Characterizing Aerosol Composition According to Precipitation and Air Mass History During the NASA ACTIVATE Field Campaign

Aerosol removal and chemical evolution in different cloud (liquid, mixed-phase, and ice clouds) and precipitation (rain and snow) regimes can vary substantially. In this study, we classify and characterize aerosol composition measurements during ACTIVATE field campaign based on a list of simulated air mass transport history indicators, including accumulated precipitation during transport (APT), source region, and transport timescale and height. ACTIVATE is a NASA Earth-Venture Suborbital-3 mission to robustly characterize aerosol-cloud-meteorology interactions over the western North Atlantic during late winter – early summer using extensive in situ and remote sensing airborne measurements. The mission provides a rich dataset for aerosols affected by clouds and precipitation over the North America and the western North Atlantic. We calculate air mass indicators to characterize air mass history by coupling FLEXPART-GFS Lagrangian Particle Dispersion Model with the MERRA-2 meteorological reanalysis and emission inventories (the Emissions Database for Global Atmospheric Research and the Global Fire Assimilation System). These indicators facilitate the characterization of aerosols affected by certain scavenging processes and understanding of aerosol composition changes during transport. We will examine the statistical relationships of aircraft aerosol measurements with APT and other air mass history indicators during ACTIVATE. Comparing aerosols from a suite of GEOS-Chem model experiments driven by the MERRA-2 reanalysis with the above-classified aircraft measurements will allow a better assessment of overall model biases in below-cloud and in-cloud scavenging processes and thus help reduce model uncertainties in wet scavenging of aerosols.