| Desert dust and its associated problems are critical to many civilian and military activities. A method to remotely interpret the surface characteristics of desert landforms would be useful in predicting dust generation potential and trafficability. Playas are representative landforms; characteristically broad, flat, sparsely vegetated, and often extensive. This terrain is strategically and tactically significant for such military operations as aircraft landing sites, cross-country movement, cover and concealment, and registration of inertial navigation systems. Some playa surfaces are soft, moist, high in silt or salt content, with low bearing strength. Other surfaces are hard, dry, and clay-rich; adequate for most vehicle and aircraft loads.; The purpose of this investigation was to develop a method to identify playa surface characteristics using remote-image techniques. Fifteen Mojave Desert playas were classified according to surface configuration, field spectral reflectance and dust concentration measurements, and physical and chemical soil properties.; Results include moisture contents of 4 to 20 percent; electrical conductivity values of 1 to 85 mmho/cm; carbonate contents of 1 to 11 percent; clay mineral assemblages of montmorillonite, illite, kaolinite, and minor chlorite; dust concentrations of 1.1 to 4.0 g/m3; significant variation in particle-size distribution; and spectral reflectance values within the 0.3- to 2.5-micron range.; Results indicate that the hard, dry playa surfaces are: (1) higher in clay content (predominately montmorillonite), (2) lower in moisture content, (3) less saline, and (4) more calcareous. Spectral response of soils can be used to evaluate such parameters as moisture content, structure and texture, and chemical and mineralogical content; thereby providing the basis for remote prediction of playa surface characteristics. |
