Advanced spaceborne thermal emission and reflection radiometer (ASTER) data and different spectral indices were employed to map gypsum minerals. However, most proposed gypsum indices are designed based on the 2.21 μm gypsum absorption, overlapping with most hydroxy-bearing minerals. Moreover, the seasonal mutual transformation between gypsum, bassanite, and anhydrite may lead to seasonal reflectance variability of gypsum formation pixels, affecting the classification accuracy of gypsum indices. In this research, the feasibility of 2.26 μm (ASTER band7) reflectance absorption for gypsum mapping was assessed, using lab and ASTER reflectance. On the basis of this, two new ASTER gypsum spectral indices (GI¹: B4*B8/B6*B7; GI²: B4*B8/B7*B7) were proposed and applied to exclude the interference of hydroxyl-bearing minerals effectively. Seasonal reflectance variability of gypsum formation pixels was confirmed, and it causes the accuracy difference of gypsum indices for multi-seasonal ASTER data. The GI¹ achieves the most robust accuracy for multi-seasonal ASTER data with average areas under receiver operator characteristic (ROC) curve of 98.5% and 98.7% for summer and winter ASTER data. Therefore, the GI¹ can be used for gypsum mineral mapping, especially in the areas where clay minerals and other hydroxyl-containing minerals are widely distributed.

使用先进的星载热发射和反射辐射计 (ASTER) 数据和不同的光谱指数来绘制石膏矿物图。然而，大多数提议的石膏指数是根据 2.21 微米的石膏吸收设计的，与大多数含羟基矿物重叠。此外，石膏、白蜡石和硬石膏之间的季节性相互转换可能导致石膏地层像素的反射率季节性变化，影响石膏指数的分类精度。在这项研究中，使用实验室和 ASTER 反射率评估了 2.26 μm（ASTER 波段7）反射吸收用于石膏测绘的可行性。在此基础上，两个新的 ASTER 石膏光谱指数 (GI ¹ : B4*B8/B6*B7; GI ²：提出并应用B4*B8/B7*B7)，有效排除含羟基矿物的干扰。石膏地层像素的季节性反射率变异性得到了证实，这导致了多季节ASTER数据的石膏指数精度差异。GI ¹实现了多季节 ASTER 数据的最稳健准确度，夏季和冬季 ASTER 数据的接收器操作员特征 (ROC) 曲线下平均面积分别为 98.5% 和 98.7%。因此，GI ¹可用于石膏矿物测绘，特别是在粘土矿物和其他含羟基矿物广泛分布的地区。