In this study, a new methodology for a spatial NH<SUB>3</SUB> emissions inventory for the UK has been developed. In contrast to previous methodologies, the new approach employs a spatial model specifically tailored to NH<SUB>3</SUB>, rather than a more general allocation of agricultural sources (livestock and crop categories). Key model input data are agricultural census data (updated to 1996), average nitrogen fertiliser application rates to crops and grassland, landcover data and NH<SUB>3 </SUB>source strength estimates. A major aim of this thesis was to identify sources of uncertainty in NH<SUB>3</SUB> emission inventories, both at the national and at the local scale. While previous studies only considered uncertainties in the applied NH<SUB>3</SUB> source strength estimates, all main sources of uncertainty in the model input data as well as the model assumptions were evaluated here, and quantified where possible. The main causes of uncertainty in the national inventory were found to be due to spatial aggregation effects (MAUP), and due to the spatial and temporal variability in source strength, depending on environmental conditions and agricultural practice. A quantitative assessment of the modelled spatial variability within the 5 km NH<SUB>3</SUB> emission estimates was carried out by calculating the % coefficient of variation of from the underlying 1 km results. High values of >150% were found in areas with intensive pig and poultry farming, as well as at the boundary between intensively farmed lowland areas and extensive upland and hill areas. Low values of ~20% are typical for some grassland areas with predominantly cattle farming.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:649709 |
| Date | January 1999 |
| Creators | Dragosits, Ulrike |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/22161 |
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