Uncrewed Vehicle Obtains Aerosols from an Important Atmospheric Zone for Subsequent Characterization Using 3-D Molecular Imaging

The Science 

The spatial distribution of ambient aerosol particles plays a huge role in aerosol–radiation–cloud interactions; however, not enough sampling has been done from the atmospheric boundary layer and lower free troposphere. This leaves large gaps in predictions of anthropogenic changes in the atmospheric energy balance. A multi-institutional team introduces a new approach that merges in situ sampling and measurements using uncrewed aerial systems (UASs) with a cutting-edge three-dimensional chemical imaging analytical method (time of flight secondary ion mass spectrometry) to address this gap in understanding. This combination allows researchers to collect data and samples from the real world for laboratory analysis, which provides new opportunities to advance scientific understanding. It also contributes data needed to make atmospheric models more accurate and reliable. 

The Impact 

By combining UAS in situ measurements and sampling with laboratory chemical analyses, scientists can now gather data from hard-to-sample places while illuminating new aerosol particle structures through offline three-dimensional molecular imaging analysis. The better the data, the better model predictions become. Scientists have demonstrated the value of this new approach, which can be further used to better understand how human-influenced aerosols affect the planet on top of atmospheric changes that occur because of natural processes. In essence, this work helps revolutionize the understanding of the atmosphere and leads to significant advancements in fields such as meteorology and environmental and climate sciences. 

Summary 

Measurements of the vertical distributions of ambient aerosols remain very sparse. Although satellite-based and colocated surface-based remote sensing data provide some detail, their spatial resolution does not provide adequate constraints on model parameterizations of the optical and microphysical properties of aerosols. A multi-institutional team’s new approach and framework shows great potential in constraining process-level model simulations via integrating UAS observational capabilities and advanced chemical analysis. The team leveraged the development of UAS capabilities and advanced measurement techniques to obtain spatial data on the microphysical and optical properties of aerosols around the Atmospheric Radiation Measurement (ARM) user facility’s Southern Great Plains atmospheric observatory in Oklahoma. The UAS flights are used to demonstrate the importance of characterizing aerosols’ chemical composition and surface properties for subsequent use in simulating the impact of microphysical and optical properties on radiative forcing. By integrating advanced chemical information with vertical profiles of the microphysical properties of aerosols, the fidelity of large-eddy simulations of aerosol effects on clouds and the radiation budget can be improved. The team used three-dimensional molecular imaging techniques enabled by secondary ion mass spectrometry and nanogram-level chemical composition analysis to reveal aerosol properties and structural information. Furthermore, the integration of novel chemical analysis techniques from the Environmental Molecular Sciences Laboratory (EMSL), which—like ARM—is a Department of Energy Office of Science user facility, enhances the aerial observational capabilities of ARM, enabling a better process-level understanding of atmospheric aerosols and their effects on climate. Together, these techniques help improve models concerning aerosol–radiation–cloud interactions. 

Contacts 

Zihua Zhu, EMSL, zihua.zhu@pnnl.gov  

Fan Mei, Pacific Northwest National Laboratory, fan.mei@pnnl.gov 

Hailong Wang, Pacific Northwest National Laboratory, hailong.wang@pnnl.gov 

Funding 

This research was supported by the ARM user facility, a DOE Office of Science user facility sponsored by the Biological and Environmental Research (BER) program. A portion of this research was performed on Large-Scale Research and Exploratory Research project awards from EMSL, also a DOE Office of Science user facility sponsored by BER. Additional support was provided by DOE’s Atmospheric System Research (ASR) program under the Integrated Cloud, Land-surface, and Aerosol System Study Science Focus Area and by the ACTIVATE Earth Venture Suborbital-3 (EVS-3) investigation, which is funded by NASA’s Earth Science Division and managed through the Earth System Science Pathfinder Program Office. The simulations were performed using resources available through Research Computing at Pacific Northwest National Laboratory. 

Publication 

F. Mei, et al. “Bridging New Observational Capabilities and Process-Level Simulation: Insights into Aerosol Roles in the Earth System.” Bull. Amer. Meteor. Soc. 3, 105, E709–E724 (2024). [DOI: 10.1175/BAMS-D-23-0110.1]