Journals >Journal of Atmospheric and Environmental Optics
Contents
2019
Volume: 14 Issue 5
11 Article(s)
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[in Chinese]
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 5, 1 (2019)
Experimental Investigation of Angle-of-Arrival Fluctuation of Light Propagating in Near Surface Layer Turbulent Atmosphere
MEIJie , Renmin YUAN, Xian WANG, and Xuping WU
In order to study the influence of turbulent atmosphere in the surface layer on the fluctuation of the angle of arrival(AoA) of light propagation under different meteorological conditions, an optical transmission experiment was carried out on a flat grass in the campus. A semiconductor laser was used as the light sourcIn order to study the influence of turbulent atmosphere in the surface layer on the fluctuation of the angle of arrival(AoA) of light propagation under different meteorological conditions, an optical transmission experiment was carried out on a flat grass in the campus. A semiconductor laser was used as the light source, and the light signal was received by a telescope with focal length of 1300 mm after transmitting 60 m to the receiving location, then a CCD camera was used to shoot grayscale pictures of the light spot. Ratio of the AoA fluctuations in vertical and horizontal directions was calculated based on the position of the light spot on the photo. The atmospheric turbulent refractive structure constant on the transmission path was also calculated. Simultaneously, meteorological parameters near the transmission path, such as temperature and wind speed, were measured so as to calculate the Richardson number as a stability parameter. The results showed that when the Richardson number is greater than 0.25, the ratio of vertical and horizontal AoA variances is greater than 1.0; when the Richardson number is less than 0.25, the ratio of vertical and horizontal AoA variances fluctuates around 1.0. Thus, it can be seen that atmospheric turbulence is anisotropic under stable stratification conditions and isotropic under unstable stratification conditions..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 5, 330 (2019)
Trace Cr and Cu Analysis in Aluminum Alloy by Double Pulse Laser-Induced Breakdown Spectroscopy
YANGLichao , Ruizhao YANG, Xuejiao SU, Youli YU, and Weidong ZHOU
A collinear dual pulse laser induced breakdown spectroscopy (DP-LIBS) has been used for trace element analysis in aluminum alloy. The dependence of signal intensity on the inter-pulse delay time has been carefully investigated, which gives an optimized delay time of about 8～9 μs. For the two selected analytical lines CA collinear dual pulse laser induced breakdown spectroscopy (DP-LIBS) has been used for trace element analysis in aluminum alloy. The dependence of signal intensity on the inter-pulse delay time has been carefully investigated, which gives an optimized delay time of about 8～9 μs. For the two selected analytical lines Cu I 324.75 nm and Cr I 425.43 nm, more than 10 folds enhancement of line intensities have been obtained compared to that of single-pulse laser induced breakdown spectroscopy(SP-LIBS). Calibration curves for quantitative measurement of Cu and Cr were derived using both SP-LIBS and DP-LIBS techniques. The limit of detection (LOD) of elements Cu and Cr are found to be 21.46 and 4.26 μg/g respectively with DP-LIBS, while the LOD of elements Cu and Cr are 169.5 and 94.5 μg/g with SP-LIBS..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 5, 345 (2019)
Design of Temperature Control System for Mid-Infrared Detector Used in Gas Detection
BAIYunfei , Song YE, Zhiwei LI, Hailiang SHI, Wei XIONG, Xinqiang WANG, Jiejun WANG, and Wentao ZHANG
The PbSe mid-infrared detector is the core component of the CO gas detector and its response rate varies with temperature. Accurate temperature control of the mid-infrared detector can effectively improve the stability of the system and signal-to-noise ratio. Firstly, the temperature characteristics of PbSe detector arThe PbSe mid-infrared detector is the core component of the CO gas detector and its response rate varies with temperature. Accurate temperature control of the mid-infrared detector can effectively improve the stability of the system and signal-to-noise ratio. Firstly, the temperature characteristics of PbSe detector are analyzed. According to the design index of CO detector, the high stability requirements of temperature control system are put forward. Then the working principle of thermoelectric cooler (TEC) is introduced. The temperature control scheme based on temperature and humidity control chip ADN8830 is proposed, and the corresponding input bridge circuit, TEC power amplifier circuit and PID compensation circuit are designed. Finally the experimental test system is built according to the design scheme and tested at room temperature. The test results show that, when the temperature control system is applied in the atmospheric CO concentration detection instrument, it can enter a stable state within 30 s, and the temperature fluctuation within 1 min is less than 0.02℃, which is superior to the requirement that the temperature fluctuation required for the 1 ppm accuracy index of the CO detector is not more than 0.1℃..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 5, 351 (2019)
Building of Airship Low Altitude Remote Sensing Data Management System
Lili DU, YIWeining , Dongying ZHANG, Wei FANG, and Bo SONG
