Investigation Of Detection Method Of Atmospheric Temperature By Using High Spctral Resolution Lidar With Polarizaion Filter At Daytime

Atmospheric temperature is one of the basic physical quantities that describe the state of the atmosphere and meteorological changes,which has important reference significance for observing global warming,urban heat island phenomena,and the characteristics of moisture absorption and growth of particulate matter.As an active remote sensing detection method,high spectral resolution lidar has the characteristics of high temporal and spatial resolution and easy to achieve day-time observation,which is considered to be an important means for accurately and continuously detecting atmospheric temperature,atmospheric wind and aerosols.This paper focuses on the method of detecting atmospheric temperature by using high spectral resolution lidar.In order to use low-pulse energy and small-aperture telescopes to achieve high-signal-to-noise ratio atmospheric temperature detection at daytime,we proposes a high spectral resolution lidar spectroscopic system based on polarization.High spectral resolution lidar spectroscopic system based on polarization uses three Fabry-Perot etalons as filters to invert the atmospheric temperature by detecting the change in signal intensity transmitted through the filters.Compared with the traditional high spectral resolution lidar spectroscopic system that divides the intensity of the return signal into different filter channels,this system combines the polarization characteristics of laser light with the transmission and reflection spectrum of the Fabry-Perot etalon to makes full use of the intensity of the return signal,that is to say,the intensity of the return signal is not lost when the beam is incident on each filter channel.In addition,the solar background light and the Mie scattering signal is suppressed by using the optics of polarized scheme and improves the signal-to-noise ratio and daytime detection capabilities of the high spectral resolution lidar.In addition,Stokes vector and Mueller matrix are used to calculate and analyze the detection performance of the spectroscopic system based on polarization.A high spectral resolution lidar spectroscopic system based on polarization is built,and the incident angle,divergence angle and bandwidth of the filters are adjusted and optimized,then the offset of the center frequency of the transmission spectrum of the three Fabry-Perot etalons was adjusted and calibrated.Detection performance of the spectroscopic system based on polarization is evaluated through the signal-to-noise ratio simulation.Compared with the traditional high spectral resolution lidar system under the same conditions of system parameters,the simulation results show that the effective detection height of the system is 3km(SNR=100)during the day,and the detection height is increased by 2.5 times,the detection height is 4.5km(SNR=100),and the detection height is increased by 2 times.Finally,an observation experiment was carried out on the atmospheric temperature in a local area of Xi'an.In detection experiments of atmospheric temperature,the detection height is 2.5 km during the day and 4 km at night by using the pulsed energy of 50 mJ and telescope diameter of 250 mm.The results of high spectral resolution lidar spectroscopic system based on polarization are in good agreement with the radiosonde data.Finally,high spectral resolution lidar spectroscopic system based on polarization uses low pulse energy and small-aperture telescopes to achieve a high signal-to-noise ratio of atmospheric temperature detection at daytime.