Matrix-based sensitivity assessment of soil organic carbon storage : a case study from the ORCHIDEE-MICT model
Huang, Yuanyuan (Laboratoire des Sciences du Climat et de l'Environnement)
Zhu, Dan (Laboratoire des Sciences du Climat et de l'Environnement)
Ciais, Philippe (Laboratoire des Sciences du Climat et de l'Environnement)
Guenet, Bertrand (Laboratoire des Sciences du Climat et de l'Environnement)
Huang, Ye (Laboratoire des Sciences du Climat et de l'Environnement)
Goll, Daniel (Laboratoire des Sciences du Climat et de l'Environnement)
Guimberteau, Matthieu (Laboratoire des Sciences du Climat et de l'Environnement)
Jornet-Puig, Albert (Laboratoire des Sciences du Climat et de l'Environnement)
Lu, Xingjie (Northern Arizona University. Centerfor Ecosystem Science and Society)
Luo, Yiqi (Tsinghua University. Department of Earth System Science)

Date:	2018
Abstract:	Modeling of global soil organic carbon (SOC) is accompanied by large uncertainties. The heavy computational requirement limits our flexibility in disentangling uncertainty sources especially in high latitudes. We build a structured sensitivity analyzing framework through reorganizing the Organizing Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE)-aMeliorated Interactions between Carbon and Temperature (MICT) model with vertically discretized SOC into one matrix equation, which brings flexibility in comprehensive sensitivity assessment. Through Sobol's method enabled by the matrix, we systematically rank 34 relevant parameters according to variance explained by each parameter and find a strong control of carbon input and turnover time on long-term SOC storages. From further analyses for each soil layer and regional assessment, we find that the active layer depth plays a critical role in the vertical distribution of SOC and SOC equilibrium stocks in northern high latitudes (>50°N). However, the impact of active layer depth on SOC is highly interactive and nonlinear, varying across soil layers and grid cells. The stronger impact of active layer depth on SOC comes from regions with shallow active layer depth (e. g. , the northernmost part of America, Asia, and some Greenland regions). The model is sensitive to the parameter that controls vertical mixing (cryoturbation rate) but only when the vertical carbon input from vegetation is limited since the effect of vertical mixing is relatively small. And the current model structure may still lack mechanisms that effectively bury nonrecalcitrant SOC. We envision a future with more comprehensive model intercomparisons and assessments with an ensemble of land carbon models adopting the matrix-based sensitivity framework.
Grants:	European Commission 610028
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Published in:	Journal of Advances in Modeling Earth Systems, Vol. 10, Issue 8 (August 2018) , p. 1790-1808, ISSN 1942-2466

DOI: 10.1029/2017MS001237
PMID: 31031883

19 p, 4.4 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CREAF (Centre de Recerca Ecològica i d'Aplicacions Forestals) > Imbalance-P
Articles > Research articles
Articles > Published articles