Cite this article: Baylon, P., Jaffe, D.A., de Gouw, J. and Warneke, C. (2017). Influence of Long-Range Transport of Siberian Biomass Burning at the Mt. Bachelor Observatory during the Spring of 2015.
Aerosol Air Qual. Res.
17: 2751-2761. https://doi.org/10.4209/aaqr.2017.06.0213
The Siberian 2015 airmass split into two plumes in the eastern Pacific.
Dust was transported with the Siberian smoke, leading to larger Δσsp/ΔCO ratios.
The plume observed at MBO had a higher ΔO3/ΔCO ratio than the aircraft.
The Siberian fires did not lead to ozone exceedances at the surface in North America.
We looked at a Siberian biomass burning (BB) event on Spring 2015 that was observed at Mt. Bachelor Observatory (MBO; 2.8 km a.s.l) and by satellite instruments (MODIS and CALIPSO), and intercepted by the NOAA WP-3D research aircraft during the Shale Oil and Natural Gas Nexus (SONGNEX) campaign. The Siberian airmass split into two plumes in the eastern Pacific. One plume moved eastward and was sampled directly at MBO. The other moved northeast to Alaska and then down to the U.S. Midwest; this second plume was intercepted by the WP-3D aircraft. We find that the ΔO3/ΔCO enhancement ratio at MBO is higher than for the plume intercepted by the aircraft. This is due to the warmer plume observed at MBO which led to thermal decomposition of PAN to NOx. The colder plume observed by the aircraft allowed PAN to be locked up and therefore this led to less ozone production. This is supported by the reactive nitrogen (NOy) measurements from the aircraft, which show that 64% of the NOy is stored as PAN. We also find that the Δσsp/ΔCO enhancement ratios at MBO and on the aircraft were much higher than the ratios for similarly aged Siberian fires that were observed previously in the western U.S. We observe that this is because of dust transport in addition to the fire smoke. Ground-based, satellite, and LiDAR data suggest that the Siberian plume was transported at high elevation, and while it was efficiently transported across the Pacific, there was no significant subsidence over North America. Therefore, this long-range transport event did not lead to air quality impacts at the surface in western North America.