Thermal Conductivity Measurement (Tcm) of ice cores: Devices and Procedures

Abstract

An apparatus has been developed expressly to operate at temperatures below 0°C for the determination of the thermal conductivity of ice, which can be measured by the transient hot wire method. Thermal conductivity is determined by tracking the thermal pulse propagation induced in the sample by a heating source consisting of a Pt resistance. A central segment of the same hearing platinum resistance acts as a thermal sensor. The heat impulse transferred to the ice for a period of 40 s gives a maximum temperature increment of about 7-14°C. Each measurement requires a few minutes only. In good experimental conditions, the expected repeatability of the measurements is within ±3 %. The precision of this method depends on whether the instrument has been calibrated by reliable standard samples, certified by absolute methods. A programme of routine measurements of ice cores and a sequence of experimental standard procedures are proposed.