A five-day international conference included many grace notes from the Atmospheric System Research program
The latest annual conference of the American Geophysical Union (AGU) was its 2023 AGU Fall Meeting (AGU23) in San Francisco, California. Swarmed by 25,000 international attendees, AGU23 was a treasure chest of town halls, plenaries, oral presentations, and poster sessions. The meeting drew a virtual audience as well.
From December 11 to 15, scientists from 100 countries shared research on subjects ranging from ocean depths to outer space.
Of course, the U.S. Department of Energy (DOE) was there, including spotlights on research funded by DOE’s Atmospheric System Research (ASR) program.
Early-Career ASR Work
On the first day, December 11, ASR program manager Jeff Stehr was among four presenters at an AGU23 Town Hall for early-career scientists. The panelists advised on funding sources, proposal writing, building collaborations, and nascent professorships.
As if on cue, that same day, early-career scientists presented posters and delivered talks on their ASR-funded research.
Baylor University postdoctoral researcher Manisha Mehra outlined her work on biogenic volatile organic compounds across Houston, Texas.
Neil Lareau of the University of Nevada, Reno, five years into his teaching career, gave a presentation on orographic flow regimes in the Andes and how they impact cumulus convection.
“More diversity among scientists is really about giving everyone a fair chance. We want the best brains working on complicated problems.”
– Jeff Stehr
In an invited presentation, University of Oklahoma PhD student Francesca Lappin explained her research on the influence of sea breezes on the atmospheric boundary layer over the Houston region.
Later, on December 14, Stehr was passionately part of another Town Hall panel──this one on emerging opportunities at DOE to enable a more diverse scientific community. Among other presenters was Asmeret Asefaw Berhe, director of DOE’s Office of Science.
“More diversity among scientists is really about giving everyone a fair chance,” he says. “We want the best brains working on complicated problems.”
ASR, ARM, and Key Campaigns
Research funded by ASR continued its thread through the five days of AGU23. Such work was on display during talks and posters on several recent ARM field campaigns──in Texas, Colorado, and California.
“ARM,” whose field operations often include smaller, complementary campaigns linked to ASR research, stands for Atmospheric Radiation Measurement, a user facility in the DOE’s Office of Science. ARM has six observatories (three fixed and three mobile), illustrating the diversity of global climate regimes where DOE collects atmospheric data.
In Texas, from October 2021 through September 2022, the TRacking Aerosol Convection interactions ExpeRiment (TRACER) took place around the Houston region, where marine, rural, and urban influences combine to affect convective activity. TRACER data, now under the lens of modelers and other scientists, will help simulate conditions in similarly stormy, urbanized coastal regions across the world.
A TRACER-related poster on ASR-funded work by postdoctoral researcher Zezhen “Jay” Cheng of Pacific Northwest National Laboratory (PNNL) in southeast Washington state reported on a case study of how the chemical composition and mixing state of aerosols change along a vertical gradient.
Data came from instruments strung on an ARM tethered balloon system during a September 2022 flight. Knowing more about such aerosol vertical profiles can help reduce climate model uncertainties.
Mountainous and Marine
In Colorado, the Surface Atmosphere Integrated Field Laboratory (SAIL) campaign collected 21 months of bedrock-to-atmosphere measurements in complex mountainous terrain from September 2021 to June 2023 near Crested Butte. The mission was to investigate planetary boundary layer processes and how they impact mountain hydrology, on which so much of the world relies for fresh water.
A talk by Allison C. Aiken of Los Alamos National Laboratory in New Mexico discussed her ASR-funded work during SAIL on the seasonal regimes of bioaerosols and supermicron particles—those larger than 1 micron in diameter. The presentation included the first high-resolution observations of bioaerosols in mountainous U.S. terrain.
In California, a third presentation on a key ARM field campaign stirring up AGU23 interest (and revealing more ASR research) was the yearlong Eastern Pacific Cloud Aerosol Precipitation Experiment (EPCAPE) in La Jolla, California. EPCAPE, which ends observations in February 2024, is collecting unprecedented four-season data on the properties of coastal marine clouds, including their radiative effects and the role human-made particles play. The ultimate hope is that EPCAPE data will help inform and validate numerical models used to represent marine cloud processes.
Catherine Banach, a PhD student at the University of California Los Angeles, presented her ASR-sponsored work in a poster on the ability of atmospheric particles in coastal marine clouds to produce “bursts” of OH, a hydroxyl radical that is a key atmospheric oxidant.
TRACER Traces
On December 11, there were TRACER-related presentations on uncrewed systems for aerial research, biogenic volatile organic compounds (BVOCs) across Houston, and the chemistry of secondary organic aerosols created when BVOCs oxidize.
ASR-funded assistant project scientist Lindsay Yee of the University of California Berkeley outlined a case study using mass spectrometry to better identify the chemical composition of unknown biogenic secondary organic aerosols captured in air samples. Normally, she says, 80% of the field-observed spectra of such aerosols remain unidentified.
