The multilongitudinal mode[MLM]high-spectral-resolution lidar[HSRL]based on the Mach±Zehnder interferometer[MZI]is constructed in Xi’an for accurate measurements of aerosol optical properties.The critical requir...The multilongitudinal mode[MLM]high-spectral-resolution lidar[HSRL]based on the Mach±Zehnder interferometer[MZI]is constructed in Xi’an for accurate measurements of aerosol optical properties.The critical requirement of the optimal match between the free spectral range of MZI and the longitudinal mode interval of the MLM laser is influenced by the laboratory temperature,pressure,and vibration.To realize the optimal separation of aerosol Mie scattering signals and molecular Rayleigh scattering signals excited by the MLM laser,a self-tuning technique to dynamically adjust the optical path difference[OPD]of the MZI is proposed,which utilizes the maximum ratio between the received power of the Mie channel and Rayleigh channel as the criterion of the OPD displacement.The preliminary experiments show the feasibility of the MLM-HSRL with self-tuning MZI and the stable performance in the separation of aerosol Mie scattering signals and molecular Rayleigh scattering signals.展开更多
Lidar ratios and AngstrOm exponents of continental,maritime,and desert aerosols were calculated to evaluate the effects of aerosol composition on these parameters.Their correlation was assessed using correlation analy...Lidar ratios and AngstrOm exponents of continental,maritime,and desert aerosols were calculated to evaluate the effects of aerosol composition on these parameters.Their correlation was assessed using correlation analysis and curve fitting.The Pearson correlation coefficient between the lidar ratio and the AngstrOm exponent was larger than 0.95 in all cases.We verified the reliability of the Pearson correlation coefficient using the significance test.The relationship between the lidar ratio and the Angstrom expo- nent of continental aerosol can be described by a cubic polynomial model;thus,the function relation between the change in lidar ratios at different laser wavelengths depends on the fitting coefficients and the AngstrOm exponent.The relationship between the lidar ratio and the AngstrOm exponent of both maritime and desert aerosols can be described by a linear model.In these aerosols,the linear change in lidar ratios at different laser wavelengths remains unaffected by the AngstrOm exponent.The changes in the lidar ratio in maritime aerosol at 355nm and 532nm are -0.7times and -0.18times that at 1064nm, respectively.For desert aerosol,the changes in the lidar ratio at 355nm and 532nm are 0.37 times and 1.88times that at 1064nm,respectively.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42175149 and 41775035)the China-CEEC Joint Higher Education Project(No.202017)the Natural Science Foundation of Shaanxi Province,China(No.2020JM-445)。
文摘The multilongitudinal mode[MLM]high-spectral-resolution lidar[HSRL]based on the Mach±Zehnder interferometer[MZI]is constructed in Xi’an for accurate measurements of aerosol optical properties.The critical requirement of the optimal match between the free spectral range of MZI and the longitudinal mode interval of the MLM laser is influenced by the laboratory temperature,pressure,and vibration.To realize the optimal separation of aerosol Mie scattering signals and molecular Rayleigh scattering signals excited by the MLM laser,a self-tuning technique to dynamically adjust the optical path difference[OPD]of the MZI is proposed,which utilizes the maximum ratio between the received power of the Mie channel and Rayleigh channel as the criterion of the OPD displacement.The preliminary experiments show the feasibility of the MLM-HSRL with self-tuning MZI and the stable performance in the separation of aerosol Mie scattering signals and molecular Rayleigh scattering signals.
基金National Natural Science Foundation of China grants:No.61405158and No.41627807.
文摘Lidar ratios and AngstrOm exponents of continental,maritime,and desert aerosols were calculated to evaluate the effects of aerosol composition on these parameters.Their correlation was assessed using correlation analysis and curve fitting.The Pearson correlation coefficient between the lidar ratio and the AngstrOm exponent was larger than 0.95 in all cases.We verified the reliability of the Pearson correlation coefficient using the significance test.The relationship between the lidar ratio and the Angstrom expo- nent of continental aerosol can be described by a cubic polynomial model;thus,the function relation between the change in lidar ratios at different laser wavelengths depends on the fitting coefficients and the AngstrOm exponent.The relationship between the lidar ratio and the AngstrOm exponent of both maritime and desert aerosols can be described by a linear model.In these aerosols,the linear change in lidar ratios at different laser wavelengths remains unaffected by the AngstrOm exponent.The changes in the lidar ratio in maritime aerosol at 355nm and 532nm are -0.7times and -0.18times that at 1064nm, respectively.For desert aerosol,the changes in the lidar ratio at 355nm and 532nm are 0.37 times and 1.88times that at 1064nm,respectively.
