ORCHIDEE-PEAT (revision 4596), a model for northern peatland CO2, water, and energy fluxes on daily to annual scales

0494148 - ÚVGZ 2019 RIV DE eng J - Článek v odborném periodiku
Qiu, C. - Zhu, D. - Ciais, P. - Guenet, B. - Krinner, G. - Peng, S. - Aurela, M. - Bernhofer, C. - Brümmer, C. - Bret-Harte, S. - Chu, H. - Chen, J. - Desai, A. R. - Dušek, Jiří - Euskirchen, E. S. - Fortuniak, K. - Flanagan, L. B. - Friborg, T. - Grygoruk, M. - Gogo, S. - Grünwald, T. - Hansen, B. U. - Holl, D. - Humphreys, E. - Hurkuck, M. - Kiely, G. - Klatt, J. - Kutzbach, L. - Largeron, C. - Laggoun-Defarge, F. - Lund, M. - Lafleur, P. M. - Li, X. - Mammarella, I. - Merbold, L. - Nilsson, M. B. - Olejnik, Janusz - Ottosson-Lofvenius, M. - Oechel, W. - Parmentier, F. J. W. - Peichl, M. - Pirk, N. - Peltola, O. - Pawlak, W. - Rasse, D. - Rinne, J. - Shaver, G. - Schmid, H. P. - Sottocornola, M. - Steinbrecher, R. - Sachs, T. - Urbaniak, M. - Zona, D. - Ziemblinska, K.
ORCHIDEE-PEAT (revision 4596), a model for northern peatland CO2, water, and energy fluxes on daily to annual scales.
Geoscientific Model Development. Roč. 11, č. 2 (2018), s. 497-519. ISSN 1991-959X. E-ISSN 1991-9603
Institucionální podpora: RVO:86652079
Klíčová slova: net primary production * land-surface model * changing climate conditions * litter decomposition rates * carbon-dioxide exchange * last glacial maximum * temperate bog * interannual variability * hydraulic conductivity * ecosystem respiration
Obor OECD: Geology
Impakt faktor: 5.154, rok: 2018

Peatlands store substantial amounts of carbon and are vulnerable to climate change. We present a modified version of the Organising Carbon and Hydrology In Dynamic Ecosystems (ORCHIDEE) land surface model for simulating the hydrology, surface energy, and CO2 fluxes of peatlands on daily to annual timescales. The model includes a separate soil tile in each 0.5 degrees grid cell, defined from a global peatland map and identified with peat-specific soil hydraulic properties. Runoff from non-peat vegetation within a grid cell containing a fraction of peat is routed to this peat soil tile, which maintains shallow water tables. The water table position separates oxic from anoxic decomposition. The model was evaluated against eddy-covariance (EC) observations from 30 northern peatland sites, with the maximum rate of carboxylation (V-cmax) being optimized at each site. Regarding short-term day-to-day variations, the model performance was good for gross primary production (GPP) (r(2) = 0.76, Nash-Sutcliffe modeling efficiency, MEF = 0.76) and ecosystem respiration (ER, r(2) = 0.78, MEF = 0.75), with lesser accuracy for latent heat fluxes (LE, r(2) = 0.42, MEF = 0.14) and and net ecosystem CO2 exchange (NEE, r(2) = 0.38, MEF = 0.26). Seasonal variations in GPP, ER, NEE, and energy fluxes on monthly scales showed moderate to high r(2) values (0.57-0.86). For spatial across-site gradients of annual mean GPP, ER, NEE, and LE, r(2) values of 0.93, 0.89, 0.27, and 0.71 were achieved, respectively. Water table (WT) variation was not well predicted (r(2) < 0.1), likely due to the uncertain water input to the peat from surrounding areas. However, the poor performance of WT simulation did not greatly affect predictions of ER and NEE. We found a significant relationship between optimized V-cmax and latitude (temperature), which better reflects the spatial gradients of annual NEE than using an average V-cmax value.
Trvalý link: http://hdl.handle.net/11104/0287406