Dataset of atmospheric helium tracer experiments and micrometeorological measurements for near-field dispersion analysis in the vicinity of the Beuvry cyclotron (France)
How does a gaseous plume disperse in the presence of buildings, roads, and vegetation? This dataset documents the behaviour of a helium tracer and the wind conditions measured near the Beuvry cyclotron.
Atmospheric dispersion from a gaseous release in the immediate vicinity of a facility depends primarily on atmospheric conditions and on obstacles that shape airflow at the local scale. Buildings, roads, vegetation and local topography can deflect, channel or dilute a plume over distances ranging from a few tens to several hundreds of metres. Understanding these processes is essential for assessing potential population exposure and for testing the ability of dispersion models to represent atmospheric concentrations in built environments.
The DIFLU dataset documents two field campaigns conducted from 14 to 18 October and from 9 to 13 December 2019 near the Beuvry cyclotron, in northern France. Nineteen tracer experiments were carried out by controlled injection of helium-4, an inert gas used as a passive tracer, into the air stream exiting the cyclotron stack. Helium concentrations were then measured at different downwind distances and locations in the near field of the cyclotron, up to approximately 560 m from the stack.
The repository brings together integrated air-sampling data, real-time helium measurements, and meteorological and micrometeorological observations. It includes data from :
- five ultrasonic anemometers
- a meteorological station
- a Doppler wind lidar.
The measurements describe wind speed and direction, turbulence, air temperature, atmospheric pressure, relative humidity and solar radiation. The data are accompanied by variable dictionaries, instrument metadata, instrument coordinates, as well as photographs and videos of the experimental site.
This resource contributes to the study of gaseous-plume dispersion in the atmosphere in built environments. It can be used to compare measurements and simulations, evaluate Gaussian models or simplified near-field dispersion models for an emission source, and test computational fluid dynamics (CFD) simulations. It is also associated with the article by Laguionie et al., published in Atmosphere in 2022, while including additional measurements and documentation.