Research On Laser Lidar Detection Technology Of Boundary Layer Temperature And Humidity Profile

Temperature and humidity play important roles in many chemical and physical processes of the atmosphere,and are also very important meteorological parameters.In order to realize the detection of temperature and humidity profiles near the boundary layer,a lidar system for temperature and humidity profiles based on a high-linear-resolution spectroscopic optical system was developed,and pure rotational Raman signals were corrected.The main research contents include the following aspects:(1)A lidar system suitable for temperature and humidity profiles at boundary-layer height was developed.Temperature profiles were using vibrational Raman signals of nitrogen and vapor.Meanwhile,the system detected Rayleigh-Mie scattering signals at 532 nm wavelength.(2)A low blind region was designed based on a dual-fiber optical dual field-of-view.The design and consideration of the main components of the lidar system for temperature and humidity profiles near the boundary layer were provided in this paper.In order to meet the requirements of detection in the small low region of the boundary layer,a optical system based on dual-fiber optical dual field-of-view was proposed.The blind region could be suppressed to 60 meters,meeting the requirements of detection in the blind region.(3)A high-linear-resolution spectroscopic optical system for measuring temperature was developed.Pure rotational Raman for the measurement of temperature needed a linear resolution of 0.1 nm/millimeter.In this paper,the spherical aberrations in the edge imaging were corrected using aspherical lenses and long-focus focusing lenses based on double-grating,realizing the extraction of continuous spectrum and the high-linear-resolution detection of the whole system.(4)A high-precision spectroscopic optical system for measuring vapor was developed.In this paper,a high-density grating was used to split the light,with the resolution of vibrational Raman spectrum reaching 0.66 nm.A multi-channel and multi-band debugging light source was developed.On this basis,the alignment of the spectroscopic optical system was completed.The coaxial adjustment of the lidar transceiver optical system for temperature and humidity profiles at the boundary layer was completed,and the rationality of this system was verified.(5)The inversion algorithm and calibration method for temperature and humidity were studied.The rejection ratio of Rayleigh-Mie scattering signals of each channel of the spectroscopic optical system for measuring temperature was measured quantitatively,the method of eliminating residual Mie scattering interference from pure rotational Raman signals was studied,the temperature and humidity profiles were calibrated,and error analysis was performed for the measurement results.