Satellite Imagery Applications for Hydrogeology
Information from space–based sensing and imaging systems has been widely available in digital format from the mid-1970s. The systems for processing and viewing digital image data became more readily available in the 1980s. This information has been used for such diverse hydrologic purposes as analysis of distribution of hydrogeologic units; estimation of areal extent, depth, and sediment content of water in lakes and streams; distribution, health, and abundance of riparian and phreatophytic vegetation; establishment of environmental baselines; estimation of ocean temperatures; and investigations for occurrence of water on other planets. Much of the preliminary analysis is now automated using commercially available processing software. Processed images can be used to describe hydrologic features and may require calibration through ground truthing. Time series images from earliest availability to the present provide information for numerical analysis of changes in hydrologic features.