Journals >Journal of Atmospheric and Environmental Optics
Contents
2020
Volume: 15 Issue 2
10 Article(s)
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[in Chinese]
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 15, Issue 2, 1 (2020)
Progress of Retrieval of Atmospheric Temperature and Water Vapor Profiles based on Infrared Spectra
Huijie ZHAO, Zhiyuan MI, Xiaohang MA, and Guorui JIA
Atmospheric temperature and humidity profile is the key and basic meteorological parameter in the analysis of atmospheric thermal state, the study of atmospheric development and changes, severe weather warning, and numerical weather prediction. Retrieval algorithm of atmospheric temperature and humidity based on infrarAtmospheric temperature and humidity profile is the key and basic meteorological parameter in the analysis of atmospheric thermal state, the study of atmospheric development and changes, severe weather warning, and numerical weather prediction. Retrieval algorithm of atmospheric temperature and humidity based on infrared spectra has been developed since 1960s, and can be divided into ground-based infrared retrieval algorithm and satellite-based infrared retrieval algorithm according to different observation positions. Basic types of retrieval algorithms of atmospheric temperature and humidity based on infrared spectra are summarized. The development of ground-based and satellite-based infrared detection methods for atmospheric temperature and humidity profile retrieval is introduced. Meanwhile, the retrieval method of atmospheric states combining ground-based with satellite-based infrared sounder is analyzed. Finally, the applications and development trend of atmospheric temperature and humidity profile retrieval method based on infrared spectra are briefly discussed..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 15, Issue 2, 81 (2020)
Implementation of Solar Speckle Image Reconstruction Based on GPU
Jingwei XUAN, Changhui RAO, Libo ZHONG, and Yu TIAN
In ground-based solar observation, when the light passes through atmosphere, it will be affected by atmospheric turbulence which will cause translation, distortion and blurring of the received image. In order to eliminate or reduce the effects of atmospheric turbulence, post-image processing technology was used to obtaIn ground-based solar observation, when the light passes through atmosphere, it will be affected by atmospheric turbulence which will cause translation, distortion and blurring of the received image. In order to eliminate or reduce the effects of atmospheric turbulence, post-image processing technology was used to obtain high-resolution solar images. High-resolution image can be obtained by post-facto reconstruction algorithm based on the speckle interferometry and speckle masking. However, due to its complex calculation, the algorithm can not meet the requirement of real-time detection. On the basis of the principle of the algorithm, solar speckle image reconstruction algorithm has been parallelized by using CUDA parallel computing architecture in this research. The experimental results show that a 2304 pixel×1984 pixel image of TiO channel can be reconstructed within 70 s under GPU environment. Compared with the program running on CPU, the speed-up radio can up to 7..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 15, Issue 2, 90 (2020)
Simulation ofWavefront Phase Reconstruction by Plenoptic Sensor
Yao LIU, Chunhong QIAO, Xiaoxing FENG, Jinghui ZHANG, Haitao WANG, and Chengyu FAN
The ability of plenoptic sensor to reconstruct wavefront phase was studied by means of software simulation, where FFT algorithm was used to simulate the wave propagation and diffraction effects, Zernike polynomial was used to simulate the aberration, and the wavefront phase was reconstructed according to the theory of The ability of plenoptic sensor to reconstruct wavefront phase was studied by means of software simulation, where FFT algorithm was used to simulate the wave propagation and diffraction effects, Zernike polynomial was used to simulate the aberration, and the wavefront phase was reconstructed according to the theory of plenoptic mapping and inverse plenoptic mapping. The wavefront phase reconstruction of the first 22 single-order aberrations was studied, and the reconstruction results of the primary aberration and the secondary aberration were compared and analyzed. In addition, multiple sets of simulation experiments were conducted for the wavefront reconstruction of the complex aberrations, and the reconstruction errors of the lower-order complex aberrations and higher-order complex aberrations are also compared. The results show that the plenoptic sensor can reconstruct the wavefront phase regardless of the single-order aberration or the complex aberrations, and the phase reconstruction effect for the lower-order aberration is better than that of the higher-order aberration..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 15, Issue 2, 101 (2020)
Effect of Sample Temperature on Radiation Characteristics of Laser-Induced Cu Plasma
Li WANG, Yu ZHOU, Hao GONG, Yuanxia FU, and Li XU
