Toward HPC simulations of climate warming impacts on Eurasian permafrost: the HiPerBorea project

• Main Authors: Orgogozo, Laurent, Xavier, Thibault
• Other Authors: Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), ANR-19-CE46-0003,HiPerBorea,Calul haute performance pour la quantification des impacts du changement climatique sur les régions boréales(2019)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2022
• Subjects: heat transfer; water transfer; porous media; high performance computing; permafrost; climate change; Siberia; [PHYS]Physics [physics]; [INFO]Computer Science [cs]; [SDE]Environmental Sciences
• Online Access: https://hal.science/hal-03976656; https://hal.science/hal-03976656/document; https://hal.science/hal-03976656/file/Orgogozo_Xavier_ACFD_2022.pdf; https://doi.org/10.13140/RG.2.2.31820.49289

International audience Permafrost, i.e., soil that is year-round frozen in depth, is covering a quarter of the northern hemisphere lands, and most of it is located in Asia (Siberia, Himalaya). It currently experiences fast changes due to climate change at global scale and technogenic perturbations at local scale, and the assessment and anticipation of these changes are of primary importance for many environmental and engineering applications in cold regions [1],[2] . To these ends, permafrost modeling is required. It implies the numerical simulation of coupled heat and water transfers in variably saturated porous media experiencing freeze/thaw of the pore water. The strong couplings and non-linearities involved in the physics at stake make such simulations highly challenging, especially from a computational point of view, and thus the use of High Performance Computing is needed. This communication aims to illustrate these challenges by considering applications of a recentlydeveloped OpenFOAM ® solver for cryohydrogeology, permaFoam [3],[4] . Developing permaFoam in the OpenFOAM framework allows to benefit from up to date, continuously maintained parallel computing capabilities [5],[6],[7] . Currently permaFoam is developed and used in the framework of HiPerBorea [8] , a research project dealing with the assessment of climate change impacts on permafrost on boreal continental surfaces. It focuses on the numerical simulation of heat andwater fluxes within four boreal catchments under long term environmental monitoring [9] , and which spans a large longitudinal gradient in Eurasia, from Scandinavia to Eastern Siberia. Using permaFoam, HiPerBorea aims to produce simulations of responses of the permafrost of these watersheds for various scenarios of climate change until 2100. Such simulations imply the use of large computational resources, and are performed on tier-0 supercomputers [10] . Thanks to itsgood parallel performances, permaFoam allows using efficiently such HPC facilities. For the on-going academic year ...