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Imaging radar for ecosystem studies atellites vastly extend the sur-veillance of Earth's surface. Often, however, the view from space is obscured by clouds, which prevent remote sensing with optical or thermal sensors. Because of cloud cover and other inherent limitations of optical and thermal sensors, many important ecosystem properties re-lated to structural features of the vegetation and surface moisture con-ditions cannot be adequately as-sessed. As an alternative, microwave sensors (imaging radar) have longer wavelengths (from 1 cm to 150 cm) that penetrate the densest cloud cover and are particularly sensitive to the presence of water. To date the principal applications of imaging radar have been the mapping of geologic features and the following of seasonal changes in sea-ice. Recently a number of satel-lites have been launched with radar sensors, thus expanding opportunities for global assessments …