Glacial retreat in the 1980s in the Breonie, Aurine and Pusteresi groups (eastern Alps, Italy) in Landsat TM images

In the Italian Alps, the majority of glaciers are small (less than 1 km 2 ), but cover a significant glaciated surface area, despite the fact that ground surveys have only dealt with the major glaciers. Analysis of some Landsat TM images taken at the end of the ablation season highlighted retreat modes in the 1980s on all glaciers in the Breonie, Aurine and Pusteresi groups (eastern Alps)-an area in which, in the early 1980s, large glaciers were advancing and small ones receding. A fuzzy set procedure used to identify glacier surfaces was based on integrated use of Landsat TM images and topographic data in a multisource decision making scheme (applied to bands 1, 3 and 5) to combine information derived from elevation, exposure and morphological aspects. Between 1985 and 1987, the loss of glaciated surface was almost 4 km 2 (total area 33.04 km 2 ), the greatest retreat being found for the largest glaciers (>1 km 2 ). Between 1987 and 1989, the loss was less than 1 km 2 and mostly involved small glaciers (0.5-0.05 km 2 ). Quantitative assessment of glacial evolution on large areas shows inside opposite trends which generally escape ground observation on selected glaciers and which may lead to improved estimation of water resources.