During the summer of 2012, the activities on Mt. Ortles were aimed at achieving two main goals: maintenance of the automatic weather station (AWS, Figure 1) and the measurement of the mass balance on the site of the AWS and on the drilling site performed in 2011. These activities were coordinated by researchers of the Department of Land, Environment, Agriculture and Forestry of the University of Padova and of the Department of Agriculture and Environmental Sciences, University of Udine, which have installed the weather station and carry on glaciological and hydrological investigations in the Eastern Italian Alps, mainly focused on the Ortles-Cevedale massif. Investigations were carried out in cooperation with the Byrd Polar Research Center of Ohio State University, the Hydrographic Office of the Autonomous Province of Bolzano, the Department of Earth and Environmental Sciences (University of Pavia), the Department of Geosciences (University of Padova) and the Environmental Science Department (University of Venice)
The AWS has worked perfectly throughout the year 2011-2012, proving to be reliable and resistant to stresses typical of a high-altitude alpine environment (heavy snow, icing, high winds, lightning, etc. ….). On June 18, 2012 we downloaded the recorded data on a laptop. Then the tower that supports the station was temporarily tipped over (Figure 2 ) to allow checking of the status of the sensors and the addition of a data logger (component that serves to record data) and two additional sensors. On September 7 we also checked the functioning of the AWS and downloaded the data as we did in June. In addition, it was necessary to raise the station by adding a module of 2 m to the tower. This was necessary to prevent the equipment (and solar panels that power the AWS) from being buried by new snow accumulation in the coming months. On the AWS site we installed a thermistor chain, that is, a 20 m long cable with temperature sensors at each meter, inserted vertically into the snow to measure the thermal conditions between the surface and 20 m depth.
The mass balance was measured by sounding the thickness of the snow using a metal probe and by digging snowpits (Figure 3) in order to describe the stratigraphy of the snowpack and to measure its density. The stratigraphy (form and size of the snow crystals, presence of layers of ice or dust) serves to distinguish the layers and define their age. All these data are necessary to establish the actual thickness of the snow accumulated in the current year, avoiding errors which can arise from including the snow accumulated in previous years. The density measurements are needed to convert the snow thickness to millimeters of water equivalent, which is a unit of measure generally used to report results and make comparisons with different sites or times.
As you can see in Figure 3, the mass balance for the year 2011-2012 was positive, because accumulation (snowfalls) prevailed over losses (melt). The measurement site indeed lies in a high altitude (3850 m) accumulation area, located above the current equilibrium line altitude, where snow accumulates and gradually transforms into new ice. The analysis of data collected by the AWS will enable a detailed description of the weather conditions and of the evolution of the snowpack during winter 2011-2012, aimed at better understanding the processes occurring on this high-altitude glacial site and the effect of current climatic changes.
Figure 1 – The automatic weather station installed on Mt. Ortles at 3850 m. Description of sensors: 1 = solar panels; 2 = incoming and reflected solar radiation (albedometer); 3 = wind speed and direction; 4 = snow height; 5 = incoming and outgoing infrared radiation; 6 = temperature and relative humidity (aspirated shield); 7 = temperature (naturally ventilated shield).
Figure 2 – The automatic weather station during maintenance. At the bottom right the work is finished and the AWS is ready for the coming winter season.
Figure 3 – The snowpack vertical profile in the pit dug on September 7, 2012. S-2012 and S-2011 are the so-called „summer surfaces“, formed in late summer 2012 and 2011 respectively. The snow which accumulated during the winter and survived to the summer melt lies between S-2011 and S-2012. Above S-2012 you can see the newly fallen snow, between August 30 and September 1, 2012.