Measuring surface water in soil with light reflectance

摘要

The light absorbed by water in soil and plants is readily determined using hyperspectral full-range imagery and field spectrometers. The full absorption of light can be accounted for by fitting the shape of water absorptions at the same time as other diagnostic bands using multiple Gaussian functions. This research is particularly important in soils due to the loss of mineral band depth with the spread of the fundamental water just beyond the SWIR. The relationship of the albedo lost to band depth, for the same mineral media, is nonlinear. By including water and mineral absorptions in the same fitting, the accuracy of the mineral abundance estimates are shown substantially improved. In addition, measurements of absorption change within the soil surface are so sensitive to water content that these bands as indexes and absorption fitting are excellent predictors of the amount of organic matter. Spectral model is shown for determining water content based water indexes and the fitted SWIR band as a good predictors of soil biological crust, such as lichen and cyanobacteria, in hyperarid soils of the Mojave Desert.