PARENT SESSION
Poster Session 17: Modelling
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Comparing two dynamic ecosystem models' descriptions of N-emissions (CoupModel and PnET-N-DNDC) using data from a spruce forest in Hoeglwald, Germany.
Norman, Josefine*,1, Jansson, Per-Erik2, Butterbach-Bahl, Klaus3, Klemedtsson, Leif1, 1 Göteborg University, Gothenburg, Sweden2 The Royal Institut of Technology, Stockholm, Sweden3 Fraunhofer Institute for Atmospheric Environmental Research (IFU), Garmisch-Partencirchen, Germany
ABSTRACT- The potential of a soil to form and emit nitrogen gases (N2O, NO and N2), increases with increasing abundance of available N. The amount of gases emitted depends on interactions between soil properties, climatic factors, and soil management. Such complex systems require mathematical modelling for understanding the dynamics of ecosystems. To increase the understanding of carbon and nitrogen processes in soil ecosystems, the CoupModel (coupled heat and mass transfer model for soil-plant-atmosphere systems) and DNDC model are important tools. Both models are dynamic models with different submodels for the soil, the vegetation, the hydrology and the climate system. The CoupModel has a higher degree of details on the soil physical and the abiotic components whereas the DNDC model has been putting more focus on the microbiological part and the N-emission component. To improve the previous simple submodel of N-emission in the CoupModel we have recently included a submodel that corresponds to the DNDC model that corresponds to the PnET-N-DNDC model. The CoupModel has been parameterized with respect to the parameter values in the PnET-N-DNDC model. Climate and soil data from a spruce forest in Hoeglwald, Germany, have been used for analysing differences between the two models regarding emissions of NO and N2O from nitrification and denitrification. The validation output in the simulations have been soil temperature at five depths, the water filled poor space at two depths and the emission rates of NO and N2O. Sensibility analyses of the CoupModel indicate that soil temperature and soil water content are very important for both the description of the anaerobic balloon and the estimated diffusion from the anaerobic sites to the aerobic sites from which the transport to the atmosphere occurs. It was possible to demonstrate the separate importance on the production of NO and N2O gases as well as their transport to the atmosphere. The amounts of NO and N2O formed during nitrification are more directly related to their production and less sensitive to the transport in the soil.
Key words: denitrification, modelling, N-emission, nitrification