Dispersion experiments with tracer gas in Oslo, Norway

摘要

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 considerable deviation in transport directions during drainage-flow situation depending on the location of the source within the valley.