Satellite-derived emissions of carbon monoxide, ammonia, and nitrogen dioxide from the 2016 Horse River wildfire in the Fort McMurray area

• Published in: Atmospheric Chemistry and Physics
• Main Authors: C. Adams, C. A. McLinden, M. W. Shephard, N. Dickson, E. Dammers, J. Chen, P. Makar, K. E. Cady-Pereira, N. Tam, S. K. Kharol, L. N. Lamsal, N. A. Krotkov
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2019
• Subjects: Physics; QC1-999; Chemistry; QD1-999; Fort McMurray; Canada; Horse River; Cris
• Online Access: https://doi.org/10.5194/acp-19-2577-2019; https://doaj.org/article/1860600b82f5469798098e171d0b1828

In May 2016, the Horse River wildfire led to the evacuation of ∼ 88 000 people from Fort McMurray and surrounding areas and consumed ∼ 590 000 ha of land in Northern Alberta and Saskatchewan. Within the plume, satellite instruments measured elevated values of CO, NH 3 , and NO 2 . CO was measured by two Infrared Atmospheric Sounding Interferometers (IASI-A and IASI-B), NH 3 by IASI-A, IASI-B, and the Cross-track Infrared Sounder (CrIS), and NO 2 by the Ozone Monitoring Instrument (OMI). Daily emission rates were calculated from the satellite measurements using fire hotspot information from the Moderate Resolution Imaging Spectroradiometer (MODIS) and wind information from the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 reanalysis, combined with assumptions on lifetimes and the altitude range of the plume. Sensitivity tests were performed and it was found that uncertainties of emission estimates are more sensitive to the plume shape for CO and to the lifetime for NH 3 and NO x . The satellite-derived emission rates were ∼ 50–300 kt d −1 for CO, ∼ 1–7 kt d −1 for NH 3 , and ∼ 0.5–2 kt d −1 for NO x (expressed as NO) during the most active fire periods. The daily satellite-derived emission estimates were found to correlate fairly well ( R ∼0.4 –0.7) with daily output from the ECMWF Global Fire Assimilation System (GFAS) and the Environment and Climate Change Canada (ECCC) FireWork models, with agreement within a factor of 2 for most comparisons. Emission ratios of NH 3 ∕CO , NO x ∕CO , and NO x ∕NH 3 were calculated and compared against enhancement ratios of surface concentrations measured at permanent surface air monitoring stations and by the Alberta Environment and Parks Mobile Air Monitoring Laboratory (MAML). For NH 3 ∕CO , the satellite emission ratios of ∼ 0.02 are within a factor of 2 of the model emission ratios and surface enhancement ratios. For NO x ∕CO satellite-measured emission ratios of ∼0.01 are lower than the modelled emission ratios of 0.033 for GFAS and 0.014 for FireWork, ...