A moisture index for surface characterization over a semiarid area

A multispectral index, designed to describe surface moisture characteristic s, was derived from the information content at the blue, near-infrared, and thermal wavelengths of Landsat Thematic Mapper imagery. The index is given by an open-ended triangle within which features of varying moisture conten ts are located. Although the index bears some resemblance to existing soil and vegetation indices as well as to the Tasseled Cap transformation, it di ffers in the way in which moisture, brightness, and vegetation information can be expressed in one locational space. The index was found to vary as a function of changes in the season, in vegetation cover, and in moisture con ditions. The index was also found to be sensitive to the spatial resolution at which it was described.