Call for FICUS EMSL-ARM Proposals, FY 2027 [Now Closed for LOIs]

EMSL Tethered Balloon–Borne Instruments

EMSL has developed an automated Size and Time-resolved Aerosol Collector (STAC), a Time-Resolved Bulk Aerosol Collector (TBAC), and a 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 particles and VOCs in situ during upcoming ARM campaigns for subsequent "offline" analyses of the physical, chemical, optical, and microphysical properties of particles using multimodal microscopy, spectroscopy, and advanced mass spectrometry techniques at EMSL. For questions about the STAC, TBAC, and TRAVIS systems, please contact Swarup China.

For the offline analysis of VOCs, EMSL acquired a high-throughput thermal desorption gas chromatography coupled to quadrupole time-of-flight mass spectrometry (TD-GC-QTOFMS) instrument. In addition, EMSL will support offline analysis of the vertical profiles of VOCs collected onto sorbent tubes using the TRAVIS system.

STAC is an automated sampler that collects 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 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 particle 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 transmission electron microscopy 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 before flight.

Tethered Balloon Mission Opportunities

ARM has deployed the TBS for years at multiple ARM sites. Applicants may propose to analyze samples collected during past missions or from new planned TBS missions in the 2027 fiscal year (FY).

Samples collected from previous missions are available 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 include samples obtained by STAC and TBAC spanning several seasons. For questions about the STAC, TBAC, or TRAVIS systems, or samples collected from previous campaigns, please contact Swarup China.

Applicants may propose new FY 2027 missions at the Southern Great Plains (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) taking place from June 2026 through September 2027. The proposed location of the TBS deployment will be in Glendale, AZ. If the location is a critical consideration of your proposal, please contact Dari Dexheimer. 

ARM is planning to fly approximately six to eight total TBS missions during FY 2027. A standard mission involves a single tethered balloon carrying baseline ARM instruments in addition to the EMSL STAC, TBAC, and TRAVIS capabilities. Proposed missions are no longer than two weeks in length at the SGP and DUSTIEAIM, and three weeks for missions proposed at the BNF due to existing flight restrictions. Investigators must propose no more than three missions, and requests for multiple missions require strong scientific justification.

Flight operations require the balloon to remain in clear air, 500 feet (~150 m) below the base of nearby clouds, and sustained winds below 12 m/s. TBS flights are generally restricted to a maximum altitude limit of 1.5 km above ground level (AGL) at SGP and BNF and 1.3 km AGL for DUSTIEAIM. An individual flight typically lasts from a few hours to approximately eight hours with varying flight styles. Day and nighttime operations can be proposed for BNF, SGP, and DUSTIEAIM, however nighttime operational approvals have not yet been procured for DUSTIEAIM.     

Note: ARM TBS operations are contingent upon approval from the Federal Aviation Administration. ARM is requesting approval for FY 2027 operations at the SGP and BNF sites and for the DUSTIEAIM campaign. This process can take a considerable amount of time and approvals are not guaranteed.

Proposals for new TBS missions in FY 2027 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 non-baseline 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. Overlapping days may be proposed for the TBS and ArcticShark at BNF or SGP.

For any TBS-related questions, please contact Dari Dexheimer or contact Andy Glen.

ArcticShark Mission Opportunities

In addition to tethered balloon flights, ARM is also expecting to fly its ArcticShark uncrewed aerial system (UAS) in FY2027. Letters of intent will be considered that make use of ArcticShark flights at BNF or SGP.

The ArcticShark provides a baseline set of instruments including aircraft state, meteorological state, and land surface properties along with switchable aerosol payloads. The ArcticShark also carries a version of the STAC aerosol sampler for offline analysis of aerosol particles. The ArcticShark version provides eight filters. The sampler can be programmed for sampling duration or even operated remotely during the flight.

The ArcticShark is a mid-sized UAS with a 22-foot wingspan and a payload capacity of 100 lb. The ArcticShark’s minimum operating altitude is driven by obstructions of the radio signals that control the UAS and are detailed below for each site.  Maximum flight altitude is 17,500 feet above mean sea level (MSL). Actual maximum flight altitude will be governed by the temperature profile encountered (i.e., lower at warmer temperatures).

A typical deployment of the ArcticShark is for approximately 3 weeks and contiguous operations cannot exceed 6 days before a rest day is required.

All flights must maintain legal separation from clouds. Below 10,000 feet MSL, the required separation from clouds is 500 feet below, 1,000 feet above, and 2,000 feet lateral. At or above 10,000 feet MSL, the required separation from clouds is 1,000 feet below, 1,000 feet above, and 1 statute mile lateral.

Flights into clouds or precipitation or between sunset and sunrise are not allowed. The minimum visibility requirement is 5 statute miles.

Maximum flight duration with the current payloads could be as long as six hours, but practically, a maximum flight duration of five hours should be considered (shorter if dictated by weather or airport traffic).

Other operational limitations may have to be imposed, including but not limited to not flying on certain days with high traffic volume.

Overlapping days may be proposed for the TBS and ArcticShark at BNF or SGP. However, during concurrent operations a minimum separation distance of 1 nautical mile must be maintained between the two aerial platforms at all times.

Note: ARM ArcticShark operations are contingent upon approval from the Federal Aviation Administration.  ARM is requesting approval for FY 2027 operations at the SGP and BNF sites. This process can take a considerable amount of time and approvals are not guaranteed.

SGP ArcticShark Operations

The ArcticShark will take off and land from the Blackwell-Tonkawa airport (BKN) [36.74475 N; 97.34918 W]. Flights will be limited to a rectangular operating area bounded by the following four corners: [36.79167 N; 97.32083 W], [36.46667 N; 97.32083 W], [36.46667 N; 97.68917 W], [36.79167 N; -97.68917 W]. Download .kml files. Minimum flight altitudes above ground will be 600 feet AGL along a reasonable number of pre-selected and pre-surveyed routes (1,000 feet otherwise). Maximum flight altitudes are 6,500 feet MSL when outside the blue triangle shown below and 17,500 feet MSL inside the triangle.

View larger version of SGP ArcticShark Operations map.

BNF ArcticShark Operations

The ArcticShark will take off and land from either Cullman Regional Airport (CMD, 34°16’00″N 86°51’30″W) or Posey Field Airport (1M4, 34°16’49″N 87°36’02″W) (see green stars on the map below). Download .kml files. Research flights will be limited to the operating area inside a polygon (solid yellow line on the map) and only east of 87°31’33″W (dashed yellow line).

Typical minimum flight altitudes are 1,500 feet AGL in the operations area. Lower minimum flight altitudes (but not lower than 600 feet AGL) might be possible along a reasonable number of pre-selected and pre-surveyed routes within ~10 nautical miles of the BNF main site (M1 on the map).

During periods when the TBS is operated, ArcticShark flights will be conducted no closer than 2 nautical miles from the BNF M1 site (blue circle on the map).

No sustained operations will be conducted over the Sipsey Wilderness (white line on the map).

View larger version of BNF ArcticShark Operations map.