Space image simulation needs a complete description and effective management of the information acquired from the unmanned airship low-altitude remote sensing measurement system. So a database system is built, which integrates hyperspectral image, high resolution image, infrared image, spectrum data, atmosphere data, eSpace image simulation needs a complete description and effective management of the information acquired from the unmanned airship low-altitude remote sensing measurement system. So a database system is built, which integrates hyperspectral image, high resolution image, infrared image, spectrum data, atmosphere data, environment data and GPS information. According to the data characteristics of the measurement system, a mobile storage model is proposed. By utilizing the superiority of binary large object (BLOB) supported by Oracle and the data partitioning technology, the model can realize the integrated management and mobile storage of the multi-source image information. The database system is developed by using Visual C++ as foreground development tool, Oracle objects for OLE (OO4O) as accessing interface and Oracle as the background database management system. Base on the adopted techniques, this system not only realizes complete description and effective organization of the data of the measurement system, but also provides a systematized and specialized information platform for space image simulation and quantitative application of multi-source remote sensing data..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 5, 359 (2019)
Methods of Ocean Subsurface Particulate Backscattering Coefficient Retrieval from CALIOP Measurements
YUSuzhen , and Dong WU
Cloud-aerosol lidar with orthogonal polarization(CALIOP) can emit 532 nm and 1064 nm laser pulses which is mainly used for the detection of clouds and aerosols in the atmosphere. The 532 nm laser pulse can be used to get backscatter signal below the sea surface due to a good penetrability to the ocean surface. Based onCloud-aerosol lidar with orthogonal polarization(CALIOP) can emit 532 nm and 1064 nm laser pulses which is mainly used for the detection of clouds and aerosols in the atmosphere. The 532 nm laser pulse can be used to get backscatter signal below the sea surface due to a good penetrability to the ocean surface. Based on the CALIOP data, the directly extracted signal and the corrected transient response signal of subsurface are studied. Firstly, the subsurface backscatters are calculated. Then the marine particulate backscattering coefficients are retrieved from two different methods, and compared to particulate backscattering coefficients from moderate-resolution imaging spectroradiometer(MODIS) products. The mean of difference value of particulate backscattering coefficients are 0.0035 and 0.0027,and the standard deviation are 0.4004 and 0.0042 respectively, which indicates that particulate backscattering coefficients derived by using transient response correction method is closer to MODIS products..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 5, 367 (2019)
Temperature Sensitivity and on-Orbit Calibration Analysis for FY-3B MERSI Shortwave Infrared Bands
Ling SUN, HUXiuqing , and Na XU
The two shortwave infrared (SWIR) bands (1.64 and 2.13 μm) of Medium Resolution Spectral Imager (MERSI) onboard FY-3B are detected by photovoltaic HgCdTe detectors. Due to the issue of radiant cooler, the SWIR band detectors operated at higher temperatures than specification, which influenced its on-orbit radiometric rThe two shortwave infrared (SWIR) bands (1.64 and 2.13 μm) of Medium Resolution Spectral Imager (MERSI) onboard FY-3B are detected by photovoltaic HgCdTe detectors. Due to the issue of radiant cooler, the SWIR band detectors operated at higher temperatures than specification, which influenced its on-orbit radiometric response. The long-term on-orbit radiometric properties of FY-3B MERSI SWIR bands at high working temperature were systematically studied. The time series of space view observation and telemetry temperature measurement were used to analyze the on-orbit temperature dependency. It revealed that there were positive correlations between the SWIR band space view and the detector temperature. Linear models were used to describe the temperature dependency and the temperature correction factors were derived. When the detector temperature changed 1℃, the space view digital number varied 0.7% and 5% for bands of 1.64 and 2.13 μm, respectively. After the temperature correction, the long-term variation of space view observations decreased significantly. The multi-site calibration method was used to obtain the on-orbit sensor radiometric response change. At the reference temperature, the total attenuations of 1.64 and 2.13 μm bands were about 6% and 11% respectively from Nov. 2011 to Dec. 2016. Through the cross comparison against Aqua moderate-resolution imaging spectroradiometer (MODIS), it revealed that when the daily calibration update model based on long-term trending analysis was applied, the radiometric differences between MERSI and MODIS were relatively stable for many years, regardless of whether the temperature effect was accounted for or not in the calibration process, which can meet the calibration expectation of 7%..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 5, 374 (2019)
Design of Driving Circuit of TDI-CCD for Ocean Observation
ZhangYuanZhen , XiaoBing Sun, and DongGen Luo
Because array CCD and linear CCD don’t meet the requirement of observing the ocean goal, the time delay integration CCD (TDI-CCD) which has high sensitivity and high signal to noise ratio is selected and driving circuit is designed. Two ports of outputs the signal during image capture. The driver circuit generates the Because array CCD and linear CCD don’t meet the requirement of observing the ocean goal, the time delay integration CCD (TDI-CCD) which has high sensitivity and high signal to noise ratio is selected and driving circuit is designed. Two ports of outputs the signal during image capture. The driver circuit generates the time sequence of the CCD and the A/D. The output analog signal of the CCD is sampled by A/D and converted to the digital signal which can be recognized by computer. FPGA is used to driving CCD and A/D, receiving the digital signal after A/D converts, and sending the imaging data to computer. The correlated double sampling (CDS) can decrease some related noise which analog output signal of the TDI-CCD has, and increase the signal to noise ratio. The code of field programmable gate array (FPGA) is simulated on the ISE14.7. The experiment results prove that the driving circuit can generate right sequence that CCD needs..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 5, 385 (2019)
