Séminaire
Understanding the distribution of and control on thermal regime is important for improving our predictive understanding, functioning and evolution of ecosystems, and in particular in the Arctic. A novel method was developed for near surface thermal characterization and potentially monitoring, involving an unprecedented number of laterally distributed and vertically-resolved temperature measurements. This Distributed Temperature Profiling System was used in parallel with Electrical Resistivity Tomography and UAV-based low-altitude aerial optical imaging in a watershed on the Seward Peninsula, near Nome, AK. The distributed temperature profiling enabled the mapping of the distribution of shallow permafrost and was highly valuable to complement Electrical Resistivity Tomography to investigate the presence of deep and shallow permafrost. This study reveals the presence of lateral and sometimes vertical isolated permafrost bodies with the existence of strong lateral gradient in temperature and preferential flow paths in the thaw layer along their edges. Links are observed between subsurface properties and surface microtopography, flow paths, and vegetation type and density. This shows the potential of this integrated characterization approach to advance our understanding of the complex and interacting hydro and thermal processes in the Arctic environment.