Design And Implementation Of Multi Parameter Lidar System For Meterological Observation

The changes in atmospheric aerosol content,atmospheric temperature and relative humidity in the atmosphere below troposphere will directly affect human production and life,and these meteorological parameters can be used to predict weather changes and environmental changes.Therefore,the detection of meteorological parameters is particularly important.There are many detection methods for meteorological parameters.Lidar as an effective detection method has been widely used.At present,the lidar system used to detect meteorological parameters is a discrete detection system used in laboratory conditions.The detection system built in the laboratory is difficult to realize all day detection and easily affected by many environmental factors,such as the temperature,vibration and impact level of the environment.Therefore,it is necessary to design a mobile lidar system with stable performance and can be used for all day and continuous observation.Based on the previous theoretical research and experimental system,we designed a meteorological lidar system.The main research contents of the thesis include:Based on the theory of Mie scattering and Raman scattering,combined with the lidar technology,using the modular design concept,the structure design and optimization of the meteorological observation lidar system was carried out,mainly for the ejection subsystem,the receiving subsystem,the photon splitting system and the photoelectric detection subsystem in the lidar system.The finite element analysis method is used to analyze the mechanical properties of the designed structure,and the temperature characteristics and frequency characteristics of the optical structure are mainly analyzed.The temperature characteristic analysis is to determine the change of the mechanical properties of the structure under the change of the ambient temperature,and the frequency characteristics analysis is to assess whether the equipment can meet the anti-vibration requirements of secondary roads when moving the equipment.Based on the spectrum extracted from the grating spectrometer,the spectrometer is debugged using the designed adjusting mechanism,the coaxial adjustment of lidar is done by using the reflector to make a rough adjustment to the coaxial system.On this basis,the system coaxial is adjusted fine according to the echo signal.In the end,the subsystem was integrated into a set of systems using a stable frame structure,based on the design requirements of the observations of aerosol content,atmospheric temperature,and relative humidity throughout the day,the frame structure was built.The constructed weather observation lidar system is used to carry out all-day observations.Based on the analysis and processing of experimental observation data,the stability of the system is judged based on the existence of relatively stable nitrogen signals in the atmosphere.The system has been tested for ten months.Under different weather conditions,the detection height of nitrogen channels can reach about 5km,and the system performance is stable.Under this condition,the system can detect all the parameters of the system.The detection results show that the designed system can detect the aerosol signal and the rotational Raman temperature signal all day,and the height of detection is better than 5km,vibration Raman measured the water vapor signal in daytime at a height of 2 km and at night a detection height of 3 km.