Investigation of Polarization Scattering Characteristics of Single Particle Aerosols
Xu CHEN, Lei DING, Yingping WANG, Haiyang ZHENG, and Ll FANG
An experimental device for the polarization scattering of aerosol single particles is developed. The T-matrix method is used to simulate the light scattering calculation of spherical particles and long particles. The relationship between polarization intensity factor (Pf), Müller matrix elements (Z11 and Z12) withAn experimental device for the polarization scattering of aerosol single particles is developed. The T-matrix method is used to simulate the light scattering calculation of spherical particles and long particles. The relationship between polarization intensity factor (Pf), Müller matrix elements (Z11 and Z12) with particle size and shape is discussed. The results show that, with the increase of particle size, there are significant differences between spherical particles and rod-shaped particles in parameters Pf and Z12. By experimental measurement, Pf values and Z12 of different samples are obtained. The experimental results show that, using the Z12 of oleic particles as the reference, the difference ΔZ12=12 can be used as the distinguishing threshold for spherical oleic acid particles and ellipsoidal riboflavin particles and long asbestos fibers particles. The ΔZ12 of riboflavin particles ranges from 12 to 41, and when ΔZ12 reaches 59, the particles can be considered as asbestos fiber particles. However, it’s hard to distinguish cubic NaCl particles and oleic acid particles because the values Z12 of each are very similar. Preliminary experiments show that Müller matrix element Z12 can be used to identify long particles, which can help to design morphology measurement instrument with polarization method..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 5, 321 (2019)
Comparison of LTE and non-LTE Model for Limb Infrared Radiation Simulation of Middle and Upper Atmosphere
Dong LIU, Congming DAI, and Heli WEI
The simulation algorithms for limb infrared radiation in the middle and upper atmosphere are investigated using strategic high-altitude radiance code (SHARC) and combined atmospheric radiative transfer (CART) model. The results confirm the availability of CART limb model preliminarily. The comparison shows that local tThe simulation algorithms for limb infrared radiation in the middle and upper atmosphere are investigated using strategic high-altitude radiance code (SHARC) and combined atmospheric radiative transfer (CART) model. The results confirm the availability of CART limb model preliminarily. The comparison shows that local thermodynamics equilibrium(LTE) model is effective under at least 45 km tangent altitude for the main limb infrared radiance simulation, while non-local thermodynamics equilibrium(non-LTE) model should be applied starting from different altitudes for the different infrared bands and atmospheric conditions. For 15 μm band, LTE model can be effective under at least 80 km tangent altitude; but for 4.3 μm band and 9.6 μm band, non-LTE model should be applied about above the stratosphere..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 5, 337 (2019)
Integrated Experimental Prototype of Spectropolarimeter Based on PSIM
Jingsong HU, Zhiping SONG, Zhiwei LI, Minghui ZHANG, and Ziyun ZHANG
In order to apply the polarization spectral intensity modulation (PSIM) technology to the fields of outdoor polarization remote sensing, an integrated PSIM spectropolarimeter experimental prototype is designed based on the laboratory principle model. First, a modulator consisting of a Glan-Taylor prism and two quartz cIn order to apply the polarization spectral intensity modulation (PSIM) technology to the fields of outdoor polarization remote sensing, an integrated PSIM spectropolarimeter experimental prototype is designed based on the laboratory principle model. First, a modulator consisting of a Glan-Taylor prism and two quartz crystal retarders is integrated into a module. Then the module is mounted on the head of the grating spectrometer to realize integrated hardware design of the PSIM spectropolarimeter. Based on interactive data language (IDL), the functions of file accessing , data processing and result displaying are integrated into one unified interface to realize an integrated software design of the PSIM spectropolarimeter. Finally, the measurement capability of the experimental prototype is verified by measuring the whole Stokes vector element spectrum of horizontal and vertical linear polarized light, and the polarization calibration of the experimental prototype is accomplished by using polarization calibration system. Experimental data processing results show that experimental prototype can synchronously achieve the whole Stokes vector element spectrum of the testing light, and the maximum error between the measured results of the experimental prototype and the theoretical output results is about 0.003 for the degree value of polarization in full spectrum of the light from the polarization calibration box. It is indicated that the design goal of integrated experimental prototype is realized..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 5, 393 (2019)
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