Wetness Dynamics and Permafrost Thaw Across the Arctic: An Integrated Analysis based on In-Situ and Satellite-Based Soil Moisture Datasets

The rapid thawing of Arctic permafrost is driving significant changes in both the hydrological and carbon cycles, with critical implications for surface wetness and ecosystem processes. These changes are contributing to increased surface wetness, which, in turn, accelerates permafrost degradation and alters ecosystem dynamics. Understanding the feedback mechanisms governing these processes is essential for predicting future impacts, as seasonal variations in wetness directly influence permafrost stability and carbon fluxes. This study integrates in-situ measurements and satellite-based observations to investigate wetness variability across the Arctic, providing a comprehensive assessment.

In-situ soil moisture records, collected across diverse permafrost regions in North America and Eurasia, were combined with high-resolution land cover data from the circumarctic Land Cover Units (CALU) v2.0 dataset and other variables (ground temperature etc.) from ESA CCI Permafrost records. This approach aims to identify the processes and key drivers of wetness variability and quantify wetting/drying trends. To gain deeper insights into the mechanisms governing these dynamics, land cover is incorporated as a critical variable to understand its role in influencing wetness dynamics, including processes such as vegetation growth and permafrost thaw including related disturbances. Statistical analyses were conducted to assess biases in satellite-based soil moisture retrievals and to evaluate the significance of the observed trends. Preliminary findings reveal considerable biases in satellite retrievals.

Further on, surface deformation and subsidence are associated with permafrost thaw. They can be investigated with interferometric synthetic aperture radar (InSAR) utilizing data from e.g. Sentinel-1 and ALOS-2 PALSAR. These deformation patterns provide critical insights into surface wetness. The findings of this study advance understanding of the current and future impacts of climate change on Arctic ecosystems, particularly in relation to surface wetness dynamics, permafrost stability, and land-atmosphere interactions.