The aim of the campaign is measuring ground surface temperatures (GST) and their variability at small to medium scale, i.e. within distances of meters to a few kilometers. This is done to support investigations of scaling issues and of model validation. 

For data recording we have chosen iButtons. In order to record GST and avoid heating by direct solar radiation, they were buried approximately 5cm deep into the ground or placed between and underneath big boulders. The iButtons were set to measure temperature every 3h at 0.0625 C resolution enabling operation for 512 days before memory is full. 

Since GST are strongly influenced by topography, 39 locations representing the topographic variability around the mountain Corvatsch in the Upper Engadine, Switzerland were selected. The main topographic variables studied are: elevation ranging from 2100m to 3300m a.s.l., slope from zero degrees to around 50 degrees, all expositions to the sun and material types ranging from fine soil to coarse blocks. Each location is called a footprint and consists of a homogeneous square of 10m by 10m. 

To measure the variation of GST at very small distances, we distributed 10 iButtons randomly within each footprint. This was done by generating a sample of size ten from U(1,100) with R (http://cran.r-project.org/) and placing the iButtons in the respective 10 squares. iButtons were waterproofed by sealing them in customized plastic pouches. A yellow string that was attached to the pouches help to refind the iButtons in the following year and to prevent them from moving down steep slopes. 

All 390 iButtons were efficiently programmed with the management tool iAssist. Important meta data such as fotographs and coordinates were recorded and stored in the data base of the management tool iAssist. The topographic properties were derived from a 10m resolution digital elevation model and are also stored the data base.