Abstract ▼ AI-Helper

The infrared radiance measured from satellites is affected by photons emitted from the surface and atmosphere. Thus, the brightness temperature calculated from radiative transfer model can be differ by 3K if the emissivity contains 3% error. This study measured the emissivity spectra of 7 major rock...

The infrared radiance measured from satellites is affected by photons emitted from the surface and atmosphere. Thus, the brightness temperature calculated from radiative transfer model can be differ by 3K if the emissivity contains 3% error. This study measured the emissivity spectra of 7 major rock-forming minerals using a FT-IR spectrometer in the spectral region of 650~1400 cm-1. We compared emissivity spectra measured in this study with spectra provided by Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Arizona State University (ASU). The emissivity spectral features such as Reststrahlen Band (RB) and Christiansen Feature (CF) locations were compared. Results showed that both CF and RB locations of emissivity spectra measured in this study were similar to those from ASTER and ASU. In the case of quartz, the RB was occurred in the region of 700∼850 cm-1 and 1050∼1250 cm-1. The spectral position (1159 cm-1) of emissivity peak was exactly consistent with the location of ASTER and ASU. For plagioclase, the spectral location of CF was shifted toward larger wavenumber and the emissivity value was increased in the region of 870~1200 cm-1 as Ca percentage increased. The spectral position of CF for anorthite and bytownite was occurred at 1245.79 cm-1, and that for albite was occurred at 1283.79 cm-1. In the case of phyllosilicate minerals, RB of illite was occurred in the region of 700~820 cm-1 and 1050~1250 cm-1, and that of muscovite was occurred in the region of 900~1250 cm-1. We also confirmed that emissivity feature of sandstone includes both emissivity features of quartz and calcite. However there were differences in the magnitude of emissivity and locations of RB and CF. These were due to the differences in measurement methods, and differences in particle size and temperature of samples.

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