Journals >Journal of Atmospheric and Environmental Optics
Contents
2009
Volume: 4 Issue 3
12 Article(s)
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Research Article
Measurement and Study of Aerosol Optical properties over the North Yellow Sea of China in Fall
Wen DONG, Wen-Zhong CHEN, and Yi LIU
Dong Fang Hong No.2, a scientific survey ship belonging to Ocean University of China, has a voyage on the north Yellow Sea of China during the period from 14 th to 25 th in October of 2007 . The aim for this sailing is to attain aerosol optical properties data in that sea area. During the voyage, POM01-MKII, a seven baDong Fang Hong No.2, a scientific survey ship belonging to Ocean University of China, has a voyage on the north Yellow Sea of China during the period from 14 th to 25 th in October of 2007 . The aim for this sailing is to attain aerosol optical properties data in that sea area. During the voyage, POM01-MKII, a seven bands auto sky radiometer made in Japan, was used in order to measure the precise aerosol optical data and it got lots of true measurement data. After dealing with the data, aerosol optical thickness(AOT), single scattering albedo(SSA), and columnar volume spectrum were obtained. The results showed that the value of AOT at 500 nm is less than 0.36 and the value at 870 nm is less than 0.15 when it has no cloud. Under the situation of fog or haze, the value of AOT is approximate 5 times bigger than that of without cloud; seeing from SSA, aerosol lies in absorption over the North Yellow Sea and the rule is that the nearer the distance to the bank is, the stronger the absorption is; the further the distance to the bank is, the weaker the absorption is; seeing from columnar volume spectrum, accumulation particle content from land has a largely relation with the absorption of aerosol..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 3, 161 (2009)
Numerical Simulation of Phase Screen Distorted by Atmospheric Turbulence Based on Fractal Theory
Hong-ping LI, Chuan-zhong YAN, and Zhi-li HUA
Accurately simulating the effect of atmospheric turbulence on the laser beams will improve the imaging ability of practical synthetic aperture ladar. A formalism to model the phase screen(PS) distorted by atmospheric turbulence based on fractal theory is provided. The random midpoint motion(RMM) algorithm is introducedAccurately simulating the effect of atmospheric turbulence on the laser beams will improve the imaging ability of practical synthetic aperture ladar. A formalism to model the phase screen(PS) distorted by atmospheric turbulence based on fractal theory is provided. The random midpoint motion(RMM) algorithm is introduced and used to simulate the phase screens corresponding to Kolmogorov and non-Kolmogorov turbulence respectively. Simulation accuracy evaluation is carried out by comparing the phase structure function and the theoretical results. Power spectrum method and structure function method are also used. Results show that RMM algorithm can give a better approximation to the theoretical value..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 3, 171 (2009)
Research on the Influence of Marine Atmospheric Turbulence to the Performance of Laser Communication System
Dong CHEN, Hong-gang LI, Zhi-bo NI, and Wei-yu Lü
Light intensity fluctuation in the cross-section caused by atmospheric turbulence increases the bit error rate(BER) of laser communication system. The effect is analyzed using the theory of light propagation in the atmosphere based on the Rytov approximation under the suitable assumptions of isotropic Kolmogolov spectrLight intensity fluctuation in the cross-section caused by atmospheric turbulence increases the bit error rate(BER) of laser communication system. The effect is analyzed using the theory of light propagation in the atmosphere based on the Rytov approximation under the suitable assumptions of isotropic Kolmogolov spectrum of turbulence, and the BER of laser communication system and atmospheric turbulence are combined in terms of signal detection theory. The analysis results turn out that, measured by BER, the effective distance of laser communication system shortens greatly along with the increasing of [EQUATION] under the environment of typical marine atmospheric turbulence, the effective distance is less than 2 km when [EQUATION] is equal to 5[EQUATION] m[EQUATION], and the distance even shortens to 1 km when [EQUATION] reaches 3[EQUATION] m[EQUATION]..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 3, 178 (2009)
Elementary Study on Turbulence Effects Resulted from Laser Propagation in the Atmosphere Based on the Stochastic Parallel Gradient Descent Algorithm
Ling FAN, Chun-hong QIAO, Xiao-xing FENG, Hui-min MA, and Cheng-yu FAN
