NARROW-BAND ANGULAR REFLECTANCE PROPERTIES OF THE ALKALI FLATS AT WHITE-SANDS, NEW-MEXICO

Results from helicopter measurements of the angular properties of surf ace reflectance for the alkali flats regions of the White Sands Missil e Range are presented for the wavelength interval of 0.4 to 0.85 mu m. This work was performed to allow accurate radiative transfer calculat ions over the region. Detailed tables and interpolation equations are given that permit other investigators to perform satellite calibration s over the alkali flats site. The effects of wavelength and soil moist ure on narrowband angular reflectance are also investigated. Although there is a spectral variation in surface albedo, there is little spect ral effect in Anisotropic Factor except in the forward-scattering peak at solar zenith angles greater than 60 degrees. The magnitude of the forward-scattering peak is also sensitive to soil moisture, with wet c onditions causing a larger peak. The significance of this result is th at angular reflectance properties at the center of the alkali flats us ually will be different than those at the flats edge because moisture differences typically exist.