Transfers along slopes in a permafrost-dominated watershed of Central Siberia: a mechanistic 2D coupled thermo-hydrological modeling study

• Main Authors: Orgogozo, L., Prokushkin, A, Pokrovsky, O., Godderis, Y., Grenier, C., Quintard, Michel, Viers, J., Labat, D., Audry, S.
• Other Authors: Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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), Laboratoire des Mécanismes et Transfert en Géologie (LMTG), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Centre Scientifique et Technique du Bâtiment (CSTB), Institut de mécanique des fluides de Toulouse (IMFT), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire de Recherche de l'Ecole Nationale Supérieure du Paysage (LAREP), Ecole Nationale Supérieure Polytechnique de Yaoundé (ENSPY), Université de Yaoundé I-Université de Yaoundé I
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2016
• Subjects: [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation; [INFO.INFO-DC]Computer Science [cs]/Distributed; Parallel; and Cluster Computing [cs.DC]; permafrost; Siberia
• Online Access: https://hal.science/hal-01881777

International audience This work presents a numerical study of water and energy transfers within a permafrost dominated experimental watershed of Central Siberia, the Kulingdakan catchment (e.g.: Viers et al., 2015). This watershed has been studied for years in order to characterize and quantify the elementary transfers from the slopes to the stream along the seasonal cycles, and in the context of climate change. The water fluxes, strongly coupled with the thermal fluxes due to the presence of permafrost, are the main vectors of these matter transfers. In this study we aim to build a mechanistic model of the water and energy fluxes that may produce rigorous thermal and hydrological background for modellings the geochemical transfers from the slopes to the stream. The use of a mechanistic approach consists in resolving numerically the governing equations of the considered physical phenomena, established in the framework of continuum mechanics. The tool we used to produce a mechanistic model of the thermo-hydrological transfers in soils is permaFoam (Orgogozo et al., 2015), a solver for the coupled equations that describe unsaturated water transfers (with evapotranspiration) and thermal transfers (with freeze/thaw), implemented in the framework of OpenFOAM®, a well-known open source tool box for computational fluid dynamics. The main interest of using OpenFOAM® lays in its good performances in massively parallel computing (e.g.: Orgogozo et al., 2014). Indeed, due to the strong couplings and the strong non-linearities that are encountered in such physical problems, the use of high performance computing methods is needed to deal with the fine spatial and temporal discretizations required for the numerical resolutions. This is especially true when large scales are involved as is the case for the experimental watershed scale (here, Kulingdakan watershed, about 41 km² of surface).The Kulingdakan watershed is dominated by continuous permafrost, with larch forests growing on soils produced from weathering of basaltic ...