Algorithm investigates the impact of transported aerosol

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Mean percentage change of aerosol number concentration and CCN activation fractions for the three types of long-range transport aerosol events observed at the Eastern North Atlantic by the Atmospheric Radiation Measurement’s Aerosol Observing System in 2017. Image published in Atmospheric Chemistry and Physics and used via Creative Commons license.

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As part of an effort to investigate the impact of long-range transported continental aerosol on the regional aerosol regime in the Eastern North Atlantic, a research team including Los Alamos scientists developed an algorithm that helps identify multiday events of such aerosol transport in the region. The results, described in Atmospheric Chemistry and Physics, analyzed the composition of the aerosol plume transport and point to periodic effects on the Eastern North Atlantic by multiday events of long-range continental aerosol transport. The marine boundary layer also was impacted by the multiday events as a significant source of cloud condensation nuclei (CCN). This is important to constrain because CCN are the aerosols that have the potential to form cloud droplets. Clouds alter surface and atmospheric radiation within the Earth system and continue to contribute large uncertainties within global climate models.

The research applied in situ data collected in 2017 at the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) user facility on Graciosa Island called Eastern North Atlantic (ENA). The measurements were a part of the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) campaign and used the Aerosol Observing System (AOS) data. The ENA is a mostly pristine remote marine environment dominated by marine boundary layer clouds, a setting that offered nine multiday events of long-range transported particles in 2017. The algorithm developed by the team is able to integrate three different types of transported continental events: dust and marine particles, polluted mix particles, and biomass burning particles. The analysis showed that biomass burning aerosol events had the largest impact on CCN activation fractions sampled at ENA.

To better understand aerosol perturbation events on CCN regimes, the study provides key observational constraints that can be used to set parameters based on changes in baseline total particle number concentration to determine different aerosol regimes that impact the region. Those constraints can also parametrize the influence of particles sampled from different size modes within the regimes. The results have the potential to inform improvements and validation in climate models.

Funding and mission

The work was supported by the Atmospheric Radiation Measurement (ARM) user facility and funded by the U.S. Department of Energy (DOE), Office of Science, Office of Biological and Environmental Research. The ARM research facility, a DOE Office of Science user facility sponsored by the Office of Biological and Environmental Research, provided data; data and/or imagery from NASA’s Fire Information for Resource Management System (FIRMS) was also used. This work supports the Global Security mission area and the Science of Signatures capability pillar.

Reference

“Long-range transported continental aerosol in the eastern North Atlantic: three multiday event regimes influence cloud condensation nuclei,” Atmospheric Chemistry and Physics, 23, 4221–4246 (2023); DOI: 10.5194/acp-23-4221-2023. Authors: Francesca Gallo, Allison C. Aiken (Los Alamos National Laboratory); Janek Uin, Stephen Springston, Chongai Kuang (Brookhaven National Laboratory); Kevin J. Sanchez, Richard H. Moore (NASA Langley Research Center); Jian Wang (Washington University in St. Louis); Robert Wood (University of Washington), Fan Mei (Pacific Northwest National Laboratory); Connor Flynn (University of Oklahoma); Eduardo B. Azevedo (University of Azores, Portugal).

Technical contact: Allison C. Aiken (EES-14)