What is DigiBog?
The full DigiBog is a process-based peatland development model that simulates the accumulation of peat over decadal to millennial timescales. The model can be run in 1D or 2D/3D. The 2D/3D version couples the peat accumulation model from the 1D version and a physics-based model of water flow (i.e. it is fully ecohydrological) to simulate the growth of a peatland over landscape scales. During a simulation, peat layers are built up in hydrologically-connected columns that define the modelled landscape. DigiBog can be used to investigate the impact on peat accumulation (plant litter addition minus peat decomposition) of future climate and land uses over timescales that go beyond what is possible for field experiments.
The model writes out several variables during and at the end of a simulation. These outputs include the height of each peat column (the height of the peatland surface), water-table depth, the hydraulic conductivity of the layers making up each peat column, the degree of decomposition of these layers, and the types of plant remains making up each layer.
DigiBog was originally developed by Andy Baird, Paul Morris, and Lisa Belyea following Lisa's and Andy's work describing peatlands as complex adaptive systems (Belyea and Baird, 2006). Their aim was to simulate key cross-scale peatland processes by coupling ecological and hydrological processes in space as well as in time. The model has since been worked on by Dylan Young and Pete Gill and now incorporates several land uses, up to four plant functional types, and an algorithm to substantially reduce model run times and enable it to run over landscape scales. Previous versions of the model code are freely available from this website under a GNU General Public Licence.
The hydrological part of the full 2D/3D DigiBog exists as a stand-alone model called DigiBog_Hydro. This can simulate water-table dynamics over peatland landscapes and can be used to explore how different types of management (e.g. ditch drainage and ditch blocking) affect the hydrological 'behaviour' of a peatland. Currently, a simple-to-use version of the model is being developed as part of the NERC iCASP project. The update to DigiBog_Hydro is being done in conjunction with the Moors for the Future Partnership and the Yorkshire Peat Partnership and will be freely available via this website.