Ground-based remote sensing of an elevated forest fire aerosol layer at Whistler, BC: implications for interpretation of mountaintop chemistry

摘要

On 30 August 2009, intense forest fires in interior British Columbia (BC)coupled with winds from the east and northeast resulted in transport of abroad forest fire plume across southwestern BC. The physico-chemical andoptical characteristics of the plume as observed from Saturna Island(AERONET), CORALNet-UBC and the Whistler Mountain air chemistry facilitywere consistent with forest fire plumes that have been observed elsewhere incontinental North America. However, the importance of three-dimensionaltransport in relation to the interpretation of mountaintop chemistryobservations is highlighted on the basis of deployment of both a CL31 ceilometerand a single particle mass spectrometer (SPMS) in a mountainous setting. TheSPMS is used to identify the biomass plume based on levoglucosan andpotassium markers. Data from the SPMS are also used to show that thebiomass plume was correlated with nitrate, but not correlated with sulphateor sodium. This study not only provides baseline measurements of biomassburning plume physico-chemical characteristics in western Canada, but alsohighlights the importance of lidar remote sensing methods in theinterpretation of mountaintop chemistry measurements.