Journals >Journal of Atmospheric and Environmental Optics
Contents
2009
Volume: 4 Issue 1
13 Article(s)
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Research Article
Optical Measurement of Temperature Gradient in the Unhomogeneous Atmospheric Surface Layer
Zong-yong ZENG, Feng-gan XIAO, Jian-guo LIU, and Wen-qing LIU
Equations are obtained which describe the trajectory of light ray through the unhomogeneous atmospheric surface layer when the three-dimensional equation of ray is analyzed and simplified. The equations can be used as the base of optical measurement. Characteristics of temperature gradient in the surface layer are discEquations are obtained which describe the trajectory of light ray through the unhomogeneous atmospheric surface layer when the three-dimensional equation of ray is analyzed and simplified. The equations can be used as the base of optical measurement. Characteristics of temperature gradient in the surface layer are discussed. The integral which relates the refraction angle and its variable to the temperature gradient based on the geometry of ray curve and the weighting function of temperature gradient are discussed. It was shown that the area-averaged value can not be obtained by means of unilateral measurement of angle when the distribution of temperature gradient is unhomogeneous and symmetrical. A bidirectional optical system is necessary. It was shown that the area-averaged temperature profile also can not be obtained by means of a system with multi-laser sources in the unhomogeneous atmospheric surface layer..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 1 (2009)
Atmospheric Propagation Characteristics of Medium-range or Short-range Laser Rangefinders Close to Ground
Wen-xue LI, Sheng-yi XIONG, and Ji-yu XING
Atmospheric effects including atmosphere absorption, scattering and turbulence in the process of laser ranging are studied, and atmospheric propagation characteristics of common 1.06 [EQUATION]m medium-range or short-range laser ranging close to ground are analyzed. It provides reference for design and application of lAtmospheric effects including atmosphere absorption, scattering and turbulence in the process of laser ranging are studied, and atmospheric propagation characteristics of common 1.06 [EQUATION]m medium-range or short-range laser ranging close to ground are analyzed. It provides reference for design and application of laser rangefinders..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 8 (2009)
Property of Spatial Degree of Coherence of Partially Coherent Flat-topped Beams Through Atmospheric Turbulence
Qing-hua BU, Hai-yan WANG, and Xiang-yin LI
Based on the quadratic approximation of the Rytov’s phase structure function and the Huygens-Fresnel principle, propagation equation for the spatial degree of coherence of partially coherent flat-topped beams propagating in turbulence atmosphere is derived, and the properties of the spatial degree of coherence in turbuBased on the quadratic approximation of the Rytov’s phase structure function and the Huygens-Fresnel principle, propagation equation for the spatial degree of coherence of partially coherent flat-topped beams propagating in turbulence atmosphere is derived, and the properties of the spatial degree of coherence in turbulence atmosphere are investigated numerically. The result shows that properties of spatial degree of coherence of partially coherent flat-topped beams are determined by the refractive index structure constant of atmospheric turbulence, the beams’ relative length of the space-related, the order of flat-topped beams, transmission distance and location of the observation point in common. It also shows that the oscillatory behavior and phase singularities of the spatial degree of coherence may occur when partially coherent flat-topped beams propagates through atmosphere turbulence. But the oscillatory behavior becomes sweaker with atmosphere turbulence increasing, and the phenomena of the oscillatory behavior and phase singularities will disappear in the end..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 13 (2009)
Measurement and Comparison of Ozone, Temperature, Water Vapor,Aerosol and CO[EQUATION] at Summer Over Hefei
Guang-qiang FAN, Shun-xing HU, Jun XIE, Zhi-hai XU, Huan-ling HU, and Ying-jian WANG
