Observations of Major Carbon Species in Western US Wildfire Smoke Plumes during July and August, 2018

Carbon monoxide, carbon dioxide and methane, the three most abundant carbon species, were measured by in situ methods on the NSF/NCAR C-130 aircraft during the Western wildfire Experiments for Cloud Chemistry, Absorbing Aerosol, and Nitrogen (WE-CAN) field campaign. Airborne observations of Western and Northwestern US fire plumes were undertaken from a base in Boise, ID during July and August, 2018. We will present preliminary carbon monoxide measurements, quantified by an Aerodyne mini-QCL (quantum cascade laser) direct absorbance spectrometer, and carbon dioxide and methane dry mole fractions quantified using a Picarro G2401-m wavelength scanned cavity ringdown spectrometer (WS-CRDS). Particle number concentrations of sizes greater than 100 nm were quantified by a wing-mounted Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) probe by Droplet Measurement Technologies.

Both CO and CO₂ instruments are new offerings in the NSF/NCAR requestable measurements suite. We will present airborne measurement validation results, including laboratory environmental chamber and in-flight tests, as well as in-flight intercomparisons obtained in coordination with the relevant University of Wyoming King Air measurements during the Biomass Burning FLUX (BB-FLUX) experiment.

From WE-CAN and BB-FLUX observations, we will examine the distribution of primary emissions of major carbon species in wildfire smoke plumes produced under a variety of fire and environmental conditions. We will also explore the correlation of carbon monoxide and aerosol number concentration in the sampled smoke plumes.