Journals >Journal of Atmospheric and Environmental Optics
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2019
Volume: 14 Issue 6
10 Article(s)
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[in Chinese]
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 6, 1 (2019)
Transmission Analysis of Off-Axis High Order Bessel-Gaussian Vortex Beam
Shenzhe LIU, Zhenjiang SONG, Xiujun HUANG, Dele SHI, Mingshun JIANG, SUIQingmei , and Dejun FENG
The off-axis transmission of high order Bessel-Gaussian vortex beam produced by spiral phase plate (SPP) and axicon is studied, which can provide reference for the off-axis high order Bessel-Gaussian beams’ formation, intensity distribution control, spot location and other practical applications. On the basis of the thThe off-axis transmission of high order Bessel-Gaussian vortex beam produced by spiral phase plate (SPP) and axicon is studied, which can provide reference for the off-axis high order Bessel-Gaussian beams’ formation, intensity distribution control, spot location and other practical applications. On the basis of the theory of diffraction, the transmission of the higher order off-axis Bessel-Gaussian beams is simulated and analyzed by using the triple fast Fourier transform (T-FFT) algorithm. The effects of dislocation parameters, topological charge numbers and transmission distances of SPP and the axicon on the beams are considered during the simulation. The analysis shows that the off-axis higher-order Bessel-Gaussian beams have an uneven light intensity distribution. Due to the shift of the axicon, the beams will be shifted as a whole and the uneven distribution of light intensity at different distances is different. Different topological charge only affects the light spot expansion. Various combinations of the off-axis parametric values for SPP and the axicon will generate different light intensity distributions and even dark core’s shifts..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 6, 401 (2019)
Temporal Characteristics of Aerosol Optical Depth Based on Cluster Analysis Method
Zhuang LIU, Chenlie SHI, Meng ZHANG, Zhiyuan GAO, ZHUXinming , and Xuhong WANG
Using the K-means cluster analysis method, the times series of aerosol optical depth (AOD) over central and eastern China from March 2008 to February 2018 were analyzed based on the data of moderate resolution imaging spectroradiometer (MODIS) MOD08M3. The results show that: 1) The characteristics of time series of AODUsing the K-means cluster analysis method, the times series of aerosol optical depth (AOD) over central and eastern China from March 2008 to February 2018 were analyzed based on the data of moderate resolution imaging spectroradiometer (MODIS) MOD08M3. The results show that: 1) The characteristics of time series of AOD were analyzed from the pixel scale, which avoided the problem of rules mixing and leaded to the acquisition of accurate variation rules and fluctuation scales. 2) Four regional results were obtained on the inter-annual change scale, and the inter-annual variation of AOD was mainly influenced by the factor of population distribution. 3) There are 9 types of change zones on the inter-seasonal fluctuation scale, namely, North China plain region, Middle-Lower Yangtze River region, Plateau Mountain region, Yunnan-Guizhou region, Lanzhou-Yinchuan-Alxa region, Sichuan Basin region, Guanzhong-Shaannan region, Guangdong-Guangxi-Southern Hunan-Southern Jiangxi region, and the Southeast Coastal region. And the dominant influencing factors of seasonal fluctuations of AOD in the areas have been obtained based on the geographical location of some changes in the sub-regions. These results are helpful to study the precise changes of the AOD time series and the climatic environment in the central and eastern regions..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 6, 411 (2019)
Design and Implementation of Stepping Motor Control System Based on BM3803
Quan XU, Shuhua HUANG, Fuqi SI, Chunhui HAN, Shen ZHANG, LUYuelin , and Wenqing LIU
Aiming at the realization of the sun-calibrated optical path switching component of the space-borne differential optical absorption spectrometer, a stepping motor control system based on BM3803 is proposed. The switching of the optical path can be realized by rotating the concave mirror with torsion spring driven by thAiming at the realization of the sun-calibrated optical path switching component of the space-borne differential optical absorption spectrometer, a stepping motor control system based on BM3803 is proposed. The switching of the optical path can be realized by rotating the concave mirror with torsion spring driven by the stepping motor. Firstly, the open-loop control system of stepping motor based on domestic aerospace chip BM3803FMGRH and special drive chip LMD18200 is designed. Then the control circuit based on BM3803FMGRH and the drive circuit of LMD18200 are constructed, and the control program of stepper motor is programmed. When the stepping motor rotates 89 steps, the torsion spring rotates at an angle of 80.1°, the micro switch is turned on, and the optical path is switched successfully. It provides a reference for the design of the subsequent space-borne differential absorption spectrometer..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 6, 463 (2019)
[in Chinese]
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 6, 474 (2019)
[in Chinese]
[in Chinese]
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 6, 479 (2019)
Analysis of Meteorological Elements and Forecast Method of Haze Day in Hefei, China
Chunxuan WEI, He HUANG, Zhenfang ZHAI, and Ping ZHANG
Based on available observation data of Hefei Meteorological Station from 1952 to 2016 and the daily ground and altitude observation data from 2004 to 2016, the characteristics of haze day and related meteorological elements are analyzed. Then combining with the air pollution data of Hefei from 2004 to 2016, the predictBased on available observation data of Hefei Meteorological Station from 1952 to 2016 and the daily ground and altitude observation data from 2004 to 2016, the characteristics of haze day and related meteorological elements are analyzed. Then combining with the air pollution data of Hefei from 2004 to 2016, the prediction equations of haze day and the visibility in haze day are obtained preliminarily. Finally, the forecast results are verified by using the meteorological and air quality data of 2017. The results show that haze in Hefei is dominated by slight haze and mild haze, and the haze days distribute unevenly month by month, with the most haze days in January and December. The growth and elimination of haze have diurnal changes. Haze occurrs mainly at 11 to 20 o’clock every day. The favorable meteorological conditions for haze day are as follows: wind speed is less than 3 m/s, the leading wind direction is easterly or southerly, with negative pressure, positive temperature and relative humidity of 50～70%. Low visibility haze requires high relative humidity and negative pressure. It is shown that the prediction equations have high accuracy, which can provide some reference for haze forecasting in Hefei..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 6, 419 (2019)
