Abstract. Angular distributions of spectral re � ectance for four common arctic surfaces: snow-covered sea ice, melt-season sea ice, snow-covered tundra, and tundra shortly after snowmelt were measured using an aircraft-based, high angular resolution (1°) multispectral radiometer. Results indicate b...
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| Format: | Text |
| Language: | English |
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1999
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.385.5287 http://modis-atmos.gsfc.nasa.gov/_docs/Arnold_et_al._(2002).pdf |
| Summary: | Abstract. Angular distributions of spectral re � ectance for four common arctic surfaces: snow-covered sea ice, melt-season sea ice, snow-covered tundra, and tundra shortly after snowmelt were measured using an aircraft-based, high angular resolution (1°) multispectral radiometer. Results indicate bidirectional re � ectance is higher for snow-covered sea ice than melt-season sea ice at all wavelengths between 0.47 and 2.3 mm, with the diVerence increasing with wavelength. Bidirectional re � ectance of snow-covered tundra is higher than for snow-free tundra for measurements less than 1.64 mm, with the diVerence decreasing with wavelength. Bidirectional re � ectance patterns of all measured surfaces show signi-� cant re � ectance maxima in the forward scattering direction of the principal plane with identi � able specular re � ection for the melt-season sea ice and snow-free tundra cases. The snow-free tundra had the most signi � cant backscatter (similar to other vegetative bidirectional re � ectance patterns such as for Cerrado in Brazil), and the melt-season sea ice the least. For sea ice, bidirectional re � ectance changes due to snowmelt were more signi � cant than diVerences among the diVerent types of melt-season sea ice. The spectral-hemispherical (plane) albedo of each measured arctic surface was also computed. Comparing measured nadir re � ectance to albedo for sea ice and snow-covered tundra shows nadir re � ectance 5–40 % smaller, with the largest diVerence at wavelengths beyond 1 mm. For snow-free tundra, nadir re � ectance is 30–50 % smaller than the plane albedo. 1. |
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