Spectral Reflectance Characteristics of Different Snow and Snow-Covered Land Surface Objects and Mixed Spectrum Fitting
ZHANG Jia-hua1,2,ZHOU Zheng-ming1, WANG Pei-juan1, YAO Feng-mei3*, Liming Yang4
1. Chinese Academy of Meteorological Sciences, Beijing 100081, China 2. Center for Earth Observation and Digital Earth, Chinese Academy of Sciences, Beijing 100094, China 3. College of Earth Sciences, Chinese Academy of Sciences, Beijing 100049, China 4. U.S. Geological Survey, Center for Earth Resources Observation and Science, Sioux Falls, South Dakota, 57198, USA
Spectral Reflectance Characteristics of Different Snow and Snow-Covered Land Surface Objects and Mixed Spectrum Fitting
ZHANG Jia-hua1,2,ZHOU Zheng-ming1, WANG Pei-juan1, YAO Feng-mei3*, Liming Yang4
1. Chinese Academy of Meteorological Sciences, Beijing 100081, China 2. Center for Earth Observation and Digital Earth, Chinese Academy of Sciences, Beijing 100094, China 3. College of Earth Sciences, Chinese Academy of Sciences, Beijing 100049, China 4. U.S. Geological Survey, Center for Earth Resources Observation and Science, Sioux Falls, South Dakota, 57198, USA
摘要： The field spectroradiometer was used to measure spectra of different snow and snow-covered land surface objects in Beijing area. The result showed that for a pure snow spectrum, the snow reflectance peaks appeared from visible to 800 nm band locations; there was an obvious absorption valley of snow spectrum near 1 030 nm wavelength. Compared with fresh snow, the reflection peaks of the old snow and melting snow showed different degrees of decline in the ranges of 300～1 300, 1 700～1 800 and 2 200～2 300 nm, the lowest was from the compacted snow and frozen ice. For the vegetation and snow mixed spectral characteristics, it was indicated that the spectral reflectance increased for the snow-covered land types (including pine leaf with snow and pine leaf on snow background), due to the influence of snow background in the range of 350～1 300 nm. However, the spectrum reflectance of mixed pixel remained a vegetation spectral characteristic. In the end, based on the spectrum analysis of snow, vegetation, and mixed snow/vegetation pixels, the mixed spectral fitting equations were established, and the results showed that there was good correlation between spectral curves by simulation fitting and observed ones (correlation coefficient R2=0.950 9).
关键词：Snow;Snow-covered land surface object;Spectral characteristics;Spectral fitting
Abstract：The field spectroradiometer was used to measure spectra of different snow and snow-covered land surface objects in Beijing area. The result showed that for a pure snow spectrum, the snow reflectance peaks appeared from visible to 800 nm band locations; there was an obvious absorption valley of snow spectrum near 1 030 nm wavelength. Compared with fresh snow, the reflection peaks of the old snow and melting snow showed different degrees of decline in the ranges of 300～1 300, 1 700～1 800 and 2 200～2 300 nm, the lowest was from the compacted snow and frozen ice. For the vegetation and snow mixed spectral characteristics, it was indicated that the spectral reflectance increased for the snow-covered land types (including pine leaf with snow and pine leaf on snow background), due to the influence of snow background in the range of 350～1 300 nm. However, the spectrum reflectance of mixed pixel remained a vegetation spectral characteristic. In the end, based on the spectrum analysis of snow, vegetation, and mixed snow/vegetation pixels, the mixed spectral fitting equations were established, and the results showed that there was good correlation between spectral curves by simulation fitting and observed ones (correlation coefficient R2=0.950 9).
Key words：Snow;Snow-covered land surface object;Spectral characteristics;Spectral fitting
ZHANG Jia-hua1,2,ZHOU Zheng-ming1, WANG Pei-juan1, YAO Feng-mei3*, Liming Yang4. Spectral Reflectance Characteristics of Different Snow and Snow-Covered Land Surface Objects and Mixed Spectrum Fitting[J]. 光谱学与光谱分析, 2011, 31(09): 2499-2502.
ZHANG Jia-hua1,2,ZHOU Zheng-ming1, WANG Pei-juan1, YAO Feng-mei3*, Liming Yang4. Spectral Reflectance Characteristics of Different Snow and Snow-Covered Land Surface Objects and Mixed Spectrum Fitting. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2011, 31(09): 2499-2502.
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