Monitoring changes in debris-cover extent on Miage glacier, Italian Alps, between 1975-2006 using optical and thermal satellite imagery

Identification of debris-cover extent and its change over time on glaciers is an important challenge within the framework of GLIMS (Global Land Ice Measurements from Space) project. Methods based on multispectral analyses are hampered due to the spectral characteristics of supraglacial debris, which are similar to surrounding non-glacial terrain. To resolve this, previous studies have applied manual approaches through on-screen digitising of debris-covered areas. Despite promising results, this method is labour intensive and time consuming, especially for a large number of glaciers. Consequently, semi-automatic methods have been developed. This study tests the applicability of both manual digitizing and a semi-automatic approach (Paul et al., 2004) to the debris-covered Miage glacier. Results are positive but show only a small increase in the areas of continuous debris cover between 1990-2004, implying the transition to extensive debris-cover on this glacier occurred prior to 1990.