Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.659984
Title: Modelling spatial and temporal patterns of ozone concentrations around a high-latitude urban area
Author: Nicholson, James P. G.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2001
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Abstract:
A Lagrangian column model, featuring a detailed description of vertical mix­ing, has been developed to simulate the three-dimensional structure in ozone and nitrogen oxides (NOx) concentrations in the boundary-layer, within and down­wind of high-latitude urban areas. The short time-scale photochemical processes of ozone and NOx, as well as emissions and deposition to the ground, are simu­lated. This has been used to follow a range of one-dimensional trajectories, over a distance of 100km and a travel time in the order of 104s, through a simulated city under a variety of meteorological and pollutant emission regimes representing seasonal and diurnal extremes. An assessment of the extent of ozone destruction occurring, the rate of recovery of surface ozone concentrations downwind of the city and the influence of meteorological parameters on the ozone concentration, has been provided using the model. The model, with a spatial resolution of 1x1km, is also applied over a l00xl00km domain containing a simulation of the NOx emission field from the city of Edin­burgh, UK (at latitude 560N) to simulate the two-dimensional city-scale processes of pollutants. Results are presented, using averaged wind-flow frequencies and appropriate stability conditions, to show the extent of the depletion of ozone by the city. The long-term average spatial patterns in the surface ozone and NOx concentrations over the model domain are reproduced quantitatively and are compared with observations from a series of monitoring sites on a north-south trajectory through the city and into rural areas. The model shows the average surface ozone concentrations in the urban area to be lower than the surrounding rural areas by typically 50% and that the areas experiencing a 20% ozone de­pletion over background values are generally restricted to within the boundaries of the urban area. From vertical profiles of ozone concentrations, the depletion of ozone to less than 50% of the rural surface values generally extends not more than 20m vertically above the urban area.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.659984  DOI: Not available
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