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Abstract
Accurate models of turbulent dispersion are required for simulating the near-field concentration distribution of pollutants. However, high-resolution measurements of turbulent dispersion in the atmospheric boundary layer are sparse. This thesis describes the three artificial release experiments in the summers of 2017-2019 within the comtessa (Camera Observation and Modelling of 4D Tracer Dispersion in the Atmosphere)project and presents derived results for the turbulent dispersion of tracer puffs. Instantaneous puffs of sulfur dioxide (SO2) were released from a tower on a military site in Norway. Column-integrated SO2 concentrations were observed with SO2 cameras from up to six viewing directions while the atmospheric flow was characterised by eddy covariance measurements at different altitudes along the release tower. A novel simplified tomographic approach was applied to reconstruct the dispersion of tracer puffs separated into their centre of mass trajectories and their dispersion around the centre of mass. Using ensembles of puff releases, the meandering, relative and absolute dispersion as well as the Lagrangian velocity autocorrelations were measured. The ratio of Lagrangian and Eulerian time scales was estimated to a lower bound of TL/TE = 0.33 * 1/i where i is the turbulence intensity; agreeing with previous studies.
Document type: | Dissertation |
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Supervisor: | Platt, Prof. Dr. Ulrich |
Place of Publication: | Heidelberg |
Date of thesis defense: | 8 January 2020 |
Date Deposited: | 11 Feb 2020 14:53 |
Date: | 2020 |
Faculties / Institutes: | The Faculty of Physics and Astronomy > Institute of Environmental Physics |
DDC-classification: | 500 Natural sciences and mathematics 530 Physics 550 Earth sciences |
Controlled Keywords: | Atmospheric physics, Turbulence, Dispersion, SO2 camera, Atmospheric boundary layer |