PNNL

Abstract

The spatial distribution of ambient aerosol particles affects the aerosol-radiation and aerosol-cloud interactions, contributing to the largest uncertainty in global anthropogenic radiative forcing estimations. The boundary layer and lower free troposphere have not been sampled at a sufficient temporal and spatial resolution to fully characterize various atmospheric processes, hampering further understanding of the Earth system. The development of uncrewed aerial systems (UAS) coupled with advanced measurement techniques provides much-needed, mesoscale spatial data of the aerosol microphysical and optical properties around the Southern Great Plains (SGP observatory). Aided by a state-of-the-art 3-dimensional molecular imaging technique enabled by secondary ion mass spectrometry and nanogram-level chemical composition analysis capability via micronebulization aerosol mass spectrometry, we identified the dominant role of the organic-enriched nanometer layers at the surface of aerosol particles in determining aerosol optical and hygroscopic properties profiles above the SGP observatory. Additionally, we provide a framework of observation-simulation interaction for examining how various aerosol hygroscopic properties assumptions inferred from chemical analysis affect cloud formation and radiative forcing in observation-constrained large-eddy simulations. Using observational constraints from the chemical analysis of the aerosol surface coupled with UAS in situ observations produces better agreement between simulation results and Raman lidar retrievals of cloud properties. This framework shows how these advanced capabilities can help significantly improve our current understanding of aerosol-radiation and aerosol-cloud interactions.