PARENT SESSION
Organized Oral Session 13: Gas exchange and global change in peatlands: From soil to satellite
Organizer(s): J Limpens, G Schaepman, MB Nilsson, and MM Heijmans
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 510b, Level 5, Palais des congrès de Montréal

Modelling peatland carbon exchanges from the scale of individual ecosystems to the globe.

Roulet, Nigel^{*,1, 5}, Frolking, Steve⁴, Ouyang, Bing^{1, 5}, St-Hilaire, Francois¹, Lafleur, Peter², Richard, Pierre^{3, 5}, ¹ Geography, Montreal, QC, Canada⁵ Global Environmental and Climate Change Centre, Montreal, QC, Canada⁴ Complex Systems, EOS, Durham, NH, United States of America² Geography, Peterborough, ON, Canada³ Geographie, Montreal, QC, Canada

ABSTRACT- Northern peatland slowly accumulate carbon (atmospheric CO₂) and emit methane (CH₄), therefore the determination of their role as a net greenhouse sink/source is not straight forward. Past and contemporary strengths of the CO₂ and CH₄ net exchanges are a function of the peatland type, age, biogeochemistry, internal hydrology and the peatlands physical setting in the landscape. Over the last few years we have developed several models that simulate contemporary and past exchange of CO₂ and CH₄ from northern peatlands as a function of climate. To help develop and evaluate the models we have also maintained a continuous measured program of greenhouse gas exchange and dissolved organic carbon export from a raised ombrotrophic bog in the cool temperate ecoclimatic region of eastern Canada. We have coupled the surface climate model, Wetland CLASS, to the Peatland Carbon Simulator, (PCARS) a peatland ecosystem biogeochemistry model. These two models individually and coupled capture the daily, seasonal, annual and interannual variability displayed in the observational records of the energy, water and carbon exchanges. A second generation couple surface climate peatland model, the New Peatland Model (NPM), is being developed with enough process details to mimic the essential features of carbon cycling while being simple enough for use in global coupled climate-carbon simulations. In addition we have developed a long-term carbon accumulation model, the Peat Accumulation Model (PAM) that has be evaluated against reconstructed accumulation rates from peat cores while reproducing the mean annual contemporary water balance, CO₂ uptake and CH₄ release. PAM is being used to examine the interaction between peatland carbon dynamics and climate over centuries to millennia.

Key words: peatlands, modelling, carbon dioxide, methane