Landsat thermal images to estimate the dynamics of northeast Siberian mountain permafrost landscapes

International audienceShifting landscape boundaries is one of the long-term consequences of climate change. The transitional ecosystems between the arctic tundra and boreal forests in the mountains are open systems for the impact of climate change. The spread of continuous permafrost in these landscapes also accelerates the response of the ecosystem to climatic fluctuations. Thus, the bio productivity and boundaries of permafrost landscapes change in accordance with the dynamics of energy supply and humidity. This study presents the results of modelling the dynamics of the transitional permafrost landscapes between tundra and boreal forests of the Orulgan ridge in North-East Siberia. The modelling is based on the integration of Landsat 7 and 8 thermal infrared images. The methodology used is based on the analysis of mountain tundra areas with climatic characteristics close to boreal landscapes according to long-term data from WorldClim. These data show a positive trend in mean temperature and a negative trend in total precipitation. The distribution of landscape types on the territory of the ridge is associated with relief, which determines the contrast of climatic conditions on a local scale. The Land Surface Temperature (LST) extracted from thermal remote sensing data is a critical parameter in assessing the energy balance of mountain permafrost landscapes at the local level. Therefore, in the selected test area, we analysed the correlation between the land cover change from 1999 to 2020 with the extracted LST from Landsat 7 ETM+ and 8 TIRS thermal images. We found that the advance of forests on the tundra most often occurs on the slopes of the southern exposure with a significant increase in LST and a gentle slope of diluvial deposits and solifluction. Thus, we have determined the possibilities of using thermal images in assessing the impact of climate change in the Arctic mountainous territories of the permafrost zone with natural landscape dynamics, with a low intensity of anthropogenic impact and in conditions of remoteness from meteorological stations