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Linear polarization characteristics for terrain identification at millimeter wave band

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Chinese Optics Letters 2014年第10期12卷 46-49页

作者：逯暄肖泽龙许建中 School of Electronic and Optical Engineering Nanjing University of Science and Technology

We experimentally research linear polarization characteristics of various terrains at millimeter wave band for image interpretation. We measure and discuss the polarization phenomena, and consider as well the incident angle which also affects terrain radiometric temperature. An economic single-channel radiometer is used in measurements, and changes to the linear polarization are produced by manually rotating its waveguide. We demonstrate that the characteristic in polarization is a decisive advantage of terrain identification in ways beyond that which can be achieved using an intensity radiometer alone.

关键词： Landforms Polarization radiometers

Transfer method to calibrate the normalized radiance for a CE318 Sun/sky radiometer

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Chinese Optics Letters 2015年第4期13卷 16-20页

作者：李凯涛李正强李东辉李伟 Luc Blarel Philippe Goloub Torres Benjamin 许华谢一凇侯伟真李莉陈兴峰 State Environmental Protection Key Laboratory of Satellite Remote Sensing Institute of Remote Sensing and Digital EarthChinese Academy of Sciences University of Chinese Academy of Sciences Hefei University of Technology University of Lille 1

A transfer method is introduced to derive the normalized radiance for CE318 Sun/sky radiometer using viewing solid angles and extraterrestrial calibration constants. The new transfer method has a good consistency at different parts of the sky scanning. Error analysis suggests that the uncertainty of the transferred method is about 2.0%-2.4%. The normalized radiances are used as input of the aerosol inversion to test the performance of the new transfer method. The residuals of the inversion （e.g., difference between fitted and measured radiance） are chosen as the index of the radiance calibration accuracy. Analyses of one year＇s measurements in Beijing suggest an average sky residual of 3.3~ for almucantar scanning （while 3.7% for the AERONET method）, which suggest a better accuracy of the transfer method when used in aerosol retrieval.

关键词： Aerosols radiometers Uncertainty analysis

Measurement of water-leaving radiance on smooth water surfaces at different viewing angles using high-resolution spectroradiometer

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Chinese Optics Letters 2012年第6期10卷 77-80页

作者：吕云峰孙仲秋赵云升 College of Urban and Environmental Sciences Northeast Normal University College of Urban and Environmental Sciences Changchun Normal University

This letter describes a method for calculating water-leaving radiance on smooth surfaces at different angles based on Fresnel law and the polarized measurements using an ASD FS3 spectroradiometer. The spectroradiometer is mounted on a goniometer so that it views the water surface from a height of several decimeters at different viewing angles through a linear polarizing filter. The incident angles equal the viewing angles. The water-leaving radiance spectra acquired by other methods are compared with the polarized measurements from the smooth water surface, and the radiance spectra obtained by the proposed method are found to be consistent with the results of the reference methods. The current study provides another effective technique for measuring water-surface reflectance via remote sensing. Moreover, the method does not avoid the sun glint during the detection of water-leaving radiance in cases where the viewing geometric position is clear.

关键词： radiometers Remote sensing

Satellite retrieval of inherent optical properties in the turbid waters of the Yellow Sea and the East China Sea

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Chinese Optics Letters 2010年第8期8卷 721-725页

作者：崔廷伟张杰唐军武马毅青松 First Institute of Oceanography State Oceanic Administration National Satellite Ocean Application Service State Oceanic Administration

In situ-satellite match-ups of radiometric data are established in the turbid waters of the Yellow Sea and the East China Sea. Inherent optical properties （IOPs） are retrieved by match-up radiometric data and multi-band quasi-analytical algorithm （QAA）. By comparing in situ spectra-retrieved IOPs with the satellite ones of moderate resolution imaging spectroradiometer （MODIS） and medium resolution imaging spectrometer （MERIS）, the accuracy of satellite-derived IOPs is quantified. The median of the absolute percentage difference is found to be approximately 20% for the total absorption coefficient at（λ） at green and blue-green bands, and 30% for particulate material backscattering coefficient bbpλ throughout the visible bands. The spatial pattern and temporal variability of IOPs along the eastern coast of China are clarified based on satellite images and the QAA model.

关键词： Backscattering Coastal zones radiometers Radiometry Satellite imagery Spectrometers