The Evaluation of the Thermal Field under Urban Heat Island Based on Borehole Temperature Measurements (Evidence from Yekaterinburg, Russia)

Abstract

The paper deals with the analysis of the subsurface urban thermal field using temperature logging in boreholes. The method for the separation and quantification of temperature anomalies in an urban subsurface induced by climate change and the building construction at the local area has been described. The differences in the penetration dynamics for climate and local anomalies afford to estimate their contributions separately. The study was carried out by the example of the borehole IGF-280 located in Yekaterinburg, Russia. It was found that the value of local temperature anomaly caused by the building construction is much higher than that induced by climate change (11 K versus 1.4 K). But the climate temperature anomaly penetrates deeper than the local one (140 m for the climate anomaly versus 90 m for the local one). We also assessed changes in heat content due to climatic changes and building operation. The heat content of the rocks increased by 15.6·10⁷ J/m² due to climate change over the past 150 years. The building input to the heat content increase is more than twice as higher – 38.6·10⁷ J/m². About 40% of the heat content gain caused by climate change is concentrated in the 20-meter layer of rocks, and 97% of that – in the upper 100 m. 74% of the heat content gain due to the building influence are concentrated in the upper 20 m.