1. Joint Center for Earth Systems Technology; Univ. of Maryland; Baltimore County (UMBC); Baltimore MD 20771 USA
2. Biospheric Sciences Branch, Code 614.4; NASA/Goddard Space Flight Center; Greenbelt MD 20771 USA
3. Hydrology and Remote Sensing Lab., Agricultural Research Service; USDA; Beltsville MD 20705 USA
4. Science Systems and Applications Inc. (SSAI); Lanham MD 20706 USA