Breakout Summary Report

ARM/ASR User and PI Meeting

10 - 13 June 2019

Breakout Description

The breakout was organized by the Aerosol Measurements and Science Group and the Aerosol WG chairs to review progress toward advancing aerosol measurements and discuss remaining issues.

Allison McComiskey opened the session with some history and goals for the session.

Stephen Springston and Janek Uin reported on progress including:

• Addition of O3 at SGP


• ENA site characterization


• Implementation of inlet drying system at SGP


• Addition of APS to AMF1 (for second full-size distribution after SGP)


• PSAP filter migration


• Ongoing work for ACSM quality assessment and harmonized size distributions


• Possible modes for HTDMA: Kappa mode, extending dry size cut range, ambient size (“SMPS mode”) scans


• Plans for aerosol lidar upgrade


• Plans for filter sampling including IMPROVE station at SGP and on tethered balloon

Jim Smith presented progress on the multi-instrument calibration review whitepaper begun at this meeting last year. Whitepaper will be posted soon for public access. Jim also noted the potential for collaboration with Alfred Wiedensohler to link ARM measurements with EU/WMO/GAW standards.

Nicole Riemer presented results of the survey sent out to Aerosol WG members earlier this year (summary also presented in the Tuesday plenary). Questions asked were:

1. Which ARM data products are you using in your research?


2. If you are not using ARM data products in your research, why not?


3. Are there dat products that you wish ARM could provide, but currently does not?

A few key findings (see Nicole’s presentation for additional information):

• Many responses mention the use of campaign data (43 times). Long-term sites were mentioned less frequently (14 times).


• Most cited products in use:




• Size distributions


• Composition (ACSM)


• Hygroscopicity/CCN concentrations




• Most cited concern for not using ARM data was concern about data quality


• Measurement gaps cited included:




• Size distributions covering a wide range of sizes


• Composition information beyond ACSM


• CCN concentrations at different supersaturations


• Complete SGP ground site (including basic trace gases)


• Vertical profiles

Main Discussion

Jim Mather solicited comments regarding additional needs (following the survey). Didn’t get a lot of new information beyond the survey. Issues raised included:

• ARM aerosol measurements are not as useful as satellite for GCM evaluation; further discussion on how to bridge these scales should be considered


• Summary of critical measurement needs:




• Good (and complete) size distributions


• Hygroscopicity


• Chemical speciation




• Some concerns about data quality – data need to be processed to b (calibration/basic qc) or c (higher-order analysis) products.


• Calibrations could be achieved by bringing instruments back to the lab or traveling standards to the field – ARM must determine what works best for the facility


• There was a call for more peer-reviewed publications on the technical aspects of the measurements and the data quality to provide confidence within the community for data use and science publications


• Suggestion that comprehensive and complex measurements made for short periods of time (IOP mode) might serve the science better than running all measurements continuously


• There is need to study optical closure with microphysics for the vertical profile of aerosol


• Ice nucleation community very interested in supermicron particles


• Would like to see composition analysis pushed to > 10 microns (this would be required to achieve the closure discussed above)


• Would greatly benefit from a best estimate, recommended product, and/or merged product (currently too many datastreams)

Future Plans

Jim S and Nicole are sending out the data usage and needs survey again, this time to scientists at other agencies (NSF and NASA). (The group was invited to suggest other audiences who could provide input.

Jim S and the team leading the calibration white paper will distribute that document for public comment.

With the information collected through this survey and at this meeting, the AMSG will reconvene and begin planning a follow-on to the 2017 workshop. Planning for that workshop has not yet started; however, it is likely to focus on working on strategies to address needs identified at the previous workshop and through subsequent engagement with the aerosol science community, including this breakout.