Project
Nationaal Kennisprogramma Stikstof (NKS-SAGEN)
Within this project, uncertainties in nitrogen deposition on nature areas are addressed. Together with Dutch knowledge institutes, we scrutinizemodelling tools and look at the measurement network. Specifically, we investigate the use of ensembles of models, and the use of satellite data to complement surface observations. At our group we perform high-resolution simulations, focusing on deposition of ammonia near large point sources. In addition, we work on optimization techniques to estimate emissions and optimize measurement networks.
In the Netherlands, nature areas are suffering from excess deposition of reactive nitrogen. Following a policy advise of “Commission Hordijk”, the NKS program tries to better quantify the uncertainties associated with the policy tools that are used to determine deposition of reactive nitrogen. Concerning modelling, the use of an ensemble of models is investigates. Concerning measurements, the use of satellite data to estimate emissions of oxidized and reduced nitrogen species is investigated.
Within NKS, WUR contributes to several projects. Using high-resolution simulations, we study the dispersion and deposition of ammonia close to large point sources. To this end, deposition and chemistry of ammonia will be simulated in high detail, providing a “digital twin” of the transport, chemistry and deposition of reactive nitrogen. These simulations support a benchmark study that is conducted with six policy support models.
Figure 1 shows the effect of using a “compensation point” in the description of ammonia deposition over a grassland (labelled “bi-directional”). The lower panel shows that, according to the calculation (wind 3 m/s), 5.7% of the emitted ammonia is deposited at 6.4 km from the source when a one-directional scheme is used. With the bi-directional scheme, this number is 3.2%.
