MPeat2D - A fully coupled mechanical-ecohydrological model of peatland development in two dimensions

Mahdiyasa, Adilan Widyawan; Large, David John; Icardi, Matteo; Muljadi, Bagus Putra

Abstract

Higher dimensional models of peatland development are required to analyse the influence of spatial heterogeneity and complex feedback mechanisms. However, the current models exclude the mechanical process that leads to uncertainties in simulating the spatial variability of water table position, vegetation composition, and peat physical properties. Here, we propose MPeat2D, a peatland development model in two dimensions, which considers mechanical, ecological, and hydrological processes together with the essential feedback from spatial interactions. MPeat2D employs poroelasticity theory that couples fluid flow and solid deformation to model the influence of peat volume changes on peatland ecology and hydrology. To validate the poroelasticity formulation, the comparisons between numerical and analytical solutions of Mandel’s problems for two-dimensional test cases are conducted. The application of MPeat2D is illustrated by simulating peatland growth over 5000 years above the flat and impermeable substrate with free-draining boundaries at the edges, using constant and variable climate. In both climatic scenarios, MPeat2D produces lateral variability of water table depth, which results in the variation of vegetation composition. Furthermore, the drop of the water table at the margin increases the compaction effect, leading to a higher value of bulk density and a lower value of active porosity and hydraulic conductivity. These spatial variations obtained from MPeat2D are consistent with the field observations, suggesting plausible outputs from the proposed model. By comparing the results of MPeat2D to a one-dimensional model and a two-dimensional model without the mechanical process, the significance of mechanical-ecohydrological feedback on spatial heterogeneity, peatland shape, carbon accumulation, and resilience is highlighted.

Citation

Mahdiyasa, A. W., Large, D. J., Icardi, M., & Muljadi, B. P. MPeat2D - A fully coupled mechanical-ecohydrological model of peatland development in two dimensions

• Working Paper Type: Working Paper
• Deposit Date: Jul 5, 2024
• Publicly Available Date: Jul 5, 2024
• Publisher: European Geosciences Union
• Public URL: https://nottingham-repository.worktribe.com/output/27079137
• Publisher URL: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2535/