Simulation of Spatial Concentration Distribution of Urban Road PM10 Based on SVR-LUR Model
Wenjun CHEN, and Hongdi HE
The traditional land use regression(LUR) model does not consider the nonlinear complex relationship between impact factors and atmospheric pollutants. Taking PM10 as an example, Support Vector Machine Regression (SVR) has been used to improve the land use regression model modeling method to construct SVR-LUR model, andThe traditional land use regression(LUR) model does not consider the nonlinear complex relationship between impact factors and atmospheric pollutants. Taking PM10 as an example, Support Vector Machine Regression (SVR) has been used to improve the land use regression model modeling method to construct SVR-LUR model, and then the spatial distribution of PM10 around Nanpu Bridge in Shanghai, China is simulatedbased on the model. The results show that: 1) There is a high correlation between the PM10 concentration and the empty area in the 100 m buffer zone, the construction area, the empty area and the river area in the 150 m buffer zone, the green area and the river area in the 200 m buffer zone, as well as the humidity, traffic flow and background concentration. 2) the SVR-LUR model can better predict the spatial distribution of PM10 concentration in the study area. Compared with LUR model, SVR-LUR model has higher prediction accuracy. Compared with LUR model, the mean absolute error (MAE) and root mean squares error (RMSE) oftest set of SVR-LUR model reduces by are22.92%, 33.51% less than those of LUR model, MAE and RMSE respectively, and whilethe index of agreement (IA) value increases by 13.20%. Compared with the prediction results of single gradient spatial distribution obtained by ordinary Kriging interpolation model, SVR-LUR model can more effectively reveal the spatial differences in a small range. 3) The spatial distribution of PM10 concentration in the study area shows a general pattern of high concentration in the west and low in the east. The concentration is higher in the areas with dense buildings and road network, but relatively lower in the areas near the river and open space. The simulation results are consistent with the actual situation..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 6, 431 (2019)
Spatial-Temporal Distribution Characteristics of CO2 over Globe and East Asia by AIRS Satellite
Shaohui ZHANG, Bing XIE, Hua ZHANG, and Xixun Zhou
Based on atmospheric infrared sounder (AIRS ) satellite data from December 2002 to November 2016, the spatial-temporal characteristics of CO2 concentration in different seasons over globe and East Asia (70～140°E, 10～55°N) were analyzed and compared with the surface observation data. The results show that: 1) Based on atmospheric infrared sounder (AIRS ) satellite data from December 2002 to November 2016, the spatial-temporal characteristics of CO2 concentration in different seasons over globe and East Asia (70～140°E, 10～55°N) were analyzed and compared with the surface observation data. The results show that: 1) the correlation coefficient between the CO2 data of AIRS and the surface observation data is above 0.9, and the relative error of annual mean value is within 1%. 2) The global annual mean CO2 concentration increased from 357.16 ml/m3 in 2003 to 401.24 ml/m3 in 2016, with an average annual growth date of about 2.01 ml/m3. While it increased from 357.13 ml/m3 to 402.22 ml/m3 during the same period over East Asia, with an average annual growth rate of about 2.08 ml/m3 which is a bit higher than that of globe. Over most of the Northern Hemisphere, the CO2 concentration growth rate during 2010～2016 is lower than that of during 2003～2009. In particular, mean CO2 concentration increased markedly over central Siberia and Greenland. 3) The distributions of CO2 concentrations had obviously regional features. The regions with high CO2 concentration were over middle and high latitudes in the Northern Hemisphere, whereas the regions wtih low CO2 concentration were mainly located over Tibet Plateau. In the Southern Hemisphere, the regions with high concentration was located in the middle latitudes, while the region with low concentration was located in the low latitudes of Atlantic (0～20°S, 50°W～5°E). In the middle and lower troposphere (4～6 km), the seasonal variation characteristics of CO2 concentration retrieved by AIRS was highly reliable. Especially in winter, over most of the Northern Hemisphere, CO2 concentration decreased first and then increased with time. 4) In East Asia, the high CO2 concentration was located in the Northern China with zonal distribution..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 6, 442 (2019)
Building Height Extraction Based on GF-2 Satellite Remote Sensing Data
Qiang ZHAO, Zhi YANG, Hongchao SU, and Shizhi YANG
Building height information extraction is one of the hot issues in urban spatial information acquisition by high-resolution satellite remote sensing. An object-oriented building height retrieval method based on the rules of the information is proposed in this work in order to extract building height information accuratBuilding height information extraction is one of the hot issues in urban spatial information acquisition by high-resolution satellite remote sensing. An object-oriented building height retrieval method based on the rules of the information is proposed in this work in order to extract building height information accurately. Firstly, the building shadow extraction algorithm based on rule information was established according to the building shadow geometry, texture and spectral characteristics, and building shadow information was extracted. Then the length of the shadow was calculated by computing the average value of pixels, and the building height was inverted by using the spatial model of satellite, the sun, the building and its shadow. Two building height retrieval experiments was carried out based on GF-2 satellite remote sensing data of the two experimental area of Yangzhou (Jiajia garden and Shanwan community). Through the actual height measurement of 105 buildings, the retrieval results are verified and the overall accuracy is 96.5%. It shows that the method has high precision in the aspect of city building height information extraction..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 6, 455 (2019)
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