Assessment of new spectral indices and multi-seasonal ASTER data for gypsum mapping

Abstract Advanced spaceborne thermal emission and reflection radiometer (ASTER) data different spectral indices were employed to map gypsum minerals. However, most proposed are designed based on the 2.21 ?m absorption, overlapping with hydroxy-bearing Moreover, seasonal mutual transformation between gypsum, bassanite, anhydrite may lead reflectance variability of formation pixels, affecting classification accuracy indices. In this research, feasibility 2.26 (ASTER band7) absorption for mapping was assessed, using lab ASTER reflectance. On basis this, two new (GI 1 : B4*B8/B6*B7; GI 2 B4*B8/B7*B7) applied exclude interference hydroxyl-bearing minerals effectively. Seasonal pixels confirmed, it causes difference multi-seasonal data. The achieves robust average areas under receiver operator characteristic (ROC) curve 98.5% 98.7% summer winter Therefore, can be used mineral mapping, especially in where clay other hydroxyl-containing widely distributed.