Repeated temperature logs from the sites of the Czech, Slovenian and Portuguese borehole climate stations

International audienceTwo borehole climate stations were established in Slovenia and Portugal within a joint Czech-Slovenian-Portuguese project in the years 2003?2005. They completed the older Czech station, which has been operating since the year 1994. We report here on the repeated temperature logs carried out within 6 boreholes at the sites of the stations and their surroundings within a time span of 8?20 years (1985?2005). The repeated logs revealed subsurface warming in all the boreholes amounting to 0.2?0.6°C below the depth of the annual run at 20 m. The depth of the Czech borehole (140 m) and the Portuguese borehole (180 m) was sufficient enough for a reconstruction of the ground surface temperature (GST) history of the last 150?200 years and their comparison with the surface air temperature (SAT) series measured in Prague (since 1771) and Lisbon (1856), respectively. The reconstructed histories reproduce reasonably well the amplitude of the recent warming, 1?1.5°C above the long-term mean. The depth of all four Slovenian boreholes, 100 m, did not allow the inversion, but it was possible to apply it to a deep borehole 5 km apart from the Slovenian station. The obtained GST history was compared with SAT series from Ljubljana (since 1851). Alternatively, a compatibility of the observed temporal changes of subsurface temperature with surface air temperature series measured in Prague, Ljubljana and Lisbon was checked by comparing differences of the repeated logs with the synthetic ones. These were calculated by using the SAT series as a forcing function at a surface of transient geothermal models of the borehole sites. A degree of agreement varies from very well to rather poor, probably depending on unaccounted site specific factors, which are to be specified by a long-term temperature monitoring at the established stations

Repeated temperature logs from Czech, Slovenian and Portuguese borehole climate observatories

Two borehole climate observatories were established in Slovenia and Portugal within a joint Czech-Slovenian-Portuguese project in the years 2003-2005. Together with the older Czech observatory, which has been operating since the year 1994, they monitor air, soil and bedrock temperatures with the aim of studying air-ground coupling and the downward propagation of the surface temperature changes. We report here on repeated temperature logs carried out within 6 boreholes at the sites of the observatories and their surroundings within a time span of 8–20 years (1985–2005). The repeated logs revealed subsurface warming in all the boreholes amounting to 0.2–0.6°C below 20 m depth. The compatibility of the observed temporal changes of subsurface temperature with surface air temperature (SAT) series measured in Prague (since 1771), Ljubljana (since 1851) and Lisbon (since 1856) was checked by comparing repeated temperature logs with synthetic profiles that were calculated using SAT series as forcing functions. The depth of the Czech borehole (140 m) and the Portuguese borehole (180 m) was sufficient for a reconstruction of the ground surface temperature (GST) history of the last 150–200 years. Reconstructed GSTs were compared with the SAT series measured in Prague and Lisbon, respectively. The reconstructed histories reproduce reasonably well the amplitude of the recent warming inferred from the meteorological data, 1–1.5°C above the long-term mean. The depth (100 m) of the four repeatedly logged Slovenian boreholes was too shallow for inversion, but a climatic reconstruction was carried out for a deeper borehole, logged in 2006 and located within 5 km from the Slovenian observatory. The obtained GST history was compared with SAT series from Ljubljana

A new database structure for the IHFC Global Heat Flow Database

Periodic revisions of the Global Heat Flow Database (GHFD) take place under the auspices of the International Heat Flow Commission (IHFC) of the International Association of Seismology and Physics of the Earth's Interior (IASPEI). A growing number of heat-flow values, advances in scientific methods, digitization, and improvements in database technologies all warrant a revision of the structure of the GHFD that was last amended in 1976. We present a new structure for the GHFD, which will provide a basis for a reassessment and revision of the existing global heat-flow data set. The database fields within the new structure are described in detail to ensure a common understanding of the respective database entries. The new structure of the database takes advantage of today's possibilities for data management. It supports FAIR and open data principles, including interoperability with external data services, and links to DOI and IGSN numbers and other data resources (e.g., world geological map, world stratigraphic system, and International Ocean Drilling Program data). Aligned with this publication, a restructured version of the existing database is published, which provides a starting point for the upcoming collaborative process of data screening, quality control and revision. In parallel, the IHFC will work on criteria for a new quality scheme that will allow future users of the database to evaluate the quality of the collated heat-flow data based on specific criteria

Borehole thermal energy storage applications and in-situ thermal response test - Example from Turkey and situation in Slovenia [Shranjevanje toplote z geosondami in testi za ugotavljanje toplotnih lastnosti zemlje. Primer uporabe v Turciji ter stanje v Sloveniji]

In the paper we present a method of seasonal heat storage with boreholes and thermal response test for determination of ground parameters. Analysis methods for concrete calculations of thermal conductivity as well as error determination are explained. In the continuation measurements made in research of the ground in Turkey and situation in a field of seasonal thermal energy storage in Slovenia are presented. © 2004 Journal of Mechanical Engineering. All rights reserved

Borehole thermal energy storage applications and in-situ thermal response test - Example from Turkey and situation in Slovenia

WOS: 000224541100004In the paper we present a method of seasonal heat storage with boreholes and thermal response test for determination of ground parameters. Analysis methods for concrete calculations of thermal conductivity as well as error determination are explained. In the continuation measurements made in research of the ground in Turkey and situation in afield of seasonal thermal energy storage in Slovenia are presented. (C) 2004 Journal of Mechanical Engineering. All rights reserved