Differential Absorption Lidar Atmospheric Pressure Detection Technology And Experimental Observation

Atmospheric pressure profile plays an important role in atmospheric dynamics and weather numerical model.It is an important basis for the establishment of weather analysis system and weather forecast.The detection of atmospheric pressure profile mainly adopts the method of releasing sounding balloons,and the spatial resolution and temporal resolution are very low.Lidar is a potential instrument for detecting atmospheric meteorological elements with high spatial-temporal resolution.In recent years,it has been widely used and developed rapidly,lidar can also obtain the atmospheric pressure profile with high spatial-temporal resolution.In this paper,the technology of detecting atmospheric pressure by differential absorption lidar is studied.Based on the differential absorption lidar equation,this paper gives the differential absorption lidar atmospheric pressure detection mechanism and inversion algorithm.Combined with the oxygen A-band absorption spectral properties,atmospheric model and HITRAN database,the differential absorption lidar atmospheric pressure detection inversion numerical model is established,and the atmospheric pressure values at different altitudes are obtained;By analyzing the error sources that affect the system performance,such as atmospheric parameters and optical parameters,a comprehensive analysis and selection model for the detection wavelength of the differential absorption lidar system is established.The on-line and off-line wavelengths selected through comprehensive evaluation are 759.804nm and 759.463nm respectively.Based on the existing conditions in the laboratory,the optimal design of the differential absorption lidar atmospheric pressure detection experimental system is carried out.The source output by OPO.T he divergence angle of the outgoing laser is modulated to 0.3mrad.The dual wavelength beam combining design is carried out for the outgoing on and off laser wavelengths.In addition,for the reception of the lidar echo signal emitted by the combined beam,a 350mm Cassegrain telescope,a photomultiplier tube and an optical filter are used to carry out the spectral design of the receiving system.A differential absorption lidar atmospheric pressure detection experimental system is built,and the experimental observations are carried out.The effective experimental echo data are obtained.The atmospheric pressure inversion and the results are compared and analyzed.A combined denoising algorithm of adaptive morphological filtering and parameter optimized variational mode decomposition(AMF-POVMD)is established by means of comparative analysis.T he atmospheric pressure profile of 0～6km is obtained by using the algorithm to process data and inverse.The comparative analysis results show that the error in comparison with the established atmospheric numerical model is less than 7hPa;In comparison with sounding data,it is less than 8h Pa in the altitude range below 4km,which verifies the feasibility of the system design.