Investigations of the air - ground temperature coupling at location of the Malence borehole near Kostanjevica, SE Slovenia
AbstractIn this paper we present the results of monitoring of temperatures in the air, soil and a borehole V-8/86 at Malence near Kostanjevica in the southeast Slovenia. The results include the temperatures measured in the period from year 2011 to 2015. Highlights of the paper are mainly on the influence of heavy rainfall on temperatures in the upper parts of the shallow subsurface, on understanding how the heat transfers between air and soil and in determination of the warming rate in the shallow subsurface with the assumption that conduction is the prevalent mechanism of heat transfer within the rock. The analysis has shown that heavy rainfall has a greater impact at depth of 1 m in the borehole than at 1 m in the soil, since the sensor at 1 m in the borehole is actually still in the air (inside the borehole) so the rainwater and consequently the air temperature change can reach it faster than the rainwater can infiltrate through soil to depth of 1 m. During infiltration the rainwater's temperature interact with the soil temperature and the change between the rainwater and soil temperatures is no longer evident at 1 m depth in the soil. Based on the measured temperatures from years 2014 and 2015 the rate of warming at the depth of 40 m is 0.011 °C/yr. While analysing the temperature-depth profile of daily means of temperature on the 15th day of each month, we concluded that the influence of seasons can be tracked down to depth of 20 m. At the depth of 20 m temperatures vary within 0.04 °C (2015). The assumption that the conduction is the prevalent mechanism of heat transfer is reasonable, because the theoretical values do not differ much from the measured ones (within 5 %).
How to Cite
Strgar, A., Rajver, D., & Gosar, A. (2017). Investigations of the air - ground temperature coupling at location of the Malence borehole near Kostanjevica, SE Slovenia. Geologija, 60(1), 129–143. https://doi.org/10.5474/geologija.2017.010