edu.ucar.opensky::articles:21563 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T16:03:50.237274 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7jq13qc Impact of biomass burning plumes on photolysis rates and ozone formation at the Mount Bachelor Observatory 2018-02-27T00:00:00Z publication https://n2t.org/ark:/85065/d7jq13qc https://doi.org/10.1002/2017JD027341 Baylon, P. author Jaffe, D. A. author Hall, Samuel R. author Ullmann, Kirk author Alvarado, M. J. author Lefer, B. L. author UCAR/NCAR - Library publisher In this paper, we examine biomass burning (BB) events at the Mt. Bachelor Observatory (MBO) during the summer of 2015. We explored the photochemical environment in these BB plumes, which remains poorly understood. Because we are interested in understanding the effect of aerosols only (as opposed to the combined effect of aerosols and clouds), we carefully selected three cloud-free days in August and investigate the photochemistry in these plumes. At local midday (solar zenith angle (SZA) = 35 degrees), j(NO2) values were slightly higher (0.2-1.8%) in the smoky days compared to the smoke-free day, presumably due to enhanced scattering by the smoke aerosols. At higher SZA (70 degrees), BB aerosols decrease j(NO2) by 14-21%. We also observe a greater decrease in the actinic flux at 310-350 nm, compared to 360-420 nm, presumably due to absorption in the UV by brown carbon. We compare our measurements with results from the Tropospheric Ultraviolet-Visible v.5.2 model. As expected, we find a good agreement (to within 6%) during cloud-free conditions. Finally, we use the extended Leighton relationship and a photochemical model (Aerosol Simulation Program v.2.1) to estimate midday HO2 and RO2 concentrations and ozone production rates (P(O-3)) in the fire plumes. We observe that Leighton-derived HO2 and RO2 values (49-185 pptv) and instantaneous P(O-3) (2.0-3.6 ppbv/h) are higher than the results from the photochemical model. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2018 American Geophysical Union. None eng geoscientificInformation