• Spectroscopy and Spectral Analysis
  • Vol. 30, Issue 2, 448 (2010)
WU Tai-xia1、2, YAN Lei1、*, XIANG Yun1、3, ZHAO Yun-sheng4, and CHEN Wei1
Author Affiliations
  • 1[in Chinese]
  • 2Center for Remote Sensing and Mapping Science, the University of Georgia, Athens, Georgia 30602, USA
  • 3[in Chinese]
  • 4[in Chinese]
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    DOI: Cite this Article
    WU Tai-xia, YAN Lei, XIANG Yun, ZHAO Yun-sheng, CHEN Wei. The Multi-angle Polarization Spectral Character of Water and Its Applications in Water Color Remote Sensing[J]. Spectroscopy and Spectral Analysis, 2010, 30(2): 448 Copy Citation Text show less

    Abstract

    The reflectance of pure water is very low at visible and near infrared bands. Its spectral characteristics are not obvious. Water always shows dark hue in optical remote sensing images. This dark hue causes the difficulties in water remote sensing identification. There is an interesting phenomenon when the authors research the water polarization spectroscopy. The authors measured water’s polarization spectra and reflectance spectra at different view zenith angles using the ASD spectrometer. When the view zenith angle was zero (measured vertically), as the spectrum people commonly measure, there was no polarization phenomenon at the water surface, and the reflectance was low at each band. Along with the increase in view zenith angle, the DOP spectra curves increased evidently, while the reflectance curves only changed a little. When the view zenith angle was over 30 degree, the values of DOP spectrum were much larger than the reflectance spectrum values at the entire visible and near infrared bands. At some bands, the DOP value was several dozen times than its reflectance value. This phenomenon shows that the water’s brightness in DOP image is much higher than its brightness in intensity image under the same condition. This rule was verified by the PARASOL multiangle polarization satellite data. Comparing the average brightness of DOP images with the average brightness of intensity images at 490, 670 and 865 nm band, the former is higher than the latter apparently. The brighter DOP images are better for water remote sensing identification. It is the first time that the authors found this special multiangle polarization spectral character of water. It revealed the advantage of water detection using the multiangle polarization remote sensing data. This method solved the low reflectivity problem of water color remote sensing. It will greatly improve the capability of water remote sensing identification and the retrieval accuracy of water quality parameters.
    WU Tai-xia, YAN Lei, XIANG Yun, ZHAO Yun-sheng, CHEN Wei. The Multi-angle Polarization Spectral Character of Water and Its Applications in Water Color Remote Sensing[J]. Spectroscopy and Spectral Analysis, 2010, 30(2): 448
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