Stochastic parallel gradient descent(SPGD) is a developing model-free optimum control algorithm in recent years, which is used for adaptive optics system for its advantages of inexpensive cost, beacon-free and so on. Laser propagation through atmosphere is simulated by the method of phase-screens, 61-elements deformablStochastic parallel gradient descent(SPGD) is a developing model-free optimum control algorithm in recent years, which is used for adaptive optics system for its advantages of inexpensive cost, beacon-free and so on. Laser propagation through atmosphere is simulated by the method of phase-screens, 61-elements deformable mirror is used as corrector, and the aberration caused by turbulence effects is corrected by SPGD algorithm. The numerical simulation results show that SPGD algorithm can be used in the adaptive optics system to correct the aberration caused by turbulence effects, the different perturbation amplitudes and gain coefficients are very important for the last corrected results, and the numerical simulation results on different propagation conditions are also shown..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 3, 183 (2009)
Laboratory Study on Heat Flux in the Convective Boundary Layer on Thermal Heterogeneous Surface
Xu-ping WU, Tao LUO, Ren-min YUAN, Chao LU, Yun-qian GUO, and Yi-bao LI
Convective water-tank is used to model the development of the convective boundary layer on thermal heterogeneous surface. Mosaic-like cover is put on the bottom of the water-tank to achieve thermal heterogeneity. In the convective boundary layer development, temperature profiles were measured on different surface regioConvective water-tank is used to model the development of the convective boundary layer on thermal heterogeneous surface. Mosaic-like cover is put on the bottom of the water-tank to achieve thermal heterogeneity. In the convective boundary layer development, temperature profiles were measured on different surface region and with which heat flux profiles are calculated. The results show that normalized heat flux profiles behave the non-linear characteristics, that is, the convex and concave features. Convex and concave features oscillate over time. This is obviously different from the case of homogeneous surface. From heat flux contour map, the oscillation of the overall average heat flux profiles is smaller than that of the uncovered and the covered surface regions. And the oscillation on the uncovered surface region has a higher frequency and greater amplitude. The results show that some turbulence structures of convective boundary layer on thermal heterogeneous surface are quite different from that on the homogeneous surface. The law of the parameters for homogeneous surface can not be applied alike for heterogeneous surface. The experimental results can provide useful reference for numerical simulation and field observations..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 3, 190 (2009)
A Method to Identify Case I and Case II Waters Based on the MODIS Images
Jin-ji MA, Hao CHEN, and Xin-hua JIANG
By statisically analyzing many MODIS images, an empirical algorithm is described, which is used to determine the case II water from the MODIS image. The algorithm takes advantage of the characteristic that the apparent reflectances of the case I and case II waters are the same in SWIR band, but considerably different iBy statisically analyzing many MODIS images, an empirical algorithm is described, which is used to determine the case II water from the MODIS image. The algorithm takes advantage of the characteristic that the apparent reflectances of the case I and case II waters are the same in SWIR band, but considerably different in the visible band. The empirical algorithm was applied to MODIS images over Bohai, China, the waters in Bohai were classified into two types: case I and case II. The results show that the proposed classification empirical algorithm is precise and effective..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 3, 201 (2009)
Light Spot Image’s Center of Mass Calculation Algorithm for Atmospheric Temperature Gradient Measurement
Yu HONG, Yi-huai LU, Zong-yong ZENG, and Feng-gang XIAO
The determination of the light spot center of mass is a key step in the refraction based measurement of atmospheric temperature gradient. An algorithm for the calculation of the light spot image’s center of mass is introduced. The calculation is used in the refraction based atmospheric temperature gradient measurement.The determination of the light spot center of mass is a key step in the refraction based measurement of atmospheric temperature gradient. An algorithm for the calculation of the light spot image’s center of mass is introduced. The calculation is used in the refraction based atmospheric temperature gradient measurement. An adaptive auto thresholding method is used in the algorithm which is suitable for various ambient environments. Experiment shows that the algorithm can be implemented easily and run in real-time; it is suitable to be used in the atmospheric temperature gradient measurement..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 3, 206 (2009)
