Global modeling of nitrogen and phosphorus (terrestrial transport path)
Currently, a model of terrestrial nitrogen (WaterGAP-N) is being developed. For the future, another model for phosphorus is planned.
UNEP's Global Environmental Outlook 2000 recognized that nitrogen pollution has become a global problem that does no longer affect only developed countries. Due to the future increase of population and wealth, and the related extension and intensification of agriculture, many areas of the globe will potentially be subject to high nitrate levels in the groundwater and the eutrophication of surface waters (terrestrial and marine). The purpose of the model WaterGAP-N is to get an overview of the present-day global situation of nitrogen input and fate, and to derive scenarios of the future that simulate the impact of global change (climate, population, agriculture, waste water treatment, etc.). Model design is geared towards making the best use of globally available data.
WaterGAP-N simulates the input and fate of terrestrial nitrogen, including the input from diffuse (industrial fertilizer and manure, biological fixation, and atmospheric deposition) and point sources and the transport of dissolved N and its outgassing by denitrification in the soil and the groundwater as well as in surface waters (rivers, lakes, wetlands). With a spatial resolution of 0.5°, it computes the N loads in each cell as well as the input to the oceans. WaterGAP-N is based on information from the global model of water availability and water use WaterGAP 2.1 (Döll et al. 2003).
Specific research activities
- Modeling of diffuse N-inputs to the soil (synthetic N-fertilizers, manure, biological N-fixation, atmospheric deposition) and N-extractions from the soil (plant uptake, ammonia volatilization). => See Frankfurt Hydrology Paper 2
- Modeling of point sources of nitrogen and phosphorus (diploma theses in progress)
- Modeling of denitrification and N-transport in ground and surface water (ongoing)
