Executive Summary
Accurate tornado forecasting and research depend on both wind and thermodynamic data inside supercell thunderstorms, where Doppler radar alone falls short. Radiosondes—balloon-borne sensors—can sample temperature, humidity, and pressure within dangerous storm cores. Windsond, a miniaturized radiosonde platform, requires much smaller balloons compared to traditional sondes, allowing rapid inflation and deployment of dozens of units. One Windsond receiver can track eight sondes simultaneously (expandable to 126), delivering high-resolution, above-ground thermodynamic profiles. These profiles fill critical gaps in understanding vorticity generation, updraft dynamics, and squall line maintenance. Windsond variants like Swarmsonde have been tested as pseudo-Lagrangian drifters, and the system now contributes to NSF- and NOAA-supported TORUS field campaigns. By combining portable radiosonde launches with real-time data reception, researchers gain unprecedented insights into tornado formation and severe-storm evolution.
Key Learnings
- Doppler radar excels at storm structure but cannot directly measure temperature, humidity, or pressure.
- Thermodynamic profiles are essential to understand tornado genesis and vorticity generation.
- Windsond radiosondes use small balloons for rapid, large-area deployment.
- A single receiver can monitor up to 126 sondes, enabling high-density atmospheric sampling.
- Swarmsonde pseudo-Lagrangian probes have validated multi-sonde tracking in convective storms.
- Windsond plays a key role in NSF/NOAA’s TORUS project for targeted supercell observations.
The Challenge of Tornado Research
Tornadoes—often spawned by supercell thunderstorms—can reach wind speeds up to 300 mph (483 km/h), causing massive destruction. While Doppler radar reveals storm reflectivity and rotation, it cannot capture internal thermodynamic forces like pressure gradients and buoyancy that drive wind accelerations.
Doppler Radar Strengths and Gaps
Doppler radar remains the cornerstone of severe-storm monitoring, mapping precipitation intensity, updrafts, and hail cores. However, radar returns do not provide direct measurements of the temperature, moisture, or pressure fields critical to modeling storm evolution and tornadogenesis.
Radiosondes: Unlocking Storm Interiors
Radiosondes are balloon-launched sensor packages that ascend through storm layers, sampling atmospheric variables. Traditional radiosondes demand large helium balloons, slowing deployment and limiting the number of concurrent launches. Compact sondes for convective storms have been a long-standing need in atmospheric research.
Windsond: Fast, Lightweight Radiosonde Technology
Windsond radiosondes use small weather balloons—up to 20 times smaller than conventional sondes—enabling field teams to preinflate dozens of balloons and launch rapidly as conditions evolve. Key features include:
- Integrated sensors for temperature, humidity, and pressure
- Lightweight construction for minimal balloon lift requirements
- One receiver tracking eight sondes at once, scalable to 126 devices
Swarmsonde Field Trials
In 2017, researchers deployed the Swarmsonde variant—two pseudo-Lagrangian Windsond probes—to capture high-resolution thermodynamic drifts inside supercell updrafts. This experiment demonstrated the system’s ability to monitor multiple sondes in real time, advancing our understanding of vorticity generation and storm maintenance.
Integration with TORUS Project
Windsond now contributes to the NSF- and NOAA-supported TORUS (Targeted Observations using Radar and UAVs in Supercells) campaign. By synchronizing radiosonde launches with radar scans and unmanned aerial vehicle (UAV) observations, TORUS aims to unravel the complex interplay of dynamics and thermodynamics in tornado formation.
Sources
- Korolev, A., & Wang, X. “Aboveground Thermodynamic Observations in Convective Storms from Balloonborne Probes Acting as Pseudo-Lagrangian Drifters,” ResearchGate, 2017.
- National Severe Storms Laboratory (NSSL), “TORUS: Targeted Observations using Radar and UAVs in Supercells,” NOAA, accessed 2023.
About the author
Mattias Wilzén
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