Application of Atmospheric Correction Based on ATCOR3 Model
Jin-ji MA, and Hao CHEN
The algorithm of ATCOR3 was introduced. Then the algorithm was applied to correct two scene TM imageries of Tongling and Huangshan of Anhui Province. By the method of eye comparison and NDVI analyzing, the effect of the correction was analyzed. The results show that the influence of haze on images is effectively eliminThe algorithm of ATCOR3 was introduced. Then the algorithm was applied to correct two scene TM imageries of Tongling and Huangshan of Anhui Province. By the method of eye comparison and NDVI analyzing, the effect of the correction was analyzed. The results show that the influence of haze on images is effectively eliminated. Atmospheric correction result by the ATCOR3 and the ATCOR2 was compared, and it indicated that the ATCOR3 restore was better than ATCOR2 when the original appearance of the surface was rugged terrain..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 3, 211 (2009)
Discussion about the Spectral Resolution of the Sagnac Interference Imaging Spectrometer Caused by Offset of the Sagnac Prism
Su-ning LI, Ri-hong ZHU, Jian-xin LI, and Yan WANG
As to improve the spectral resolution of the Sagnac interference imaging spectrometer, the mathematical model of the system is analyzed. The effect of the offset of the Sagnac prism on the spectral resolution of the system is discussed, and the concrete numerical value of the prism offset is calculated. The simulation As to improve the spectral resolution of the Sagnac interference imaging spectrometer, the mathematical model of the system is analyzed. The effect of the offset of the Sagnac prism on the spectral resolution of the system is discussed, and the concrete numerical value of the prism offset is calculated. The simulation experiment is carried out by importing the simulation spectral curve and assuming that it was error free in the instrument installation. The result shows that the spectral resolution can be 2 nm by adapting the calculated offset value, which has the guiding significance for the structure design of the system..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 3, 223 (2009)
Application of CCD in Laser Heterodyne Detection System
Yu-fen MA, Guang-qi WANG, Bo CHEN, Min LI, Wan-qing WU, Chao JIANG, and Ben-li YU
In laser heterodyne detection system, the deficiencies of non-coaxial between telescope and aiming in practical applications are analyzed, and an approach by the use of spectroscope and CCD imaging technology to focus and aim is introduced. When the spot of the telescope launch beams convergent to the target is the smaIn laser heterodyne detection system, the deficiencies of non-coaxial between telescope and aiming in practical applications are analyzed, and an approach by the use of spectroscope and CCD imaging technology to focus and aim is introduced. When the spot of the telescope launch beams convergent to the target is the smallest, and the image is the clearest on CCD, the focus length is optimal; the sizes of the fields of view detected by CCD are different as the distances of target are different, but the target image and the spot location are always at the center of the field of view. So the real-time adjustment is not needed. It improves the operation and practicality greatly. Experiments are verified at last..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 3, 229 (2009)
Design for Novel Image Collection of Small Angle Laser Scattering
Cheng-lei PEI, Shi-sheng LIU, Qing-nong WEI, De-xia WU, and Wu FANG
Small angle laser scattering(SALS) is an effective measurement of the polymers spherulite radius. The conventional measurement of SALS image collection is complicated and difficult to adjust. The quality of the image is not ideal. Digital imaging technology is a good substitution, but now the main measurement is using Small angle laser scattering(SALS) is an effective measurement of the polymers spherulite radius. The conventional measurement of SALS image collection is complicated and difficult to adjust. The quality of the image is not ideal. Digital imaging technology is a good substitution, but now the main measurement is using CCD camera to collect the image directly of which the cost is high and the operation and management are not flexible. Take the advantage of CMOS imaging technology, digital CMOS camera can receive the image which is present on the ground glass by scattering light. This measurement not only reduces the cost of the hardware but also makes the operation facilitated and simplifies the SALS image collection and process..
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 3, 233 (2009)
[in Chinese]
Journal of Atmospheric and Environmental Optics
- Publication Date: Oct. 12, 2021
- Vol. 4, Issue 3, 1 (2009)
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