1. Atmospheric chemistry and physics in the atmosphere of a developed megacity (London): An overview of the REPARTEE experiment and its conclusionsRoy M Harrison, Manuel DallOsto, David C S Beddows, Alistair J Thorpe, William J Bloss, James D Allan, Hugh Coe, James R Dorsey, Martin W Gallagher, Claire Martin, John Whitehead, Paul I Williams, Roderick L Jones, Justin M Langridge, A K Benton, Stephen M Ball, Ben Langford, C Nicholas Hewitt, Brian Davison, Damien Martin, K Fredrik Peterson, Stephen J Henshaw, Iain R. White, Dudley E Shallcross, Janet F Barlow, Tyrone Dunbar, Fay Davies, Eiko Nemitz, Gavin J Phillips, Carole Helfter, Chiara F Di Marco, Steven Smith, 2012, review article Abstract: The Regents Park and Tower Environmental Experiment (REPARTEE) comprised two campaigns in London in October 2006 and October/November 2007. The experiment design involved measurements at a heavily trafficked roadside site, two urban background sites and an elevated site at 160-190 m above ground on the BT Tower, supplemented in the second campaign by Doppler lidar measurements of atmospheric vertical structure. A wide range of measurements of airborne particle physical metrics and chemical composition were made as well as measurements of a considerable range of gas phase species and the fluxes of both particulate and gas phase substances. Significant findings include (a) demonstration of the evaporation of traffic-generated nanoparticles during both horizontal and vertical atmospheric transport; (b) generation of a large base of information on the fluxes of nanoparticles, accumulation mode particles and specific chemical components of the aerosol and a range of gas phase species, as well as the elucidation of key processes and comparison with emissions inventories; (c) quantification of vertical gradients in selected aerosol and trace gas species which has demonstrated the important role of regional transport in influencing concentrations of sulphate, nitrate and secondary organic compounds within the atmosphere of London; (d) generation of new data on the atmospheric structure and turbulence above London, including the estimation of mixed layer depths; (e) provision of new data on trace gas dispersion in the urban atmosphere through the release of purposeful tracers; (f) the determination of spatial differences in aerosol particle size distributions and their interpretation in terms of sources and physico-chemical transformations; (g) studies of the nocturnal oxidation of nitrogen oxides and of the diurnal behaviour of nitrate aerosol in the urban atmosphere, and (h) new information on the chemical composition and source apportionment of particulate matter size fractions in the atmosphere of London derived both from bulk chemical analysis and aerosol mass spectrometry with two instrument types. Keywords: megacity, trace gas, urban atmosphere, atmospheric transport, chemical composition, aerosol Published in RUNG: 18.07.2019; Views: 4143; Downloads: 0 This document has many files! More... |
2. Tracer concentration profiles measured in central London as part of the REPARTEE campaignDamien Martin, K Fredrik Petersson, Iain R. White, Stephen H Henshaw, Graham Nickless, Amy Lovelock, Janet F Barlow, Tyrone Dunbar, Curtis R Wood, Dudley E. Shallcross, 2011, original scientific article Abstract: There have been relatively few tracer experiments carried out that have looked at vertical plume spread in urban areas. In this paper we present results from two tracer (cyclic perfluorocarbon) experiments carried out in 2006 and 2007 in central London centred on the BT Tower as part of the REPARTEE (Regent's Park and Tower Environmental Experiment) campaign. The height of the tower gives a unique opportunity to study vertical dispersion profiles and transport times in central London. Vertical gradients are contrasted with the relevant Pasquill stability classes. Estimation of lateral advection and vertical mixing times are made and compared with previous measurements. Data are then compared with a simple operational dispersion model and contrasted with data taken in central London as part of the DAPPLE campaign. This correlates dosage with non-dimensionalised distance from source. Such analyses illustrate the feasibility of the use of these empirical correlations over these prescribed distances in central London. Keywords: advection, concentration (composition), dispersion, tracer, urban atmosphere, vertical mixing, vertical profile Published in RUNG: 18.07.2019; Views: 4105; Downloads: 0 This document has many files! More... |