A subsiding regional forest fire aerosol layer at Whistler, BC: implications for interpretation of mountaintop chemistry observations
1Department of Geography, The University of British Columbia, Vancouver, Canada
2Department of Chemistry, The University of British Columbia, Vancouver, Canada
3Centre for Atmospheric Research Experiments, Environment Canada, Egbert, Canada
4Science and Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto, Ontario, Canada
Abstract. On 30 August 2009, intense forest fires in interior BC, together with synoptic scale meteorological subsidence and easterly winds resulted in transport of a broad forest fire plume across southwestern BC. The physico-chemical and optical characteristics of the plume as observed from Saturna island (AERONET), CORALNet-UBC and the Whistler Mountain air chemistry facility were consistent with forest fire plumes that have been observed elsewhere in continental North America. However, the importance of smoke plume subsidence in relation to the interpretation of mountaintop chemistry observations is highlighted on the basis of deployment both a CL31 ceilometer and a single particle mass spectrometer (SPMS) in a mountainous setting. The SPMS was used to identify the biomass plume based on levoglucosan and potassium markers. Data from the SPMS are also used to show that the biomass plume was correlated with nitrate, but not correlated with sulphate or sodium. This study not only provides baseline measurements of biomass burning plume physico-chemical characteristics in western Canada, but also highlights the importance of lidar remote sensing methods in the interpretation of mountaintop chemistry measurements.