Modeling the effect of free convection on permafrost melting-rates in frozen rock-clefts

• Main Authors: Sedaghatkish, Amir, Doumenc, Frédéric, Jeannin, Pierre-Yves, Luetscher, Marc
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2024
• Subjects: article; Verlagsveröffentlichung; Ice; permafrost
• Online Access: https://doi.org/10.5194/egusphere-2023-2349; https://noa.gwlb.de/receive/cop_mods_00070797; https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00069127/egusphere-2023-2349.pdf; https://egusphere.copernicus.org/preprints/2024/egusphere-2023-2349/egusphere-2023-2349.pdf

Fully coupled heat transfer modeling during the thawing of frozen rock clefts yields melting rates that differ from those predicted by conventional conduction-based models. This research develops a conceptual model of a karst system subject to mountain permafrost supported by a numerical simulation incorporating free water convection. The numerical simulations rely on the apparent heat capacity method and the Darcy approach for energy and momentum equations. Notably, the anomalous behavior of water between 0 and 4 ℃ causes warmer meltwater to flow downwards, increasing the melting rate by approximately an order of magnitude as compared to conventional models that disregard free convection. The model outcomes are compared qualitatively with field data from Monlesi ice cave (Switzerland) and confirm the close agreement between the proposed model and real-world observations.