Biomass Burning and continental influence on the Arctic (CM-BB)

Principal Participants: Strong, Drummond, Duck, O'Neill, Sica, Walker, Lynham; Stakeholders: Jones, Lin, Paton-Walsh; Canadian Gov't Departments: EC, Canadian Fire Service (CFS) of Natural Resources Canada (NRCan); International Orgs: NDACC, US Forest Service; HQP: PDF + 1 graduate student.

Rationale The Arctic experiences poor air quality due to transport of pollutants from mid-latitudes. However, there remains some debate regarding the relative importance of Europe, Asia, and North America as pollution sources, further complicated by changes in the global distribution of emissions in recent decades. Biomass burning provides an episodic source of radiatively and photochemically active trace gases and particulates, accounting for more than 90% of the black carbon deposited in the Arctic in spring (Hegg et al., 2009), as well as contributing to enhanced atmospheric pollution (Stohl et al., 2007; Warneke et al., 2009). Boreal fires in Siberia, Canada, and Alaska represent a major perturbation to the Arctic atmosphere in summer, affecting the carbon cycle (Preston and Schmidt, 2006), climate (Amiro et al., 2001), air quality (Colarco et al., 2004), and land ecology (Soja et al., 2007). Fire frequency and intensity are strongly sensitive to climate change and may be strengthened in the future; but the sign and magnitude of these effects are highly uncertain and will vary regionally (Intergovernmental Panel on Climate Change (IPCC), 2007). Efforts to characterize fire emissions are challenging due to varying biomass fuel sources and changing emissions through the life cycle of a fire. Recent studies have combined ground-based trace gas and aerosol optical depth measurements to derive emission factors (the amount of a compound released per amount of dry fuel consumed) for biomass burning products (e.g., Paton-Walsh et al., 2010) and to constrain emissions in chemical transport models (Vigouroux et al., 2012).