ABSTRACT
Mountainous ice sheet and snow cover play an important role in water balance in many area, and the measurement of it in large area is mainly depending on remote sensing. In order to retrieve the storage volume of snow cover in an area with remote sensing, knowing the spectral feature is prerequisite. In the present paper, the Miyaluo district in northwest of Sichuan province was selected as the study area, twenty four measurement points were laid in study area, and the ASD FieldSpec Pro III was selected as the spectral measurement instrument to collect the reflectance spectra of the snow on 21-22, January 2007. Then, the spectrum feature of the snow in the study area was analyzed. The result indicates that 1026, 1256, 1493 and 1990 nm are the characteristic absorption valleys, the snow reflectance on the surface has some relation with the snow depth, and also the snow reflectance varies with the depth in the study area.
ABSTRACT
Acid rain is a worldwide environmental problem. Serious acid rain pollution in subtropical China has constituted a potential threat to the health of the local forest. In the present paper, the changing properties of the chlorophyll concentration and spectral reflectance at the visible wavelengths for the six subtropical broad-leaved tree species leaves under simulated acid rain (SAR) treatment with different pH levels were studied. With the increasing strength of the SAR, the chlorophyll concentrations of the experimental species under pH 2.5 and pH 4.0 treatment were higher than that under pH 5.6; the spectral reflectance at the visible wavelengths for pH 2.5 and pH 4.0 were lower than that for pH 5.6 in general; while there weren't significant differences between pH 2.5 and pH 4.0. After the treatment with different levels of SAR, the differences in spectral reflectance at the visible wavelengths mainly focused around the green peak and red edge on the reflectance curve. The subtropical broad-leaved tree species studied were relatively not sensitive to acid rain stresses; some stronger acid rain may accelerate the growth of the tree species used here to some extent.
