Californian forest fire plumes over Southwestern British Columbia: lidar, sunphotometry, and mountaintop chemistry observations 1Department of Geography, the University of British Columbia, Vancouver, British Columbia, Canada
17 Jan 2011
2Science and Technology Branch, Environment Canada, Centre for Atmospheric Research Experiments, Egbert, Ontario, Canada
3Université de Sherbrooke, Sherbrooke, QC, Canada
4Science and Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, Canada
5Atmospheric and Environmental Chemistry, University of Washington-Bothell, Seattle, USA
6NOAA-Earth System Research Laboratory, Global Monitoring Division, Boulder, Colorado, USA
Received: 08 July 2010 – Published in Atmos. Chem. Phys. Discuss.: 02 September 2010 Abstract. Forest fires in Northern California and Oregon were responsible for two
significant regional scale aerosol transport events observed in southern
British Columbia during summer 2008. A combination of ground based
(CORALNet) and satellite (CALIPSO) lidar, sunphotometry and high altitude
chemistry observations permitted unprecedented characterization of forest
fire plume height and mixing as well as description of optical properties
and physicochemistry of the aerosol. In southwestern BC, lidar observations show
the smoke to be mixed through a layer extending to 5–6 km a.g.l. where the
aerosol was confined by an elevated inversion in both cases. Depolarization
ratios for a trans-Pacific dust event (providing a basis for comparison) and
the two smoke events were consistent with observations of dust and smoke
events elsewhere and permit discrimination of aerosol events in the region.
Based on sunphotometry, the Aerosol Optical Thicknesses (AOT) reached maxima
of ~0.7 and ~0.4 for the two events respectively.
Dubovik-retrieval values of reff, f during both the June/July and August
events varied between about 0.13 and 0.15 μm and confirm the dominance
of accumulation mode size particles in the forest fire plumes. Both Whistler
Peak and Mount Bachelor Observatory data show that smoke events are
accompanied by elevated CO and O3 concentrations as well as elevated
K+/SO4 ratios. In addition to documenting the meteorology and
physic-chemical characteristics of two regional scale biomass burning
plumes, this study demonstrates the positive analytical synergies arising
from the suite of measurements now in place in the Pacific Northwest, and
complemented by satellite borne instruments.
Revised: 16 December 2010 – Accepted: 19 December 2010 – Published: 17 January 2011
Citation: McKendry, I., Strawbridge, K., Karumudi, M. L., O'Neill, N., Macdonald, A. M., Leaitch, R., Jaffe, D., Cottle, P., Sharma, S., Sheridan, P., and Ogren, J.: Californian forest fire plumes over Southwestern British Columbia: lidar, sunphotometry, and mountaintop chemistry observations, Atmos. Chem. Phys., 11, 465-477, doi:10.5194/acp-11-465-2011, 2011.