Sulphur gas emissions in the boreal forest: the West Whitecourt case study. IV: Air quality and the meteorological environment

A program of atmospheric measurements was carried out in support of the West Whitecourt case study in the summers of 1975 and 1976. Measurements in and around an isolated stand of mature lodgepole × Jack pine trees included temperature, moisture, and wind measurements at a climatological station outside the stand and at several levels on a 30 m radio mast tower within the stand. Sulphur dioxide concentrations were also measured on the tower. A number of short-term, intensive measurements were made to document the meteorological and SO2 environments in more detail, with special attention given to the transport of S gas from the source to the sink. The major source of SO2 at the intensive experimental site was very likely the flare stacks at the gas processing plant. Sulphur dioxide events at the study site were typically daytime, low concentration bursts of a few minutes in duration which occurred with westerly winds under fair weather conditions. Air impinging on the stand tended to flow around the edges of the stand, over the canopy, and into the trunk space. This aerodynamic effect, together with the uptake of SO2 by the vegetation, caused a minimum in SO2 concentration in the crown of the forest.