The new remote-sensing-derived Swiss glacier inventory: II. First results

Abstract

Complete Swiss glacier inventories are available for 1850 (reconstructed) and 1973 (from acrial photography). Connected to the Global Land Ice Measurements from Space project, a new Swiss glacier inventory for approximately the year 2000 (SGI 2000) is compiled mainly based on satellite imagery. The developed and applied remote- sensing and geographical information system (GIS) methods are described in part I of the contribution. In part II, the inventory design, first-result analyses and comparisons with former glacial conditions are presented. As basic entries SGI 2000 contains the individual glacier identification, planimetric glacier boundaries as derived from image analysis, digitized central flowlines and polygonal glacier basin maps. All other parameters are automatically deduced from the above entries and a digital elevation model within a GIS. Here, we analyze a set of small Bernese and Valais glaciers of area <10 km2. These glaciers lost about 21% of area from 1973 to 1998, in addition to about 80% during 1850 1973, both with respect to the 1973 area. In order to track the latest trend in more detail, an intermediate glacier condition has been compiled from satellite imagery of 1985. This analysis gave an increasing speed of area loss (19%) for 1985 98.