Ammonia plays a key role in the atmospheric nitrogen cycle as a primary reactive. Our capacity predicting the spatiotemporal distribution of ammonia is hampered by our inability in crossing disciplines, involving biology, meteorology and chemistry. Complexity increases as a result of these processes acting on different scales (field, to the landscape and regional). This PhD project aims to increase our prediction capacity of ammonia by examining the relationships between meteorological drivers and ammonia land-atmosphere exchanges. The main focus of the project is on dry deposition, an important removal process in the ammonia cycle (Sutton et al. 2013). A cross-scale and multi-process approach is proposed, using a state-of-the-art measurement network, and employing a hierarchy of models