Dependence of thermal infrared emissive behaviors of snow cover on the surface snow type

Masahiro Hori, Teruo Aoki, Tomonori Tanikawa, Katsuyuki Kuchiki, Masashi Niwano, Satoru Yamaguchi, Sumito Matoba

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3 Citations (Scopus)

Abstract

The potential of the thermal infrared (TIR) remote sensing for discriminating surface snow types was examined by analyzing TIR radiances acquired from space over the Greenland ice sheet. The brightness temperature difference (BTD) between TIR wavelengths of 11 and 12μm was found to increase in accordance with in situ observed evolutions of surface snow type. Spatial and temporal distributions of BTD over the entire ice sheet indicated that BTD has a sensitivity of about 1.2 K for variations of the possible snow types. The observed behaviors of BTD were coincident with those predicted by a radiative transfer calculation using previous in situ measured snow emissivities, although some biases on the order of 0.1-0.3 K remain. The dependence of BTD on the surface snow type was also consistent with the behaviors of snow reflectance at the shortwave infrared (SWIR) wavelength 1.6μm, which is a measure of snow grain size, except for the case of melting wet snow. The inconsistency in the wet snow case was considered to be due to the different optical responses of the TIR and SWIR signals to wet snow, which suggested the possibility of using TIR signals to discriminate wet/dry conditions of snow cover in an old stage. As a result, it is determined that TIR remote sensing has potential not only as an approach supplementary to the SWIR method for assessing surface snow types in daytime but also as the only method for simultaneous retrieval of snow type and surface temperature in nighttime.

Original languageEnglish
Pages (from-to)33-45
Number of pages13
JournalBulletin of Glaciological Research
Volume32
Issue number1
DOIs
Publication statusPublished - Jan 1 2014

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Keywords

  • Snow and ice
  • Snow grain size
  • Spectral emissivity
  • Surface temperature
  • Thermal infrared

ASJC Scopus subject areas

  • Earth-Surface Processes

Cite this

Hori, M., Aoki, T., Tanikawa, T., Kuchiki, K., Niwano, M., Yamaguchi, S., & Matoba, S. (2014). Dependence of thermal infrared emissive behaviors of snow cover on the surface snow type. Bulletin of Glaciological Research, 32(1), 33-45. https://doi.org/10.5331/bgr.32.33