Research On Method And System Of Absolute Detection Of Atmospheric Temperature By Using High Spectral Resolution Lidar Based On Rayleigh Scattering

Atmospheric temperature is a key parameter for studying atmospheric sciences,which is of great significance for studying atmospheric conditions and meteorological changes.Atmospheric temperature can provide an important reference for predicting global warming and urban heat island effects.As an active remote sensing method,high spectral resolution lidar has high temporal and spatial resolution and is easy to detect during the day,which has gradually become one of the important methods of atmospheric temperature detection by extracting signals with ultra-narrowband filters to achieve fine detection of atmospheric physical quantities.Aiming at the high spectral resolution lidar that needs a correction program when inverting the change of atmospheric temperature and does not consider the insufficiency of Brillouin scattering,this paper proposes a high spectral resolution lidar based on the Rayleigh-Brillouin scattering envelope spectrum that a method for absolute detection of atmospheric temperature.Spectroscopic system uses a scanning solid cavity Fabry-Perot interferometer as the core device,and the cavity medium uses a double-ring electrode potassium dideuterium phosphate electro-optic crystal.Based on the electro-optic effect of the crystal,the crystal is controlled.The magnitude of the applied electric field causes the length of the optical cavity to change,and the resonant frequency of the cavity is changed.The sweep voltage step length and the frequency positions of the four discrete points are determined.By detecting the intensity of the light which transmitted through the Fabry-Perot interferometer,the Rayleigh-Brillouin scattering model is used to decouple the envelope spectrum to obtain an independent Rayleigh scattering spectrum,and then according to the dependence of the Rayleigh scattering spectrum width and atmospheric temperature inversion to obtain the absolute value of the atmospheric temperature.Through the comparison of system simulation and theoretical analysis,the solid cavity Fabry-Perot interferometer is determined and used to continuously change the cavity to realize the Rayleigh-Brillouin scattering spectrum scanning.Secondly,the scanning frequency interval of the Rayleigh-Brillouin spectral line and the electro-optic crystal setting parameters are determined,and the detection performance of the system is simulated and analyzed with various parameters.A high spectral resolution lidar spectroscopic system is built,and the filtering performance of the system is adjusted and optimized.Under the detection conditions of pulse energy of 80mJ and telescope diameter of 250mm,the Rayleigh-Brillouin decoupling model is used to achieve day-time atmospheric temperature profile detection with a detection height of 1.5km during the day and a detection height of 2km at night.The detection results of lidar are consistent with the radiosonde data,which verifies that the high spectral resolution lidar system based on the scanning solid cavity Fabry-Perot interferometer can effectively achieve atmospheric temperature detection by using the Rayleigh-Brillouin decoupling model.This method is not only suitable for detecting atmospheric temperature,but also for detecting the physical characteristics of aerosols and atmospheric wind speed,providing a reference for the observation of various weather changes and physical effects.