Author(s)

D. Tonnesen

Abstract

Dispersion experiments using tracer gas technique were carried out in Oslo during stable stratification and calm wind conditions. Three sets of data were collected, from a street canyon, from an open area with high houses, and across a valley with cold-air drainage flow. The tracer gas release was set up as a line-source in the two first cases, and as point-sources using two different tracers in the third case. Vertical concentration profiles were measured by balloon in the first case and with a drone in the two last cases. The horizontal and vertical tracer gas concentration profiles have been parameterized using a gaussian type dispersion model. The experiments show that the vertical dispersion caused by vehicle induced turbulence is considerable even during stable stratification, and that there can be considera

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