A stabilized vegetation index and several mineralogic indices defined for ASTER VNIR and SWIR data

ASTER is composed of three subsystems, each of which multispectrally observes the reflected or emitted radiation from the surface of the earth to space in VNIR (visible and near infrared), SWIR (shortwave infrared) and TIR (thermal infrared) wavelength regions, respectively. Here in this paper, problems in applying the widely used vegetation index, NDVI, to remotely sensed radiance at the sensor data without atmospheric corrections are discussed, and a stabilized vegetation index against the fluctuation factors in the radiance at the sensor data is proposed. Then, reflectance spectra of minerals in SWIR region measured in the laboratory are analyzed to define calcite index, OH-bearing altered minerals index, kaolinite index and alunite index for discriminating the minerals by ASTER-SWIR. The defined indices are applied to ASTER Level-1B radiance at the sensor data multi-temporally observing Cuprite area in Nevada, USA. Discussions are made on the results, especially on the effectiveness of the stabilized vegetation. Also, the applied results of the defined mineralogic indices are compared with the well-known geology of the area.