Call for FICUS Research Proposals with ARM and EMSL, FY 2026

EMSL Balloon-Borne Instruments

EMSL has developed an automated Size and Time-resolved Aerosol Collector (STAC), a Time-Resolved Bulk Aerosol Collector (TBAC), and a new Time-resolved Automated Volatile organIc compounds Sampling (TRAVIS) system to fly as guest instruments on ARM’s Tethered Balloon System (TBS). These instruments will enable researchers to capture aerosols and VOCs in situ during upcoming ARM campaigns for subsequent “offline” analyses of the physical, chemical, optical, and microphysical properties of aerosol particles using multimodal microscopy, spectroscopy, and advanced mass spectrometry techniques at EMSL. For questions about the STAC, TBAC, and TRAVIS systems, please direct questions to Swarup China.

For the offline analysis of VOCs, EMSL recently acquired a high-throughput Thermal Desorption Gas Chromatography coupled to a Quadrupole Time-of-Flight Mass Spectrometry (TD-GC-QTOFMS) instrument. In addition, EMSL will support the offline analysis of the vertical profiles of VOCs collected onto sorbent tubes using the TRAVIS system.

STAC is an automated sampler that collects aerosol particles in the size range of 0.07–2.3 µm. STAC carries 20 filters and is able to switch from one filter to the next in a few seconds but typically integrates over periods on the order of 30 minutes for each filter to obtain a sufficient particle loading for analysis. The STAC platform is integrated with a temperature and relative humidity sensor and a pressure sensor to monitor ambient conditions and may be operated with an optical particle counter to measure the aerosol size distribution and a micro-aethalometer to measure the black carbon mass concentration. The sampler can be programmed with a measurement delay (start time), the number of samples, and the time at each point of sampling. STAC has four stages where size-resolved particles will be collected on multiple substrates for microscopy, spectroscopy, and substrate-based mass spectrometry analysis. The current version of STAC can sample up to 20 different altitudes per flight. STAC has three substrate holders in each stage and can accommodate transmission electron microscopy grids, silicon nitride substrates, or quartz substrates. Typically, two TEM grids (B-film and lacey film) and silicon nitride substrates are placed on each stage.

TBAC collects total aerosols on either quartz or Teflon filters for various bulk chemical analyses.

TRAVIS collects VOC samples at up to six different altitudes for offline analysis at EMSL; the sampling onset time and collection duration are programmed prior to flight.

Tethered Balloon Mission Opportunities

ARM has deployed the TBS for multiple years at multiple ARM sites. Applicants may propose to analyze samples from past missions or from planned TBS missions in the 2026 fiscal year (FY).

In past years, ARM has deployed the TBS at its Southern Great Plains (SGP) site in support of the Surface Atmosphere Integrated Field Laboratory (SAIL) field campaign in the Rocky Mountains in central Colorado and during the Tracking Aerosol Convection Interactions Experiment (TRACER) mobile facility deployment to Houston, TX, during the summer deep convective season. These deployments provided a combination of flights with periods at fixed altitudes and flights that sampled profiles through the boundary layer to altitudes of up to 1.5 km above ground level (AGL).

Applicants may propose to analyze samples from past missions, from ARM’s Bankhead National Forest (BNF) site in northwestern Alabama, or as part of ARM’s Coast-Urban-Rural Atmospheric Gradient Experiment (CoURAGE) campaign in Baltimore, MD. These missions will include samples obtained by STAC and TBAC spanning several seasons.

Applicants may propose new FY 2026 missions for the SGP or BNF site. Proposals will also be considered for the next ARM mobile facility deployment in Phoenix, AZ, the Desert-Urban System Integrated Atmospheric Monsoon (DUSTIEAIM) for the period of April–September 2026. EMSL particle samplers may be requested for any of the FY 2026 missions.

Missions are typically up to two weeks in length, and ARM is planning to fly approximately six to eight total TBS missions during FY 2026. A standard mission involves a single tethered balloon carrying baseline ARM instruments in addition to the STAC, TBAC, and TRAVIS capabilities. Investigators are asked to propose no more than three missions, and requests for multiple missions should be well justified. The balloon must remain in clear air and below the base of nearby clouds. TBS flights are generally restricted to a maximum altitude limit of 1.5 km AGL, and an individual flight typically lasts from a few hours to approximately eight hours with varying flight styles. Only daytime operations may be proposed for BNF and DUSTIEAIM. Daytime or nighttime operations may be proposed at the SGP site.

ARM is seeking permissions from the Federal Aviation Administration (FAA) for FY 2026 operations at the SGP and BNF sites and for the DUSTIEAIM campaign. This process can take a considerable amount of time and is not always successful.

Proposals for new TBS missions in FY 2026 should provide details regarding mission expectations including needed instrumentation, the flight location (SGP, BNF, DUSTIEAIM), the desired season or seasons and time of day, the desired altitude, the number and duration of flights required, the desired meteorological conditions during the flight, whether fixed-altitude flights or profiles would be more appropriate for the applicant’s science goals, and where these factors are important for achieving the applicant’s science goals. Proposals for flights of nonbaseline ARM instruments (including those listed on the ARM TBS webpage) or guest instruments will also be considered but will need to be reviewed in consideration of payload constraints.