In order to study the effect of sample temperature on the characteristic parameters of laser-induced copper plasma, Cu sample on heating stage was excited by a single pulse laser to form plasma, and the corresponding plasma emission spectra of brass were obtained by changing the sample temperature. The intensity changeIn order to study the effect of sample temperature on the characteristic parameters of laser-induced copper plasma, Cu sample on heating stage was excited by a single pulse laser to form plasma, and the corresponding plasma emission spectra of brass were obtained by changing the sample temperature. The intensity change of the characteristic spectral line corresponding to the change of sample temperature was analyzed, and the evolution rule of electron temperature and electron density with time at different sample temperatures are obtained by using Boltzmann equation and Stark broadening under the assumption of local thermodynamic equilibrium (LTE). At the same time, the cause of the radiation enhancement of laser-induced metal plasma was also discussed. The results showed that, given the same delay time, the higher the sample temperature is, the stronger the spectral intensity is, and the higher the electron temperature and electron density are. It is indicated that the resulting spectral intensity can be increased by increasing the sample temperature appropriately..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 15, Issue 2, 110 (2020)
Sophisticated Vegetation Classification Based on Multi-Dimensional Features of Hyperspectral Image
Yuhong MIAO, Min YANG, and Guojun WU
At present, there are three major challenges in the sophisticated vegetation classification using hyperspectral image. The first is that the accuracy of classification obtained simply by using spectral information is low. The second is that the presence of noise in the spectral data affects the final classification resAt present, there are three major challenges in the sophisticated vegetation classification using hyperspectral image. The first is that the accuracy of classification obtained simply by using spectral information is low. The second is that the presence of noise in the spectral data affects the final classification results, and the third is the lack of classification methods designed for specific application scenarios. To this end, a method for sophisticated vegetation classification based on multi-dimensional features of hyperspectral images is proposed. In this method, hyperspectral image data are analyzed and utilized firstly through three aspects of spectral data dimension reduction, texture feature extraction and vegetation index selection. And then, based on the distribution of ground vegetation obtained from previous field surveys, training samples are selected and Support Vector Machine (SVM) supervised classification is performed, which results in the sophisticated classification of ground vegetation at last. To verify the classification results, the overall accuracy can reach 99.6%. The result shows that vegetation classification based on multi-dimensional features of hyperspectral image can effectively reduce data noise and improve information utilization rate, and can provide more reliable data support for vegetation ecological monitoring work..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 15, Issue 2, 117 (2020)
Quantitative Comparison of Normalized Difference Water Index of GF-1 and Landsat8 images in Karst Region
Siyuan CHEN, Dandan LU, and Shuiting Wu
Youjiang River Valley in Tianyang County of Baise City, Guangxi, China, is taken as the research sample area, and the normalized differencewater index (NDWI) of remote sensing images of GF-1 and Landsat8 for this Karst area is quantitatively analyzed to provide important scientific support for the study of Karst water Youjiang River Valley in Tianyang County of Baise City, Guangxi, China, is taken as the research sample area, and the normalized differencewater index (NDWI) of remote sensing images of GF-1 and Landsat8 for this Karst area is quantitatively analyzed to provide important scientific support for the study of Karst water resources. Specifically, the valley basins and Karst rocky mountains in the Karst valley are selected as the study areas. Firstly, the normalized water index (NDWI) of the two types of remote sensing images are calculated respectively. Then combined with visual interpretation, the accuracy of water body identification and normalized water body index of the two types of images are compared. At last,the quantitative relationship between normalized water index of images is quantitatively analyzed and compared. The results show that the high-resolution images of GF-1 are superior to those of Landsat8 in valley and mountain areas, especially for the recognition of mixed directional elements. As for the threshold of water identification, the mixed pixels of high-resolution images are mostly between 0.6 and 0.8, and the NDWI values of water bodies are mostly around 1.0. The mixed pixels of Landsat8 are in the range of －0.2～0, and the NDWI value of water body is more than 0. In addition, the NDWI values of the two images have a certain linear relationship, but the quantitative regression results are not so satisfactory. It seems that both GF-1 and Landsat8 are qualified for identifying mountain topography and valley zones in Karst area, however, the estimafion accuracy and effect of GF-1 are better than Landsat8..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 15, Issue 2, 125 (2020)
