Long-term dynamics of the thermal state of technogenic territories of gold deposits mining in Siberia based on satellite data

We have studied the dynamics of relative anomalies in the ground cover thermal regime of technogenic territories under the conditions of gold mining impact for 20 years in Central Siberia. Impact of gold deposits mining causes landscape changes and disturbances of vegetation and soil covers. This determines the change in the thermal state of the post-industrial plots for a long time, which is an important feature of ecosystem stability monitoring.

We analyzed the spectral characteristics of three post-technogenic sites, where quarries were recorded in different years. The test sites are located in the taiga zone of Central Siberia. We used free banks of satellite imagery for 2000–2020 (USGS, https://earthexplorer.usgs.gov/, accessed on 21 May 2022), such as Landsat-5/7 (channels 5-4-3) and Landsat-8 (channels 6-5-4).

After using the standard calibration procedure, we evaluated and averaged the surface temperature (λ = 10.4–12.5 μm, Landsat-5,7/TM/ETM and λ = 10.6–11.19 μm, Landsat-8/OLI). We recorded the excess of temperature in disturbed areas by 70-90% relative to background (no vegetation cover in such areas, physical evaporation increases, soil moisture decreases). We analyzed the temperature dynamics in the disturbed areas in relation to background values for summer periods during 20–40 years.

We controlled the state and recovery of technogenic sites according to data on i) the initial level of thermal anomaly, ii) the rate of decrease in temperature in post-technogenic plots in the first 5–10 years, iii) the time of stabilization of recovery processes (~20–40 years), iv) the residual level of thermal anomaly (~15%).

We can assume that in most cases of post-technogenic territories, “neotechnogenic ecosystems” are formed with special thermal regimes that differ from the background ones for a long time. The type of reclamation determines the duration and significance of such changes at the level of the Siberian taiga ecosystems.