Methane emissions from floodplains in the Amazon Basin: challenges in developing a process-based model for global applications

Autor: Ringeval, B., Houweling, S., Van Bodegom, P. M., Spahni, R., Van Beek, R., Joos, F., Röckmann, T., Dep Natuurkunde, Hydrologie, Sub Atmospheric physics and chemistry, Marine and Atmospheric Research, Landscape functioning, Geocomputation and Hydrology
Přispěvatelé: Systems Ecology, Amsterdam Global Change Institute, Interactions Sol Plante Atmosphère (UMR ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), SRON Netherlands Institute for Space Research (SRON), Vrije Universiteit Amsterdam [Amsterdam] (VU), Climate and Environmental Physics [Bern] (CEP), Physikalisches Institut [Bern], Universität Bern [Bern]-Universität Bern [Bern], Faculty of Geosciences, Utrecht University [Utrecht], Oeschger Centre for Climate Change Research (OCCR), University of Bern, Institute for Marine and Atmospheric Research [Utrecht] (IMAU), Interactions Sol Plante Atmosphère (ISPA), Dep Natuurkunde, Hydrologie, Sub Atmospheric physics and chemistry, Marine and Atmospheric Research, Landscape functioning, Geocomputation and Hydrology
Rok vydání: 2014
Předmět:
plaine d'inondation
Floodplain
Evolution
530 Physics
WETLAND EXTENT
[SDE.MCG]Environmental Sciences/Global Changes
lcsh:Life
Wetland
ATMOSPHERIC METHANE
Land cover
modèle
Atmospheric sciences
écosystème tropical
Hydrology (agriculture)
Behavior and Systematics
lcsh:QH540-549.5
NET PRIMARY PRODUCTION
SDG 13 - Climate Action
BIOGEOCHEMISTRY MODEL
méthane
Milieux et Changements globaux
amérique du sud
550 Earth sciences & geology
Ecology
Evolution
Behavior and Systematics
Earth-Surface Processes
Hydrology
geography
geography.geographical_feature_category
Ecology
Amazon rainforest
VEGETATION MODEL
lcsh:QE1-996.5
Primary production
Vegetation
15. Life on land
Dynamic global vegetation model
TERRESTRIAL ECOSYSTEMS
LAST GLACIAL MAXIMUM
COMPARISON PROJECT WETCHIMP
RIVER FLOODPLAIN
NORTHERN PEATLANDS
lcsh:Geology
lcsh:QH501-531
13. Climate action
Environmental science
lcsh:Ecology
Zdroj: Biogeosciences 6 (11), 1519-1558. (2014)
Ringeval, B H, Houweling, S, van Bodegom, P M, Spahni, R, van Beek, R, Joos, F & Röckmann, T 2014, ' Methane emissions from floodplains in the Amazon Basin: challenges in developing a process-based model for global applications ', Biogeosciences, vol. 2014, no. 11, pp. 1519-1558 . https://doi.org/10.5194/bg-11-1519-2014
Biogeosciences
Biogeosciences, Vol 11, Iss 6, Pp 1519-1558 (2014)
Biogeosciences, 11(6), 1519. European Geosciences Union
Biogeosciences, 2014(11), 1519-1558. European Geosciences Union
Biogeosciences, European Geosciences Union, 2014, 11 (6), pp.1519-1558. ⟨10.5194/bg-11-1519-2014⟩
Ringeval, B.; Houweling, S.; van Bodegom, P. M.; Spahni, Renato; van Beek, R.; Joos, Fortunat; Röckmann, T. (2014). Methane emissions from floodplains in the Amazon Basin: challenges in developing a process-based model for global applications. Biogeosciences, 11(6), pp. 1519-1558. Copernicus Publications 10.5194/bg-11-1519-2014
ISSN: 1726-4189
1726-4170
Popis: International audience; Tropical wetlands are estimated to represent about 50 % of the natural wetland methane (CH 4) emissions and explain a large fraction of the observed CH 4 variability on timescales ranging from glacial–interglacial cycles to the currently observed year-to-year variability. Despite their importance , however, tropical wetlands are poorly represented in global models aiming to predict global CH 4 emissions. This publication documents a first step in the development of a process-based model of CH 4 emissions from tropical flood-plains for global applications. For this purpose, the LPX-Bern Dynamic Global Vegetation Model (LPX hereafter) was slightly modified to represent floodplain hydrology, vegetation and associated CH 4 emissions. The extent of tropical floodplains was prescribed using output from the spatially explicit hydrology model PCR-GLOBWB. We introduced new plant functional types (PFTs) that explicitly represent floodplain vegetation. The PFT parameterizations were evaluated against available remote-sensing data sets (GLC2000 land cover and MODIS Net Primary Productivity). Simulated CH 4 flux densities were evaluated against field observations and regional flux inventories. Simulated CH 4 emissions at Amazon Basin scale were compared to model simulations performed in the WETCHIMP intercomparison project. We found that LPX reproduces the average magnitude of observed net CH 4 flux densities for the Amazon Basin. However , the model does not reproduce the variability between sites or between years within a site. Unfortunately, site information is too limited to attest or disprove some model features. At the Amazon Basin scale, our results underline the large uncertainty in the magnitude of wetland CH 4 emissions. Sensitivity analyses gave insights into the main drivers of floodplain CH 4 emission and their associated uncertainties. In particular, uncertainties in floodplain extent (i.e., difference between GLC2000 and PCR-GLOBWB output) modulate the simulated emissions by a factor of about 2. Our best estimates, using PCR-GLOBWB in combination with GLC2000, lead to simulated Amazon-integrated emissions of 44.4 ± 4.8 Tg yr −1. Additionally, the LPX emissions are highly sensitive to vegetation distribution. Two simulations with the same mean PFT cover, but different spatial distributions of grasslands within the basin, modulated emissions by about 20 %. Correcting the LPX-simulated NPP using MODIS reduces the Amazon emissions by 11.3 %. Finally, due to an intrinsic limitation of LPX to account for season-ality in floodplain extent, the model failed to reproduce the full dynamics in CH 4 emissions but we proposed solutions to this issue. The interannual variability (IAV) of the emissions increases by 90 % if the IAV in floodplain extent is accounted Published by Copernicus Publications on behalf of the European Geosciences Union. 1520 B. Ringeval et al.: Methane emissions from floodplains in the Amazon Basin for, but still remains lower than in most of the WETCHIMP models. While our model includes more mechanisms specific to tropical floodplains, we were unable to reduce the uncertainty in the magnitude of wetland CH 4 emissions of the Amazon Basin. Our results helped identify and prioritize directions towards more accurate estimates of tropical CH 4 emissions, and they stress the need for more research to constrain floodplain CH 4 emissions and their temporal variability , even before including other fundamental mechanisms such as floating macrophytes or lateral water fluxes.
Databáze: OpenAIRE
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