On most borehole sites air temperatures are measured. Further, vertical arrays of Miniature Temperature Dataloggers (MTDs; Thermochron iButtons®) at fixed heights above the ground surface have been installed to roughly determine the snow depths at the sites, which is also indicated by digital cameras providing daily pictures of snow and weather conditions. Four boreholes are provided with close by probes measuring soil moisture in the upper 65 cm. This is an important parameter for heat flow models. At the uppermost borehole at Tron (Tro-BH1, 1640 m a.s.l.) an automatic weather station was installed September 2008 providing hourly data of air temperature and humidity, wind speed and direction, in- and outgoing short- and longwaved radiation.
At most borehole sites geophysical measurements (electrical resistivity tomogrpahy (ERT) and refraction seismics) have been obtained to indicate the existence of frozen ground and ground ice in the vicinity of the holes. At some of the boreholes repeated ERT measurements has been undertaken on a fixed electrode setup to investigate the degradation/aggradation of ground ice.