ORCHIDEE MICT-LEAK (r5459), a global model for the production, transport and transformation of dissolved organic carbon from Arctic permafrost regions, Part 2: Model evaluation over the Lena River basin

• Published in: Geoscientific Model Development
• Main Authors: Bowring, Simon, Lauerwald, Ronny, Guenet, Bertrand, Zhu, Dan, Guimberteau, Matthieu, Pierre, Régnier, Tootchi, Ardalan, Ducharne, Agnès, Ciais, Philippe
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université libre de Bruxelles (ULB), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté COMUE (UBFC)-Université Bourgogne Franche-Comté COMUE (UBFC), Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ICOS-ATC (ICOS-ATC), European Project: 643052,H2020,H2020-MSCA-ITN-2014,C-CASCADES(2015), European Project: 703813,H2020,H2020-MSCA-IF-2015,C-LEAK(2016), European Project: 641816,H2020,H2020-SC5-2014-two-stage,CRESCENDO(2015)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: [SDE]Environmental Sciences; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Arctic; Arctic Ocean; lena river; permafrost
• Online Access: https://hal.science/hal-02374036; https://hal.science/hal-02374036/document; https://hal.science/hal-02374036/file/gmd-13-507-2020.pdf; https://doi.org/10.5194/gmd-13-507-2020

International audience In this second part of a two-part study, we performed a simulation of the carbon and water budget of the Lena catchment with the land surface model ORCHIDEE MICT-LEAK, enabled to simulate dissolved organic carbon (DOC) production in soils and its transport and fate in high-latitude inland waters. The model results are evaluated for their ability to reproduce the fluxes of DOC and carbon dioxide (CO 2) along the soil-inland-water continuum and the exchange of CO 2 with the atmosphere, including the evasion outgassing of CO 2 from inland waters. We present simulation results over the years 1901-2007 and show that the model is able to broadly reproduce observed state variables and their emergent properties across a range of interacting physical and biogeochemical processes. These include (1) net primary production (NPP), respiration and riverine hydrologic amplitude , seasonality, and inter-annual variation; (2) DOC concentrations , bulk annual flow, and their volumetric attribu-tion at the sub-catchment level; (3) high headwater versus downstream CO 2 evasion, an emergent phenomenon consistent with observations over a spectrum of high-latitude observational studies. These quantities obey emergent relationships with environmental variables like air temperature and topographic slope that have been described in the literature. This gives us confidence in reporting the following additional findings: of the ∼ 34 Tg C yr −1 left over as input to soil matter after NPP is diminished by heterotrophic respiration, 7 Tg C yr −1 is leached and transported into the aquatic system. Of this, over half (3.6 Tg C yr −1) is evaded from the inland water surface back into the atmosphere and the remainder (3.4 Tg C yr −1) flushed out into the Arctic Ocean, mirroring empirically derived studies. These river-ine DOC exports represent ∼ 1.5 % of NPP. DOC exported from the floodplains is dominantly sourced from recent more "labile" terrestrial production in contrast to DOC leached from the rest of the watershed ...