It is important to monitor atmospheric parameters such as ozone concentration, relative humidity, aerosol backscattering coefficient, temperature, CO[EQUATION] concentration, and analyze the basic characteristics for building native atmospheric mode and establishing appropriate environment protection policy. These atmoIt is important to monitor atmospheric parameters such as ozone concentration, relative humidity, aerosol backscattering coefficient, temperature, CO[EQUATION] concentration, and analyze the basic characteristics for building native atmospheric mode and establishing appropriate environment protection policy. These atmospheric parameters can be measured by L625 multifunction lidar. Data measured with L625 lidar and data from MLS, radiosonde, DWL lidar, Raman lidar are compared. Results indicate that the parameters measuremed by L625 multifunction lidar is feasible and reliable. The atmospheric parameters are analyzed, and the basic characteristics at summer over Hefei are obtained..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 22 (2009)
BP Neural Network Model of the Equivalent Complex Refractive Index of Aerosol
Xiu-yong QI, Yin-bo HUANG, Shuai FANG, and Rui-zhong RAO
Based on the improved BP algorithm and Mie scattering theory, the nonlinear relation of wavelength, scattering coefficient, absorption coefficient and equivalent complex refractive index is developed. The BP neural network model of the equivalent refractive index of aerosol is also developed. The optical properties of Based on the improved BP algorithm and Mie scattering theory, the nonlinear relation of wavelength, scattering coefficient, absorption coefficient and equivalent complex refractive index is developed. The BP neural network model of the equivalent refractive index of aerosol is also developed. The optical properties of aerosol obtained from inversion refractive index, such as scattering coefficient, absorption coefficient, are in good agreement with measurement results..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 30 (2009)
Measurement of Ethane Spectrum with High Resolution near 1.65 m Based on TDLAS
Gui-shi WANG, Ting-dong CAI, Lei WANG, Wei-jun ZHANG, and Xiao-ming GAO
Based on tunable diode laser absorption spectroscopy (TDLAS) technology, combining a Herriot cell with optical length of 50 m, using a wave-length-meter to scale the positions of the lines, the positions and intensities of 71 ethane lines between 6039 cm[EQUATION] and 6054 cm[EQUATION] are precisely measured, and the mBased on tunable diode laser absorption spectroscopy (TDLAS) technology, combining a Herriot cell with optical length of 50 m, using a wave-length-meter to scale the positions of the lines, the positions and intensities of 71 ethane lines between 6039 cm[EQUATION] and 6054 cm[EQUATION] are precisely measured, and the minimum detection absorption intensity reaches 10[EQUATION] cm[EQUATION]/(molecule[EQUATION]cm[EQUATION]). Results and errors are analyzed in detail, which is very useful to carry on research of natural gas in further..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 38 (2009)
Infrared Radiometric Calibration Based on Frequency Conversion Technique
Jian-jun LI, Xiao-bing ZHENG, Yun-jun LU, and Xiang-qun XUE
An infrared radiometric calibration method with high precision is put forward based on the parametric conversion technique. The infrared signal radiation is mixed with higher frequency laser pump radiation in a nonlinear crystal, and the effect of parametric amplification occurs. The infrared radiation is converted to An infrared radiometric calibration method with high precision is put forward based on the parametric conversion technique. The infrared signal radiation is mixed with higher frequency laser pump radiation in a nonlinear crystal, and the effect of parametric amplification occurs. The infrared radiation is converted to visible radiation by using phase-matching technique. It is a method with absoluteness, so the higher infrared calibration precision could be reached. Blackbody is considered as model of infrared radiation, the feasibility of infrared radiation calibration by parametric conversion technique is analyzed theoretically. The new calibration technique will be widely used in the field of communication, night vision and remote sensing..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 46 (2009)
Analysis of Influencing Factor for Inversion of Turbulence Profile Based on MASS
Zhi-bo NI, Hong-hua HUANG, Yin-bo HUANG, and Rui-zhong RAO
Influences of aperture size and hierarchical model of turbulence on weighting functions are discussed. Based on these, using singular value decomposition, vertical turbulence profiles for different aperture sizes and hierarchical models of turbulence are inversed and influences of hierarchical models of turbulence and Influences of aperture size and hierarchical model of turbulence on weighting functions are discussed. Based on these, using singular value decomposition, vertical turbulence profiles for different aperture sizes and hierarchical models of turbulence are inversed and influences of hierarchical models of turbulence and aperture sizes on inversion results are discussed. The results indicate that vertical turbulence profiles are more reasonable based on weighting functions of smaller aperture ratio and geometric hierarchical model of turbulence..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 51 (2009)
