An Overview of NASA Langley Aerosol Research Group (LARGE) Airborne Measurements During the 2019 FIREX-AQ Field Campaign

We present a summary of observations made by the LARGE airborne instrument suite (https://science.larc.nasa.gov/large/) as deployed on the NASA DC-8 aircraft during the recent, Fire Influence on Regional to Global Environments and Air Quality field campaign (FIREX-AQ; https://www.esrl.noaa.gov/csl/projects/firex-aq/). FIREX-AQ consisted of a series of flights sampling both western wildfires and smaller, agricultural burning in the eastern United States that were carried out in July-September, 2019. The LARGE instruments focused on measurements of aerosol concentration and size distribution, CCN concentrations, dry and humidified submicron particle scattering at three wavelengths, and filter-based particle absorption at three wavelengths. One set of particle counters and optical particle sizers was thermally-denuded at 350 degrees Celsius in order to examine the contribution non-volatile aerosol fraction. Finally, quartz filters were collected for offline elemental/organic carbon (EC-OC) analysis. The LARGE instruments, as well as those from collaborating research groups, shared a common isokinetic inlet and bridge dilution system in order to reduce disparities across inlet sampling systems. Carbon dioxide measurements were also made from the aerosol inlet in order to account for possible fire plume heterogeneity across the aircraft fuselage spatial scales. A detailed description of the research flights, LARGE instrument suite, and instrument performance during FIREX-AQ will be discussed.