Turbulent dispersion observed during the COMTESSA artificial release experiments

Author(s): Anna Solvejg Dinger, Kerstin Stebel, Massimo Cassiani, Hamidreza Ardeshiri, Cirilo Bernardo, Arve Kylling, Soon Young Park, Ignacio Pisso, Norbert Schmidbauer, Andreas Stohl
Abstract: The development of atmospheric dispersion models benefit from comparison with experimental data, both for validation and to constrain parameterizations of underlying physical processes. Atmospheric dispersion is generally difficult to measure directly due to the large range of time and length scales involved. The COMTESSA project (Camera Observation and Modelling of 4D Tracer Dispersion in the Atmosphere) is the first attempt at using ultraviolet (UV) camera observations to sample the three-dimensional (3d) tracer concentration distribution in the atmospheric boundary layer (ABL) around a point source. During two field campaigns in Norway in July 2017 and July 2018, sulfur dioxide (SO₂) was released in continuous plumes and nearly instantaneous puffs from a tower (9 m and 60 m for 2017 and 2018, respectively). Column-integrated SO₂ concentrations were observed with up to six UV SO₂ cameras with sampling rates of several Hertz and a spatial resolution of a few centimetres. The atmospheric flow was characterised by eddy covariance measurements of heat and momentum fluxes at the release mast and up to two additional towers. By measuring simultaneously with multiple cameras positioned in a half circle around the release point, we could collect a dataset of spatially and temporally resolved tracer column densities from up to six different directions, allowing a reconstruction of the concentration field. Here, we show first results demonstrating that three-dimensional turbulent measures can be retrieved from images of artificially released puffs. The absolute dispersion, the relative dispersion and the centre of mass meandering of an ensemble of 37 puffs are characterised using a simplified tomographic approach.
Organisation(s): Department of Meteorology and Geophysics
External organisation(s): Norwegian Institute for Air Research, Scientific Software Center, AIRES Pty Ltd., Gwangju Institute of Science and Technology (GIST)
Publication date: 2019
Peer reviewed: Yes
Austrian Fields of Science 2012: 105206 Meteorology
Keywords
ASJC Scopus subject areas: Atmospheric Science, Pollution, Modelling and Simulation
Portal url: https://ucrisportal.univie.ac.at/en/publications/aa8fc626-4741-4084-ba81-29eea47374ed

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