We investigate the temperature conditions inside the Earth. Temperature data from depths of hundreds of meters to the first kilometres below the Earth’s surface are acquired by direct temperature measurements in boreholes, while temperature conditions at greater depths are estimated by calculations based on information about long-term ground surface temperature, temperature change with depth, thermal conductivity of rocks, and heat generation in the Earth’s interior. The equipment for this research includes a portable thermometer for borehole temperature logging to the depth of 2–3 km, data loggers with temperature sensors for continuous temperature monitoring at several depth levels (down to 190 m), laboratory instruments for measurements of thermal conductivity and diffusivity of rocks and soils, and a gamma-spectrometer for a content measurements of radioactive isotopes of uranium, thorium and potassium in rocks, the decay of which is the main heat source within the Earth. The research is supported by up-to-date software packages for a complex numerical the solution of the heat transfer equation and temperature calculations in geothermal lithospheric models, including a solution of 2-D and 3-D problems. The research is carried out mostly in our geothermal network GeoCLIMANET, which consists of permanent experimental boreholes located both in the Czech Republic and abroad. The department also participates in a number of research activities both with domestic and international partners.
Head of the department: Jan Šafanda
The department currently focuses on five main research topics:
Improvement of the terrestrial heat flow map of the Czech Republic – Although the Czech Republic is among the best geothermally investigated countries, there still exist areas that are explored insufficiently. These regions are of particular significance in the effort to refine the heat flow data, which are needed for regional studies. Therefore, deep borehole temperatures are measured in new locations and existing data is revised, particularly in order to correct them for the effect of the last glacial period that makes the measured heat flow values depth-dependent.
Ground surface temperature reconstructions – Long-term variations of ground surface temperature propagate into bedrock through the heat transfer mechanism. Analysis of precise temperature logs in several hundred meters deep boreholes and their mathematical processing allows the reconstruction of the main trends of ground surface temperature in the last few centuries. This method is an independent source of information about past climate changes, which is necessary to understand and model the present and future climates.
Study of the coupling between air, ground and bedrock temperatures – Monitoring of air, ground (with different surface covers) and bedrock temperatures is established at the observatories in the Czech Republic (Praha, Kocelovice, Svojšice), Slovenia (Malence) and Portugal (Evora-Caravelinha). The processing and interpretation of unique data acquired at these stations improves our understanding of the atmosphere-solid Earth heat exchange, which has both purely scientific (e.g. climatology, meteorology, pedology, permafrost research) and practical applications (e.g. study of heat loss of buildings or geothermal sources for heat pumps).
Application of knowledge of a thermal regime of the Earth’s crust to studies of geothermal energy utilization – Knowledge of a thermal regime and geothermal conditions in individual regions of the Czech Republic can be utilized to assess the geothermal energy potential. Temperature at the depth of heat pumping is the key parameter considered for projects in specific locations. A precise geothermal model of the site allows for a physically-based estimate of the project viability.
Research of permafrost, active layer and periglacial landforms – The distribution and dynamics of permafrost and the active layer are important indicators of present climate changes as well as in the youngest geological history. Their evolution is examined with simple analytical tools and complex numerical models designed to solve the heat transfer in the Earth’s crust based on transient upper boundary conditions (ground surface temperature, glaciation, sea-level fluctuations) and considering the ice-water phase change. Distribution and morphology of periglacial landforms is also investigated, with particular focus on the structures emerging in the presence of permafrost and allowing (palaeo) climate interpretation.