The Copenhagen tracer experiment, what did we learn?

The Copenhagen tracer experiment was carried out in 1978/79 under neutral and unstable atmospheric conditions in order to study the dispersion process in a built-up area. The tracer sulphurheaxfluoride was released without buoyancy from a tower at a height of 115 meters, and then collected at ground-level positions 2 to 6 km from the point of release.

Some of the shortcomings and strengths that have emerged on the experiment and the data-set will be discussed, especially with respect to the use of the measurements in the light of the recent findings on the structure of the urban boundary-layer.

A large number of models for atmospheric dispersion have been developed since the measurements were carried out, and a main achievement of the data has been to act as basis for validation of new developments in dispersion models, and even today the data are being used.

Major findings from the experiment, and an overview on the use in the last 30 years will be given.