposphere(<12 Km) is analysed. The limitation which only using Mie-Scattering or Rayleigh-Scattering previously for detecting atmospheric wind velocity is broken. Owing to present the aerosol which varies along with different time, place and altitude in the troposphere and Rayleigh-Scattering spectrum varies along with atmosphere temperture, the result of measuring wind velocity should be corrected according to the aerosol content and atmospheric temperture. The calibrated curve and errors of wind velocity measurement are calculated under the circumstances of different Rb and temperture.A Fourier analysis method which is used to measure atmosphere temperature is proposed for the first time. The method uses least-squares fit for obtaining the atmospheric temperature through back-scattering spectrum of different height which is drived from convolution curves, considering the influence of the aerosol. The transmitter is a pulse injection harmonious Nd:YAG lader with double frequence, which makes vertical incidence and frequency scan. The sampling frequency interval is 125 MHz. By selecting I2 1109 absorption spectrum line to be edge filter, the transmission curve produced by atmospheric back-scattering spectrum through the iodine cell is examined by changes of transmission ratios. The measuring sensitivity and error of wind velocity are simulated from true system parameter and standard atmospheric model.The result of correlation experiments using the incoherent lidar system shows the wide scope of wind measurement and accuracy. The error of wind velocity under different circumstances is analysed. If a higher measuring sensitivity of the lidar system is desired, the multi-pulse average and background-noise reduction technology can improve SNR of measuring velocity and vertical range resolution. The photo-counting technology can increase measurement distance and sensitivity.