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Abstract. A tethered-balloon system (TBS) has been developed and is beingoperated by Sandia National Laboratories (SNL) on behalf of the U.S.Department of Energy's (DOE) Atmospheric Radiation Measurement (ARM) UserFacility in order to collect in situ atmospheric measurements withinmixed-phase Arctic clouds. Periodic tethered-balloon flights have beenconducted since 2015 within restricted airspace at ARM's Advanced MobileFacility 3 (AMF3) in Oliktok Point, Alaska, as part of the AALCO (AerialAssessment of Liquid in Clouds at Oliktok), ERASMUS (Evaluation of RoutineAtmospheric Sounding Measurements using Unmanned Systems), and POPEYE(Profiling at Oliktok Point to Enhance YOPP Experiments) field campaigns. Thetethered-balloon system uses helium-filled 34 m3 helikites and 79 and104 m3 aerostats to suspend instrumentation that is used to measureaerosol particle size distributions, temperature, horizontal wind, pressure,relative humidity, turbulence, and cloud particle properties and tocalibrate ground-based remote sensing instruments. Supercooled liquid water content (SLWC) sondes using the vibrating-wireprinciple, developed by Anasphere Inc., were operated at Oliktok Point atmultiple altitudes on the TBS within mixed-phase clouds for over 200 h.Sonde-collected SLWC data were compared with liquid water content derivedfrom a microwave radiometer, Ka-band ARM zenith radar, and ceilometer at the AMF3, as well as liquid water content derived from AMF3 radiosonde flights. The in situ data collected by the Anasphere sensors were also compared with data collected simultaneously by an alternative SLWC sensor developed at the University of Reading, UK; both vibrating-wire instruments were typically observed to shed their ice quickly upon exiting the cloud or reaching maximum ice loading. Temperature sensing measurements distributed with fiber optic tethered balloons were also compared with AMF3 radiosonde temperature measurements. Combined, the results indicate that TBS-distributedtemperature sensing and supercooled liquid water measurements are inreasonably good agreement with remote sensing and radiosonde-basedmeasurements of both properties. From these measurements and sensorevaluations, tethered-balloon flights are shown to offer an effective methodof collecting data to inform and constrain numerical models, calibrate andvalidate remote sensing instruments, and characterize the flight environmentof unmanned aircraft, circumventing the difficulties of in-cloud unmanned aircraft flights such as limited flight time and in-flight icing. 

Abstract A multi-agency succession of field campaigns was conducted in southeastern Texas during July 2021 through October 2022 to study the complex interactions of aerosols, clouds and air pollution in the coastal urban environment. As part of the Tracking Aerosol Convection interactions Experiment (TRACER), the TRACER- Air Quality (TAQ) campaign the Experiment of Sea Breeze Convection, Aerosols, Precipitation and Environment (ESCAPE) and the Convective Cloud Urban Boundary Layer Experiment (CUBE), a combination of ground-based supersites and mobile laboratories, shipborne measurements and aircraft-based instrumentation were deployed. These diverse platforms collected high-resolution data to characterize the aerosol microphysics and chemistry, cloud and precipitation micro- and macro-physical properties, environmental thermodynamics and air quality-relevant constituents that are being used in follow-on analysis and modeling activities. We present the overall deployment setups, a summary of the campaign conditions and a sampling of early research results related to: (a) aerosol precursors in the urban environment, (b) influences of local meteorology on air pollution, (c) detailed observations of the sea breeze circulation, (d) retrieved supersaturation in convective updrafts, (e) characterizing the convective updraft lifecycle, (f) variability in lightning characteristics of convective storms and (g) urban influences on surface energy fluxes. The work concludes with discussion of future research activities highlighted by the TRACER model-intercomparison project to explore the representation of aerosol-convective interactions in high-resolution simulations.