Spectra reflectance characteristics of different snow and snow-covered land surface objects and mixed spectrum fitting

The field spectroradiometer was used to measure spectra of different snow and snow-covered land surface objects in Beijing area. For a pure snow spectrum, the snow reflectance peaks appeared from visible to 800 nm band; there was an obvious absorption valley near the 1030 nm wavelength. Comparing with fresh snow, the reflection peaks of the old snow and melting snow showed decline to varying degrees in the ranges of 300-1300 nm, 1700-1800 nm, 2200-2300 nm. For the vegetation and snow mixed spectral characteristics, it indicated that the spectral reflectance increased for the snow-covered land types, due to influence of snow background in the range of 350-1300 nm. However, the spectrum reflectance of mixed pixel remained vegetation spectral characteristics. Based on the spectrum analysis of snow, vegetation, and mixed snow/vegetation pixels, the mixed spectral fitting equations were established, the results showed that there were good correlations between spectral curves by simulation fitting and observed ones.