| 17 Dec 2024
Review and Synthesis: Peatland and Wetland Models Simulating CH4 Production, CH4 Oxidation and CH4 Transport Pathways
Abstract. Peatlands play an important role in the global CH4 cycle and models are key tools to assess global change effects on CH4 processes. It remains unclear how well our existing wetland modelling frameworks are suited to peatland questions. Therefore, we reviewed 16 peatland or wetland models operating at different spatial (seconds-to-decadal) and temporal (soil core-to-global) scales, having different spin-up periods for carbon pool stabilization and various CH4 production, oxidation and transport processes. Through a literature review, model specific advantages and limitations, common and specific driving inputs of all models and critical inputs of individual models impacting CH4 plant-mediated transport, diffusion and ebullition were summarized. The 16 reviewed models were qualitatively ranked 0 to 4 (none-to-full process representations) with respect to CH4 production, oxidation and transport. The most common temporal and spatial scale for 14 models was daily time-step and field scale respectively, while the spin-up stabilization periods of different carbon pools (peat, litter, roots, exudates, microbial, humus, slow, fast) of all models ranged 7 to 90102 years. With regards to CH4 production and oxidation, 50 % of reviewed models (Ecosys, CLM-Microbe, ELM-Spruce, Peatland-VU, Wetland-DNDC, TRIPLEX-GHG, TEM, CLM4Me) exhibited full to adequate process representation. Meanwhile 44, 44 and 25 % models exhibited full to adequate process representation for plant mediated transport, diffusion and ebullition respectively. This meant there is ample scope to improve ebullition processes in the remaining 75 % models. We conclude that existing models are adequate for site-level CH4 flux assessments but may lack a predictive understanding of CH4 production pathways.
