In 2012, the investigations on permafrost and ice boreholes were mainly focused on the retrieving of the instrumental data and the maintenance of the instrumentation. These activities were coordinated by the University of Pavia (Department of Earth and Environmental Sciences) and the Office for Geology and Building Materials Testing of the Autonomous Province of Bolzano with the cooperation of the Ohio State University (Byrd Polar Research Center), the University of Padova (Department of Land, Environment, Agriculture and Forestry and Department of Geosciences), the Hydrographic Office of the Autonomous Province of Bolzano and the University of Venezia (Department of Environmental Sciences, Informatics and Statistics).
One of the boreholes drilled in 2011 (borehole n 3) was equipped with two thermistor chains, which regularly recorded the ice temperature from the surface to the base of the glacier (at a depth of about 75 m). The data were downloaded in 2012, during the two surveys of 18 June and 7 September, along with the maintenance of the data logger battery (Figure 1). Negative and nearly stable ice temperatures were recorded throughout the year below a depth of about 35 m, confirming the existence of cold ice in the glacier of Mt. Ortles.
During both the two surveys of 2012, inclinometer measurements were performed in borehole 2, which was previously equipped with an inclinometer pipe (Figure 2). Unfortunately, the inclinometer probe has stopped at a depth of about 25 m, probably because of the presence of an ice layer into the pipe or because of the beak of the pipe. Therefore, the inner deformation of the glacier was fully measured only two times, few days and about a month after drilling respectively. The lengthening of a steel cable which was fastened outside the inclinometer pipe was also measured for the first time. A compaction of the firn of more than 1 m between October 2011 and September 2012 was inferred from this measurement.
The ice temperature data of the thermistor chain that was installed to a depth of about 9 m in the Hintergrat glacier was also downloaded on 28 August, 2012. Very cold ice conditions were observed in this glacier. The ground temperatures of the ice-free areas and the rockwalls near the Ortles summit are currently measured by different types of data loggers, in order to investigate the presence of permafrost and its thermal conditions. In 2010, we placed six data loggers in nearly-flat, debris areas located on the Hintergrat ridge and close to the Lombardi bivac and the Payer hut. The data were retrieved for the first time in 2012, on 28 August at Hintergrat and Payer hut and on 7 September at Lombardi bivac respectively (Figure 3). At the same time, the batteries of the data loggers were replaced and the measurements were relaunched. The data series available up to now cover the period from September 2010 to November 2011 and show cold ground temperatures during winter (between 0°C and -10°C) even under a quite thick snow cover. This provided us a preliminary indication on the presence of permafrost in the sites under investigation. The rock temperature is currently measured at different depths (10, 30, 55 cm from the surface) in five rockwalls.
The data logger were downloaded on 28 August at Hintergrat and at Payer hut and on 7 September at Ortles summit, at Vorgipfel, and at Lombardi bivac. All the instruments have worked well in the first year of measurements and only the device located near the Hintergrat ridge was damaged at the end of July. It was therefore fixed during the survey of 28 August and is currently working (Figure 4). Some data series (Vorgipfel, Ortles summit and Lombardi bivac) cover a full year of measurements and showed negative mean annual rock temperatures (between -2°C and -3°C) from the surface to more than half meter of depth.In the coming years more data will be available, allowing us to observe how the ground temperature is changing in relation to climatic conditions.
Figure 1 – Download of the ice temperature data from the borehole 3 (07/09/2012; photo: R. Seppi)
Figure 2 – Inclinometer measurements at the borehole 2 (07/09/2012; photo: R. Seppi)
Figure 3 – Download operations of a ground temperature data logger placed in debris on the Hintergrat ridge (28/08/2012; photo: D. Tonidandel)
Figure 4 – Fixing operations of the temperature data logger placed in a rockwall on the Hintergrat ridge (28/08/2012; photo: D. Tonidandel)