干旱区生态环境知识资源中心

In an attempt to utilize satellite data to obtain land surface features of Taklimakan Desert in China, in situ measurements of spectral reflectance of the land surface Is made the portable spectro radiometer in the spectral range of 400 similar to 2500 nm. The analyses of the data show following features. (1) The difference in spectral reflectance of different soils is comparatively small. (2) There is a tendency that spectral reflectance of soils increases with increases of wavelength, for example, the average reflectance of the sands in the periphery areas of Taklimakan Desert is 21 and 38 % in visible and near infrared spectra respectively. (3) It is found that reflectance of the soils decreases with increase of moisture content. The large decrease is recognized in 1450 and 1950 nm spectra, water absorption bands. This fact suggests that the monitoring of soil moisture is possible by measuring the radiance at these spectra, thus Landsat TM Bands 5 and 7 will be effective for monitoring soil moisture content.