Rock temperature variability in high-altitude rockfall-prone areas

Abstract

In a context of cryosphere degradation caused by climate warming, rock temperature is one of the main driving factors of rockfalls that occur on high-elevation mountain slopes. In order to improve the knowledge on this critical relationship, it is necessary to: i) increase measurement capability for rock temperature and its variability in different lithological and slope/aspect conditions; ii) increase local scale studies; iii) increase the quality and the comparability of the observational data. This paper shows an example of metrological characterization of sensors used for rock temperature measurement in mountain regions aiming at establishing. Metrological traceability and evaluating measurement uncertainty. Under such approach, data and results from temperature measurements carried out in the Bessanese high-elevation experimental site (Western European Alps) are illustrated. The here adopted procedures for the calibration and field characterization of sensors allow to measure temperature in different locations, depths and litotypes within 0.098 °C of overall uncertainty. The main results are: i) Metrological traceability is fundamental to asses data quality and establish comparability among different measurements; ii) There are strong differences between air temperature and near-surface rock temperature; iii) There are significant differences of rock temperature acquired in different aspect conditions. Solar radiation, slope/aspect conditions and lithotype, seem to be the main driving factors of rock temperature.

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