Fabry–Perot etalon-based ultraviolet high-spectral-resolution lidar for tropospheric temperature and aerosol measurement

Abstract

The 355-nm ultraviolet high-spectral-resolution technique based on a triple Fabry–Perot etalon (FPE) for simultaneous high-accuracy measurement of tropospheric temperature and aerosol is proposed. The detection principle is analyzed and the whole structure of lidar system is designed. The parameters of the triple FPE-labeled FPE-1, FPE-2 and FPE-L are optimized in detail. FPE-1, FPE-2 and FPE-L are used for measuring aerosol and separating Rayleigh signal from Mie signal, for measuring temperature and for frequency locking, respectively. The performance simulation of the proposed lidar system showed that the measurement errors of temperature and backscatter ratio are below 2 K and 0.17% at 8 km and below 4 K and 0.39% at 12 km with 30-m range resolution and 1-min integration time using a 48 mJ pulse energy and 20 Hz repetition rate laser and a 25-cm telescope. The influence of Mie signal contamination on temperature measurement mainly depends on the relative Mie rejection factors of the two channels for temperature measurement, which are 4.2 and 10.4% of our proposed system at 270 K and the corresponding temperature deviation is 1 K with backscatter ratio of 10 and Rayleigh photoelectrons of 105. Assuming the same number of total photoelectrons received, the backscatter ratio and temperature measurement accuracies of our proposed lidar are 4.16–22.58 and 2.07–2.76 times, respectively, that of the traditional dual-pass multi-cavity-FPE-based HSRL at temperature of 220–290 K and backscatter ratio of 1–10.