Local scale modelling of reactive nitrogen dispersion

Facing the Dutch Nitrogen Crisis, the Netherlands needs precise insights into nitrogen deposition. Nitrogen emissions are primarily driven by intensive agriculture, including concentrated livestock farming and extensive fertilizer use. These activities result in a surplus of reactive nitrogen, causing eutrophication and threatening biodiversity. Here, ammonia is a key component. Ammonia accounts for three-quarters of the country's total nitrogen deposition. The NKS (National Nitrogen Knowledge Program) work plan is a comprehensive research initiative financed by the Netherlands' Ministry of Agriculture, Nature, and Food Quality, aimed at reducing uncertainties in nitrogen deposition determinations. Our project, embedded within Work Package 2.2 of this program, introduces an advanced method for accurate deposition modelling. The aim is to combine Large Eddy Simulation (LES) with the DEPAC scheme for accurate deposition modelling. To realistically model the chemical removal of ammonia in the atmosphere, we aim to use a tool for automating the generation of chemical kinetic equations for simulating atmospheric chemistry (KPP) and a thermodynamic model that predicts the phase state and composition of inorganic aerosols based on environmental conditions (ISORROPIA II). This integrated approach, focusing on the area where grassland meets forest, is designed to significantly improve the accuracy of local (resolution of less than 1 km) ammonia deposition assessments. This effort aligns with a part of Benchmark Ensemble Modelling Protocol's intercomparison of policy models. This initiative hopes to aid in refining nitrogen deposition models and support the formulation of science-based environmental policies.