Retrieve of Spatial and Temporal Distribution of Suspended Sediment in Bohai Bay Based on GF-1 Remote Sensing Satellite
Xinli CAI
Suspended sediment is one of the important parameters to evaluate the quality of Case II Waters. As the suspended sediment in coastal waters has a certain adsorption effect on heavy metals and nutrients, its distribution characteristics can reflect transferring and circling of pollutants to some extent. Therefore, the Suspended sediment is one of the important parameters to evaluate the quality of Case II Waters. As the suspended sediment in coastal waters has a certain adsorption effect on heavy metals and nutrients, its distribution characteristics can reflect transferring and circling of pollutants to some extent. Therefore, the study of suspended sediment is of great significance to the construction and environmental protection of Bohai Bay, China. In order to explore the variations of sediment index and distribution of suspended sediment in Bohai Bay, the suspended sediment index of the Bohai Bay is retrieved by band combination from the multi-spectral satellite image of GF-1, and the suspended sediment indexes of the nine months in 2019 are obtained. It is found that the suspended sediment in Bohai Bay is greatly influenced by monsoon in winter, and in spring and summer, the suspended sediment of high concentration shrinks towards nearshore. Besides, the distribution pattern of suspended sediment in fall has a trend of transition to that of winter. The study provides an important scientific basis and reference for the ecological environment protection and industrial development in Bohai Bay..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 15, Issue 2, 134 (2020)
Evolution and Prediction of Thermal Environment Pattern in Nanjing Based on CA-Markov Model
Jiqiang GUO, and Jie PAN
Based on Landsat5 TM and Landsat8 OLI/TIRS data, the land surface temperature of Nanjing city is retrieved by radiative transfer equation, and the thermal landscape pattern evolution is analyzed by landscape pattern indices. Then the thermal environment change of Nanjing in 2024 is predicted by CA-Markov model. The resBased on Landsat5 TM and Landsat8 OLI/TIRS data, the land surface temperature of Nanjing city is retrieved by radiative transfer equation, and the thermal landscape pattern evolution is analyzed by landscape pattern indices. Then the thermal environment change of Nanjing in 2024 is predicted by CA-Markov model. The results show that, from 2000 to 2017, the area of high temperature zone in Nanjing increased by 456.55 km2 and 149.75 %, and the area of mid-temperature zone, low and sub-low temperature zone decreased continuously. On the patch-class level, the dominance of high temperature patch in thermal landscape pattern was rising rapidly. From 2000 to 2010, the fragmentation and complexity of the high temperature patch decreased, which is contrary to that from 2010 to 2017. On the landscape level, the fragmentation degree of thermal landscape pattern in Nanjing decreased, the area of various patches tended to be uniform, and the degree of aggregation among patches increased. It is shown that the simulation result of thermal environment of Nanjing in 2017 based on CA-Markov model has a high simulation accuracy, with the average error of each heat island type less than 6% and the Kappa index of the model of 78.36%. The prediction results of thermal environment of Nanjing in 2024 show that the area of high temperature and sub-high temperature zone will increase by 94.96 km2 and 126.91 km2 respectively, and the area of mid-temperature zone, low and sub-low temperature zone will continue to decrease..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 15, Issue 2, 143 (2020)
Design of CCD High Speed Wire diameter Measurement Simulation System
Haibin WU, Mengnan LI, Xinbing CHEN, Dongxu HOU, and Tao HE
A high precision wire diameter measurement simulation system is designed, which is composed of parallel light source, double telecentric lens, CCD camera and object to be tested. Considering that this experimental system is designed to simulate the photography and measurement of high-speed wire, the radial velocity of A high precision wire diameter measurement simulation system is designed, which is composed of parallel light source, double telecentric lens, CCD camera and object to be tested. Considering that this experimental system is designed to simulate the photography and measurement of high-speed wire, the radial velocity of wire rod can be as high as 100 m/s in the rolling process, and there are signs of transverse runout. Therefore, in the optical design, a telecentric lens with a fixed magnification rate is used to keep the image size on photosensitive surface unchanged when the distance is changed. Moreover, the maximum exposure time of the selected plane array CCD can reach 1μs, thus a high-definition image reflecting the size of the measured object can be obtained in real-time. The experimental results show that the diameter accuracy of the workpiece measured by the simulation system can reach 20 μm, which can meet the needs of production..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 15, Issue 2, 154 (2020)
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