Quad-Fabry-Perot etalon based Rayleigh Doppler lidar for 0.2-60km altitude wind, temperature and aerosol accurate measurement

Abstract Rayleigh Doppler lidar based on a quad Fabry-Perot etalon (FPE) is proposed that is capable of accurately detecting wind speed, as well as temperature and aerosol from 0.2 to 60km altitude. The structure of lidar is designed and its measurement principle is analyzed. One of the four FPEs, i.e. FPE-L is used for locking and measuring the outgoing laser frequency, and the other three, i.e. FPE-1, -2 and -3 form a three-stage FPE. The first-stage FPE (FPE-1) can effectively filter out Mie backscattering signal, thereby suppressing its effects on wind measurement and measuring the aerosol backscatter ratio as well. The transmission spectra of the second- and third-stage FPEs (FPE-2,-3) form double edge for simultaneous wind and temperature measurements by using Rayleigh backscattering signal. The parameters of the quad FPE are optimized. The FWHM and relative peak position of FPE-1,-2,-3,-L are 0.6, 1.2, 1.2, 0.6GHz and 0, -1, 1, 0.3GHz, respectively. The performance of the proposed lidar is simulated and results show that for 0.3WSr-1m-2nm-1@355nm sky brightness, by using a 350mJ pulse energy, 50Hz repetition frequency laser and a 0.8m aperture telescope, with temporal resolution of 2min@0.2∼20km, 20min@20∼60km and vertical resolution of 45m@0.2∼10km, 90m@10∼ 20km, 180m@20∼40km, 1km@40∼60km, the measurement errors of temperature, aerosol backscattering ratio and vertical wind speed are below 5.3K, 3.0×10-3, 1.1m/s in nighttime and below 14.6K, 8.1×10-3, 2.5m/s in daytime from 0.2 to 60km altitude; the measurement error of two other orthogonal LOS wind speed with fixed zenith angle of 25.8° is below 1.3m/s in nighttime and 3.5m/s in daytime within the LOS wind speed dynamic range of ±50m/s from 0.2 to 60km altitude.