Proceedings of the 1999 Ieee International Geoscience and Remote Sensing Symposium (Igarss'99) 'Remote Sensing of the Systems Earth - A Challenge for the 21St Century', Date: 28 June 1999 through 2 July 1999, Location: Hamburg, Ger, Sponsors: IEEE Geoscience and Remote Sensing Society;University of Hamburg;NASA;NOAA