Monitoring Glacier Changes with the Use of Archive Images: The Example of the Julian Alps (NW Slovenia, NE Italy)

Abstract

In the last century and a half, average summer temperatures have slowly been rising worldwide. The most observable consequence of this is the change in glacier sizes. For monitoring glacier area and volume, various measuring techniques exist—from measurements with a measuring tape and geodetic measurements to remote sensing and photogrammetry. Many of these techniques were used to monitor very small glaciers in the Julian Alps through the twentieth century. At least eight very small glaciers existed in Julian Alps in the previous century. Since the second half of the twentieth century some have disappeared, but some still exist. In this chapter we focus on three small glaciers: two on Mount Canin (NE Italy) and one on Mount Triglav (NW Slovenia). We present the changes in glacier sizes since the end of the nineteenth century with the use of archived non-metrical images. The acquisition is based on interactive orientation method (mono-plotting) using detailed digital terrain models (DTM).

In the studied period, the Canin and Triglav glaciers behaved in a similar manner and also had similar sizes. At the end of the nineteenth century, the Western Canin Glacier covered 28 ha, the Eastern Canin Glacier 13 ha, and the Triglav Glacier 22 ha. By the mid-twentieth century, the glaciers had already broken up into several parts. The Western Canin Glacier covered 7.6 ha in 1957 and the Triglav Glacier covered 13.7 ha in 1958. In 2000, the eastern (largest) part of the Western Canin Glacier and the Triglav Glacier measured 5 ha and 1.1 ha respectively. Since then they have lost at least half their size.

The article highlights the usefulness of archival imagery for long-time monitoring of glaciers.