Using the Differential Absorption Lidar (DIAL) technique, two types of approaches, namely, reflection from retroreflector / topographic target and backscatter from atmosphere, are available for studying remotely the a...Using the Differential Absorption Lidar (DIAL) technique, two types of approaches, namely, reflection from retroreflector / topographic target and backscatter from atmosphere, are available for studying remotely the atmospheric NO, concentration. The Argon ion lidar system at the Indian Institute of Tropical Meteorology (IITM), Pune, India has been used for the measurements by following both the path-averaged and range-resolved approaches. For the former, a topographic target (hill) is used for determining path-averaged surface concentration. In the latter, spectral properties of atmospheric attenuation is used for making range-resolved measurements in the surface layer. The results of the observations collected by following both approaches are presented. The average surface NO2 concentration was found to vary between 0.01 and 0.105 ppm and the range-resolved measurements exhibited higher values suggesting treatment of the lidar data for scattering and extinction effects due to atmospheric aerosols and air molecules, and atmospheric turbulence. Certain modifications that are suggested to the experimental set-up, data acquisition and analysis to improve the measurements are briefly described.展开更多
In this paper, the effect of scintillation on system SNR is discussed. Atmospheric scintillation is described and log amplitude variance in slant path is given. In addition, the simulations of system SNR at different ...In this paper, the effect of scintillation on system SNR is discussed. Atmospheric scintillation is described and log amplitude variance in slant path is given. In addition, the simulations of system SNR at different propagation path and different height are obtained. The results from simulation show that atmospheric scintillation has an important effect on SNR of DIAL system, especially near the ground.展开更多
Based on Raman-shifted wavelengths of D2 and CHr pumped by third harmonic of Nd:YAG laser, a differential absorption lidar was presented in this paper and had been constructed for probing environmental NO2 concentrati...Based on Raman-shifted wavelengths of D2 and CHr pumped by third harmonic of Nd:YAG laser, a differential absorption lidar was presented in this paper and had been constructed for probing environmental NO2 concentration. NO2 experimental measurements were carried out at Anhui Institute of Optics and Fine Mechanics in Hefei. Some NO2 measurement results were given and discussed.展开更多
In this paper the effects of aerosol on tropospheric ozone measurements by three-wavelength (266-289-308nm) dual differential absorption lidar (DIAL) and two-wavelength (266-289 nm and 266-308 nm) DIAL are simulated.B...In this paper the effects of aerosol on tropospheric ozone measurements by three-wavelength (266-289-308nm) dual differential absorption lidar (DIAL) and two-wavelength (266-289 nm and 266-308 nm) DIAL are simulated.By using the two kinds of DIAL.vertical profiles of ozone density from 2 to 3.6 km altitude range are measured.Both simulation and observation results show that the three-wavelength dual-DIAL method is more effective to reduce the effects of aerosol than the two-wavelength DIAL method.Therefore,accurate ozone density distributions can be retrieved by the three wavelength dual DIAL method.展开更多
A single-frequency pulsed holmium-doped yttrium lithium fluoride(Ho:YLF)amplifier pumped by a Tm-doped fiber laser was demonstrated.The seed was an injection-seeded Q-switched Ho:YLF laser.The output energy from the s...A single-frequency pulsed holmium-doped yttrium lithium fluoride(Ho:YLF)amplifier pumped by a Tm-doped fiber laser was demonstrated.The seed was an injection-seeded Q-switched Ho:YLF laser.The output energy from the singlefrequency pulsed amplifier was 24.2 mJ,with a pulse width of 250 ns at a pulse repetition frequency(PRF)of 100 Hz.The energy stability during 30 min was improved to 1%after the single-frequency pulsed Ho:YLF laser was amplified.The line width of the single-frequency pulsed spectrum of the Ho:YLF amplifier was 2.81 MHz.The single-frequency pulsed Ho:YLF amplifier can be applied to differential absorption lidar(DIAL),since its output spectrum is around the P12 CO2 absorption line.展开更多
文摘Using the Differential Absorption Lidar (DIAL) technique, two types of approaches, namely, reflection from retroreflector / topographic target and backscatter from atmosphere, are available for studying remotely the atmospheric NO, concentration. The Argon ion lidar system at the Indian Institute of Tropical Meteorology (IITM), Pune, India has been used for the measurements by following both the path-averaged and range-resolved approaches. For the former, a topographic target (hill) is used for determining path-averaged surface concentration. In the latter, spectral properties of atmospheric attenuation is used for making range-resolved measurements in the surface layer. The results of the observations collected by following both approaches are presented. The average surface NO2 concentration was found to vary between 0.01 and 0.105 ppm and the range-resolved measurements exhibited higher values suggesting treatment of the lidar data for scattering and extinction effects due to atmospheric aerosols and air molecules, and atmospheric turbulence. Certain modifications that are suggested to the experimental set-up, data acquisition and analysis to improve the measurements are briefly described.
文摘In this paper, the effect of scintillation on system SNR is discussed. Atmospheric scintillation is described and log amplitude variance in slant path is given. In addition, the simulations of system SNR at different propagation path and different height are obtained. The results from simulation show that atmospheric scintillation has an important effect on SNR of DIAL system, especially near the ground.
基金This work was supported by the National 863 High Technology Research and Development Projects,S,
文摘Based on Raman-shifted wavelengths of D2 and CHr pumped by third harmonic of Nd:YAG laser, a differential absorption lidar was presented in this paper and had been constructed for probing environmental NO2 concentration. NO2 experimental measurements were carried out at Anhui Institute of Optics and Fine Mechanics in Hefei. Some NO2 measurement results were given and discussed.
基金This work is supported by the National High Technology Research and Development Plan and National Natural Science Foundation of China(49775258).
文摘In this paper the effects of aerosol on tropospheric ozone measurements by three-wavelength (266-289-308nm) dual differential absorption lidar (DIAL) and two-wavelength (266-289 nm and 266-308 nm) DIAL are simulated.By using the two kinds of DIAL.vertical profiles of ozone density from 2 to 3.6 km altitude range are measured.Both simulation and observation results show that the three-wavelength dual-DIAL method is more effective to reduce the effects of aerosol than the two-wavelength DIAL method.Therefore,accurate ozone density distributions can be retrieved by the three wavelength dual DIAL method.
基金supported by the National Natural Science Foundation of China(No.51572053)。
文摘A single-frequency pulsed holmium-doped yttrium lithium fluoride(Ho:YLF)amplifier pumped by a Tm-doped fiber laser was demonstrated.The seed was an injection-seeded Q-switched Ho:YLF laser.The output energy from the singlefrequency pulsed amplifier was 24.2 mJ,with a pulse width of 250 ns at a pulse repetition frequency(PRF)of 100 Hz.The energy stability during 30 min was improved to 1%after the single-frequency pulsed Ho:YLF laser was amplified.The line width of the single-frequency pulsed spectrum of the Ho:YLF amplifier was 2.81 MHz.The single-frequency pulsed Ho:YLF amplifier can be applied to differential absorption lidar(DIAL),since its output spectrum is around the P12 CO2 absorption line.
