Breakout Summary Report

The Aerosol Measurement Science Group (AMSG) is an ARM constituent group that has been formed to enhance communications between ARM and the aerosol science community. The AMSG reports to the ARM Technical Director and its primary purpose is to provide timely input to improve the operational performance, characterization, and science impact of aerosol and trace gas measurements along with the development, processing and delivery of aerosol data products. This breakout will include a series of presentations to communicate the status of activities focused on advancing ARM aerosol measurements and associated data products. Specially, we will provide an update to the community on the 2024 AMSG workshop and resulting report. The focus of this workshop reflects the AMSG’s focus in recent years on building external relationships between ARM and strategic partners that will contribute to the success of ARM to fulfill its mission of improving process representations and predictability in climate models. Sessions held during the workshop ranged from interfacing with external sampling networks and modeling communities to identify core and new aerosol measurements, and provide a clear presentation of measurement uncertainties, calibration protocols, and data products. Updates on the new Center for Aerosol Measurements (CAMS) at Brookhaven National Laboratory will also be presented during this breakout session. The goal of this breakout session is to encourage on-going aerosol community engagement in AMSG.

• AMSG function and membership – Tim Onasch

• First stage of the Absorption Measurement InterComparison Experiment (AMICE) at the SGP Guest Instrument Facility – Connor Flynn

• Artifacts in the Aerosol Size Distribution Measured by the Ultra-High-Sensitivity Aerosol Spectrometer (UHSAS)– Janek Uin

• CAMS Updates: SMPS and CPC Gold-Standard Calibration Capabilities for ARM AOS Instruments- Olga Mayol-Bracero 

• Aerosol Science Update from BNF – Jim Smith

• TRACER/EPCAPE and the AOS sample line integrity checks – Olga Mayol-Bracero

• Update on strategic planning workshop and report – Gannet Hallar and Tim Onasch

• Interactive session to get feedback on themes from strategic planning document - All

• AMSG is looking for new members

• AMICE 1 was successful in collecting useful data on multiple filter-based absorption instruments in attempt to provide a recommendation for PSAP replacement.  AMICE 2 will be conducted later in this fiscal year.

• UHSAS has “artifacts” > 500 nm in recorded size distributions due to uncertainties in refractive indices of measured aerosols. While solution is still to be decided, it was suggested that ARM operate this optical particle counter (OPC) with larger bin sizes that acknowledge these uncertainties – this approach is typical in the aerosol community for OPC operations.

• CAMS (Center for Aerosol Measurement Science) at Brookhaven National Laboratory (BNL) has been initiated and will have infrastructure in place by 5/2025, SGP instrument calibrations will be conducted 9/2025. CAMS is a part of the CARGO-ACT 3 year project, which started 3/2024, and will include a test campaign at BNL ~spring 2027.

• The Bankhead National Forest (BNF) aerosol science presentation by Jim Smith highlighted new particle formation, utilizing size distribution measurements, ACSM chemical measurements, and SO2 and O3 gas phase measurements.  ARM aerosol “nodes” at BNF will be operational by Q4 FY25. The presentation was also an eye-opener for ARM-specific reasons.  Jim listed the explicit data streams he is using in his preliminary analysis and, line-by-line, ARM mentors brought up issues with almost every data stream he had chosen and recommended “better” data streams. In some respects, this was the most effective ARM-related science presentation, as it explicitly stated which data streams were being used for analysis and gave ARM mentors a chance to directly interact with these choices.

• TRACER/EPCAPE – CCN instrument measurement closure studies indicated an issue with the CCN measurements (Nccn). Nccn measurements were affected by a sample line leak during both of these studies – such that the data cannot be used. 

• Update on strategic planning workshop and report – Gannet and Tim presented on the preliminary recommendations from the AMSG Strategic Planning Workshop, which are being written up in the final report, and requested input from the group. Received input from breakout participants related to five different topics from the preliminary recommendations:  (a) strategic partnerships, (b) critical aerosol measurements, (c) integration of measurements with models, (d) platforms and sampling strategies, and (e) data accessibility.

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• Jim Mather will work with Gannet Hallar and Tim Onasch to identify and invite new members to AMSG.

• AMICE 2 needs to be conducted in fiscal year 2025 (i.e., by end of September) and should recommend a PSAP replacement.  Request to interact with European BC project.

• ARM needs to decide how to deal with UHSAS “artifacts” in open and transparent way.

• CAMS should start conducting ARM-related instrument calibrations in fiscal year 2025.

• BNF aerosol science  - ARM should request that users explicitly state which data streams they are using (not just ACSM data, but the actual ARM data archive name of the data).

• TRACER/EPCAPE – ARM needs to conduct inlet checks on all AOS systems before the start of any campaign.  ARM is looking into creating an automatic process for inlet line checks (i.e., overblow of inlet with particle free air).

• Strategic planning workshop - The input from this breakout session will be included in the AMSG Strategic Planning Workshop final report as a separate appendix.

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