Nest-DNDC is an integration of Northern Ecosyste Soil Temperature (NEST) model and DNDC that upscales methane fluxes from plant communities to ecosystem scale in permafrost peatlands. Information is exchanged between the two models at code level, so the model is able to simulate the interaction between biogeochemical process and soil thermal-hydrological conditions.
NEST-DNDC simulates an ecosytem domain that is made up of many plant communities, which share common weather and geological conditions but vary in their biophysical factors. An area-weighted sum of plant community fluxes can calculate ecosystem scale fluxes. A simulated deep ground profile captures changes in summer thaw depth, variations of permafrost with climate and provides a lower boundary condition for water table depth.
NEST-DNDC is also able to siumulate upland and wetland ecosystems without permafrost. The modelled soil profile can contain may different soil textures and layers of varying thickness and gravel content. The model can be applied to a wide range of ecosystems from forest to tundra, as it can model an upper- and understory of woody plants, a layer of sedges or grass and a layer of mosses.Changes of bubble volume in the soil profile (based on the ideal gas law and Henry's Law) were tracked using a newly developed ebullition module. Model results were in agreement with those measured by closed chamber and eddy covariance method for the Lena River Delta, Russia. Zhang et al. (2012) found the model to be capable of upscaling methane fluxes to larger scales.