Ground-penetrating radar studies of the permafrost at the new monitoring sites near Novolazarevskaya Station in East Antarctica

The study of permafrost in Antarctic oases is crucial for understanding how the cryolithozone responds to climate change. However, systematic observations of active layer thickness and the permafrost temperature regime remain limited in East Antarctica. This study aims to establish two test sites in different landscapes near the Novolazarevskaya Station (Schirmacher Oasis), to resume monitoring of the permafrost and active layer. The research is based on ground-penetrating radar surveys using 150 MHz and 900 MHz antennas along parallel profiles, and high-precision GNSS positioning. The obtained data was verified through a test pit and thermometry. The average thickness of the active layer has been established as 0.9 m at the “Permafrost 1” site and 1.2 m at the “Permafrost 2” site. Local variations range from 0.3 m beneath the snowfield to 2.0 m beneath a temporary stream. The identified differences are due to a combination of local factors, including the lithological composition of the deposits, micro-relief, and hydrological conditions. Data from the test pit at the “Permafrost 1” site confirmed the presence of a permafrost roof at a depth of 0.8 m. The diurnal temperature range showed stable values of -0.2 ℃ in the permafrost and fluctuations of between 0 ℃ and 2 ℃ in the active layer. Consequently, separate maps of surface topography, permafrost roof, and active layer thickness were created for the two sites. Together with the CALM-S site, the established monitoring sites can serve as a basis for resuming regular, long-term monitoring of the active layer in the Schirmacher Oasis.