Intra-pulse Spectroscopy Based on Room-temperature Pulsed Quantum Cascade Laser
Min WANG, Yu-jun ZHANG, Wen-qing LIU, Rui-feng KAN, Zhen-yi CHEN, Yuan-yuan TANG, and Jian-guo LIU
The intra-pulse spectroscopy based on a room-temperature distributed-feedback pulsed quantum cascade (QC) laser is introduced. The thermal chirp during a long excitation pulse is applied to a quantum-cascade laser centered at 7.85 [EQUATION]m, which is used for fast wavelength scanning. The laser spectra under differenThe intra-pulse spectroscopy based on a room-temperature distributed-feedback pulsed quantum cascade (QC) laser is introduced. The thermal chirp during a long excitation pulse is applied to a quantum-cascade laser centered at 7.85 [EQUATION]m, which is used for fast wavelength scanning. The laser spectra under different working parameters are compared and analyzed, with the aim of finding out the optimal working parameters of laser. The N[EQUATION]O absorption spectra centered at 1273.7 cm[EQUATION] are also obtained..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 57 (2009)
Design for Spectral Data Acquisition System Based on NMOS Linear Image Sensor
Tao WANG, and Jian BAO
A spectral data acquisition system is designed based on NMOS linear image sensor and micro controller unit (MCU) technology. The hardware and operating principle of this system are introduced, and the structure, principle and characteristics of S3924-512Q image sensor are analyzed in detail. Data acquisition of spectraA spectral data acquisition system is designed based on NMOS linear image sensor and micro controller unit (MCU) technology. The hardware and operating principle of this system are introduced, and the structure, principle and characteristics of S3924-512Q image sensor are analyzed in detail. Data acquisition of spectral signal is realized by A/D conversion controlled by PIC16F877A MCU, and flowchart of the program is given. Using this system, spectral acquisition of the specific band with high precision is achieved..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 63 (2009)
Ground Clutter Suppression for Wind Profile Radar
De-bao DONG, Ning-quan WENG, Gang SUN, and Li-ming XIAO
Wind profile radar is an effective tool for detecting atmospheric wind field and turbulence. Its echo is liable to be interfered by ground clutter and becomes complicated. To improve detection precision of radar, ground clutter suppression is an important part of radar signal and spectrum processing. Current method of Wind profile radar is an effective tool for detecting atmospheric wind field and turbulence. Its echo is liable to be interfered by ground clutter and becomes complicated. To improve detection precision of radar, ground clutter suppression is an important part of radar signal and spectrum processing. Current method of ground clutter suppression is introduced and its deficiency is analyzed, and the characteristics of ground clutter and radar atmospheric echo spectrum in frequency domain are investigated. Combined with gradient analysis of atmospheric echo spectrum, the method for suppressing ground clutter is described based on Gaussian least square quadratic fitting to the uncontaminated atmospheric echo spectrum. Results show that it is feasible to suppress ground clutter..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 69 (2009)
Analysis of Backscattering Signal for a Ceilometer
Zhen-yi CHEN, Wen-qing LIU, Yu-jun ZHANG, Jun-feng HE, Jun RUAN, and Chun-guang ZHANG
The optimal wavelength detecting the height of cloud is analyzed. Profiles of molecule extinction coefficient and aerosol extinction coefficient, which is necessary for signal estimation, are presented. Calculation for the geometric overlap factor with the existing slit diaphragm in a co-axial lidar is also given. BaseThe optimal wavelength detecting the height of cloud is analyzed. Profiles of molecule extinction coefficient and aerosol extinction coefficient, which is necessary for signal estimation, are presented. Calculation for the geometric overlap factor with the existing slit diaphragm in a co-axial lidar is also given. Based on the specific features and lidar equation, simulations of the backscattering power and impact on the signal to noise ratio are discussed when the emitting power, emitting pulse numbers and width of the filter change. Results are meaningful for discussing the ceilometer’s detecting capability, and it offers theoretical basis to determine technical parameters of a ceilometer..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 75 (2009)
[in Chinese]
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 1, 1 (2009)
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