The main set of TRACER-related oral presentations came on December 14. They included ASR-funded research related to marine and continental aerosols, trace gas pollutants, the characteristics of shallow convection, boundary-layer evolution in an urban coastal environment, and the variability of convective cell characteristics.
TRACER research highlights were also the stuff of poster sessions.
On December 15, a session of 17 TRACER-related posters featured a “tour” of the campaign’s main events by TRACER principal investigator Michael Jensen of Brookhaven National Laboratory (BNL) in New York. Another poster outlined the characterization of submicron aerosol composition by BNL’s Maria Zawadowicz. A third poster, by Pavlos Kollias of BNL and Stony Brook University, explained the high variability of radar-captured deep convective cores.
Signs of SAIL
SAIL talks went full bore on December 14 with eight rapid-fire presentations. Aiken presented again, this time on her ASR-funded aerosol measurements from ARM’s TBS and surface instruments, including ARM’s Aerosol Observing System.
Other ASR-related talks included those reporting aerosol impacts on the spectral albedo of snow, ice particle characteristics, seasonal snow cover change, and an investigation of a historically large snowfall event in December 2021 during SAIL known as the “Santa Slammer.”
Two other presentations featuring ASR science looked at measuring snow sublimation and the impact of springtime precipitation deficits on streamflow.
The day also featured a SAIL-related poster session.
One of the posters, by SAIL principal investigator Daniel Feldman of Lawrence Berkeley National Laboratory in California, highlighted the campaign’s current analysis phase, much of which depends on ASR funding. Another explained the Sublimation of Snow (SOS) campaign, co-located with SAIL and funded by the National Science Foundation.
Many posters heavily represented ASR-funded work, including reports comparing SAIL radars, surface energy fluxes, streamflow energy, and snow temperature profiles.
EPCAPE Entries
AGU23 also brought attention to EPCAPE, the latest of ARM’s coastal campaigns.
A December 14 poster session featured EPCAPE-related works, including ASR-related investigations of the composition of individual particles, cloud condensation nuclei (CCN) activity, and spectromicroscopic characterizations of CCN.
Collaboration was the message of one EPCAPE poster by Mikael Witte of the Naval Postgraduate School, who discussed atmospheric conditions during the June 2023 Southern California Interactions of Low cloud and Land Aerosol (SCILLA) experiment.
SCILLA collected airborne data on trace gases and aerosols to complement EPCAPE measurements. On five of its 21 research flights, SCILLA sampled plumes of pollution identified in satellite data.
During a session of lightning talks on urban air quality trends and challenges, Nattamon Maneenoi of the Scripps Institution of Oceanography at the University of California San Diego reported on her ongoing investigation of air quality impacts from vehicle emissions during EPCAPE and their influence on aerosol chemical composition.
Arctic Notes
Other moments during AGU23 demonstrated another ASR and ARM research focus: that in many campaigns since the 1990s, ARM has maintained an interest in the Earth’s vulnerable high latitudes.
On December 14, Matthew Shupe of the University of Colorado Boulder convened an oral session on the central Arctic’s coupled system of sea ice, ocean, and atmosphere.
Four of the seven talks drew on data from the Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC), an epically comprehensive 2019─2020 international expedition involving 20 nations. DOE provided the earliest funding, and ARM deployed the campaign’s major atmospheric instruments. Shupe was the principal investigator for the DOE/ARM portion of MOSAiC.
In one of the presentations, Ian Baxter of the University of California Santa Barbara discussed how poleward aerosol transport events—“aerosol atmospheric rivers”—affected the arctic climate system during MOSAiC.
Shupe was also the lead author of an ASR-related poster reporting impacts on cryogenic surface energy budgets by two distinct cloud-driven radiative states in the atmosphere, as observed during MOSAiC. One was radiatively opaque and the other optically thin.
Another such poster, by Colorado State University master’s degree student Camille Mavis, looked at the role of melt ponds in producing ice nucleating particles (INP) of biological origin.
In an invited talk on December 14, INP expert and research scientist Jessie Creamean, also at Colorado State, related another slant on MOSAiC and DOE’s interest in high-latitude oceans. She discussed how hard it is for local arctic aerosols to even get airborne. Impediments include snow, freshwater melt layers, and “lids” of ice.
Stehr, the program manager, reflected warmly on arctic research──and every other kind ASR supports.
“I love going to AGU,” he says. “It’s a great chance to meet members of the community at all levels of their careers, from established PIs to undergraduates, mid-career scientists, and retirees. The great ideas on display at AGU help me see the here-and-now of research, as well as what the future holds.”
# # #Author: Corydon Ireland, Staff Writer, Pacific Northwest National Laboratory
This work was supported by the U.S. Department of Energy’s Office of Science, through the Biological and Environmental Research program as part of the Atmospheric System Research program.