Accueil > Actualités > Séminaires > Séminaire de Fabio Cresto Aleina au LSCE


Titre : Modeling and upscaling micro-topographic controls on boreal peatland hydrology and methane fluxes Boreal and Arctic ecosystems
Nom du conférencier : Fabio Cresto Aleina
Son affiliation :
Laboratoire organisateur : LSCE
Date et heure : 02-06-2017 11h00
Lieu : Orme des Merisiers; Room 17-C
Résumé :

Small-scale surface heterogeneities can influence land-atmosphere fluxes and therefore carbon, water and energy budgets on larger scale. This effect is of particular relevance for high-latitude ecosystems, because of the great amount of carbon stored in their soils. We introduce two novel micro-topographic model, the Hummock-Hollow (HH) model, representing small-scale surface elevation changes. By computing the water table at the small scale, and by coupling the model with a process-based model for soil methane processes, we are able to model effects of micro-topography on hydrology and methane emissions in a typical boreal peatland. In order to assess the effect of micro-topography on water balance and methane emissions of the peatland we compare two versions of the model, one with a representation of micro-topography and a classical single-bucket model version, and show that the temporal variability in the model version with micro-topography performs better if compared with local data. Accounting for micro-topography almost triples the cumulative methane flux over the simulated time-slice. We found that the single-bucket model underestimates methane emissions because of its poor performance in representing hydrological dynamics. The HH model with micro-topography captures the spatial dynamics of water and methane fluxes, being able to identify the hotspots for methane emissions. The model also identifies a critical scale (0.01 km2) which marks the minimal resolution for the explicit representation of micro-topography in larger-scale models. We also developed a novel approach  to upscale local methane emissions in a boreal peatland from the micro-topographic scale to the landscape-scale.

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