We carried out three artificial tracer release measurement campaigns in the summers of 2017, 2018 and 2019 at the Rena military facility in Eastern Norway. During the campaigns, we released SO2 as an artificial tracer that could be measured downwind from a release mast (10-m high in 2017; 60-m high in 2018 and 2019) that was set up at the site. During the first two experiments, SO2 was blown upward from bottles located at the ground through a pipe. We made both continuous releases over extended time periods (~30 min) as well as near-instantaneous puff releases. To facilitate even shorter puffs, we filled balloons with SO2, pulled them up the mast, and exploded them there during 2019. The release mast, and another mast, were equipped with eddy covariance systems at different heights to measure turbulent fluctuations of the wind.
Sketch of release tower with positions of sonic anemometers and release pipe and image-inlets of the release. In 2019, the balloon cage and additional line (blue) was placed and the canister (green) was connected to the line instead of the pipe. Sketch is not to scale. (Image credits to H. Ardeshiri). [Figure 4.4. of Dinger, 2020]
The Figure below shows example images from plume and puff releases. The left panel shows a plume release from the first campaign in 2017, where the camera was placed ca. 150 m away from the release mast. the right panel shwos a puff release from 2019, The camera was ca. 570 m away from the mast.