Advective Heat Transport in Frozen Rock Clefts - Conceptual Model, Laboratory Experiments and Numerical Simulation

• Published in: Permafrost and Periglacial Processes
• Main Authors: Hasler, A., Gruber, S., Font, Marianne, Dubois, André
• Other Authors: Glaciology, Geomorphodynamics & Geochronology Group, Universität Zürich Zürich = University of Zurich (UZH), Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: rockfall; numerical modelling; climate change; permafrost; bedrock; conductive heat transfer; advective heat transport; laboratory experiment; geo; envir; Ice; Permafrost and Periglacial Processes
• Online Access: https://doi.org/10.1002/ppp.737; https://hal.archives-ouvertes.fr/hal-00679024

International audience Advective heat transported by water percolating into discontinuities in frozen ground can rapidly increase temperatures at depth because it provides a thermal shortcut between the atmosphere and the subsurface. Here, we develop a conceptual model that incorporates the main heat-exchange processes in a rock cleft. Laboratory experiments and numerical simulations based on the model indicate that latent heat release due to initial ice aggradation can rapidly warm cold bedrock and precondition it for later thermal erosion of cleft ice by advected sensible heat. The timing and duration of water percolation both affect the ice-level change if initial aggradation and subsequent erosion are of the same order of magnitude. The surplus advected heat is absorbed by cleft ice loss and runoff from the cleft so that this energy is not directly detectable in ground temperature records. Our findings suggest that thawing-related rockfall is possible even in cold permafrost if meltwater production and flow characteristics change significantly. Advective warming could rapidly affect failure planes beneath large rock masses and failure events could therefore differ greatly from common magnitude reaction-time relations.