Advective heat transport in frozen rock clefts: Conceptual model, laboratory experiments and numerical simulation

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...

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Bibliographic Details
Main Authors: Hasler, A, Gruber, S, Font, M, Dubois, A
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2011
Subjects:
Ice
Online Access:https://www.zora.uzh.ch/id/eprint/58874/
https://www.zora.uzh.ch/id/eprint/58874/1/2011_Hasler_etal.pdf
https://doi.org/10.5167/uzh-58874
https://doi.org/10.1002/ppp.737
Description
Summary: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.