Identifying fire plumes in the Arctic with tropospheric FTIR measurements and transport models

Abstract

We investigate Arctic tropospheric composition using ground-based Fourier transform infrared (FTIR) solar absorption spectra, recorded at the Polar Environment Atmospheric Research Laboratory (PEARL, Eureka, Nunavut, Canada, 80 • 05 N, 86 • 42 W) and at Thule (Greenland, 76 • 53 N, −68 • 74 W) from 2008 to 2012. The target species, carbon monoxide (CO), hydrogen cyanide (HCN), ethane (C 2 H 6 ), acetylene (C 2 H 2 ), formic acid (HCOOH), and formaldehyde (H 2 CO) are emitted by biomass burning and can be transported from mid-latitudes to the Arctic.By detecting simultaneous enhancements of three biomass burning tracers (HCN, CO, and C 2 H 6 ), ten and eight fire events are identified at Eureka and Thule, respectively, within the 5-year FTIR time series. Analyses of Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model back-trajectories coupled with Moderate Resolution Imaging Spectroradiometer (MODIS) fire hotspot data, Stochastic Time-Inverted Lagrangian Transport (STILT) model footprints, and Ozone Monitoring Instrument (OMI) UV aerosol index maps, are used to attribute burning source regions and travel time durations of the plumes. By taking into account the effect of aging of the smoke plumes, measured FTIR enhancement ratios were corrected to obtain emission ratios and equivalent emission factors. The means of emission factors for extratropical forest estimated with the two FTIR data sets are 0.40 ± 0.21 g kg −1 for HCN, 1.24 ± 0.71 g kg −1 for C 2 H 6 , 0.34 ± 0.21 g kg −1 for C 2 H 2 , and 2.92 ± 1.30 g kg −1 for HCOOH. The emission factor for CH 3 OH estimated at Eureka is 3.44 ± 1.68 g kg −1 .To improve our knowledge concerning the dynamical and chemical processes associated with Arctic pollution from fires, the two sets of FTIR measurements were compared to the Model for OZone And Related chemical Tracers, version 4 (MOZART-4). Seasonal cycles and day-to-day variabilities were compared to assess the ability of the model to reproduce emissions from fires and their transport. Good agreement in winter confirms that transport is well implemented in the model. For C 2 H 6 , however, the lower wintertime concentration estimated by the model as compared to the FTIR observations highlights an underestimation of its emission. Results show that modeled and measured total columns are correlated (linear correlation coefficient r>0.6 for all gases except for H 2 CO at Eureka and HCOOH at Thule), but suggest a general underestimation of the concentrations in the model for all seven tropospheric species in the high Arctic.

Long‐range transport of NH3, CO, HCN, and C2H6 from the 2014 Canadian Wildfires

“…Large variability of HCN is observed in the summer months at Eureka corresponding to the boreal fire season from May to August [ Macias Fauria and Johnson , ]. Particularly, large fire events in Russia during July 2008 and August 2010 are observed in the time series [ Viatte et al , , ] in addition to the 2014 Northwest Territories fires.…”

“…It has been recently shown that solar absorption spectroscopy using FTIR spectrometers can be used to measure NH 3 total columns [ Dammers et al , ], while biomass burning emissions of carbon monoxide (CO), hydrogen cyanide (HCN) and ethane (C 2 H 6 ) have been previously measured in the Canadian Arctic at Eureka [ Viatte et al , , , ], Australia [ Paton‐Walsh et al , , ], Reunion Island [ Vigouroux et al , ], and Japan [ Zhao et al , ]. The ground‐based FTIR instrument at Eureka provides measurements of NH 3 where satellite observations and in situ data are sparse or nonexistent.…”

Fine Particle Emissions From Tropical Peat Fires Decrease Rapidly With Time Since Ignition

“…For example, in 2015 smoke from peat fires in Indonesia blanketed much of Asia in a persistent plume of pollution throughout September and October (Field et al, ; Huijnen et al, ), contributing to an estimated 100,000 premature deaths due to exposure to fire‐related air pollution (Koplitz et al, ). Due to long‐range transport of these emissions, tropical peatland fires frequently affect large areas of the world (Andreae, ; Edwards et al, ; Viatte et al, ).…”

Unprecedented Atmospheric Ammonia Concentrations Detected in the High Arctic From the 2017 Canadian Wildfires

“…For CO, HCN, and C 2 H 6 , enhanced total columns are periodically observed in May to September at Eureka and Thule, corresponding to the boreal wildfire season (Macias Fauria & Johnson, ). While enhancements of CO, HCN, and C 2 H 6 due to wildfire emissions are observed annually (Viatte et al, ), the only clear case of NH 3 wildfire emissions in the past was observed in July to August 2014 from the NWT wildfires (Lutsch et al, ). However, this does not take into account possible missed events due to instrument downtime or nonclear sky conditions preventing measurements.…”

“…Solar-absorption spectra were processed using the SFIT4 retrieval algorithm (https://wiki.ucar.edu/display/ sfit4/) based on the optimal estimation method (Rodgers & Connor, 2003). Retrievals of CO, HCN, and C 2 H 6 at Eureka and Thule are performed following NDACC Infrared Working Group (IRWG) recommendations as described in Viatte et al (2013Viatte et al ( , 2014Viatte et al ( , 2015 and Lutsch et al (2016) and references therein. For both sites, retrievals of NH 3 were performed following the procedure of Lutsch et al (2016) based on the method of Dammers et al (2015).…”