Earlier this summer, Smith & Williamson flew a new variant of the Boomerang Balloon Flight Control System inside of two different thunderstorms in Colorado and Nebraska. Known as the “Storm Balloon,” this new research platform was launched just before and after two storms. It was steered into the weather systems by taking advantage of varying wind directions at different altitudes. By placing weather instruments into severe weather for extended periods of time, researchers hope to improve forecasting capabilities and better understand inner storm dynamics.
Storm Balloon—A remote-controlled balloon platform to collect data from inside of severe weather events
In collaboration with Dr. Steven Businger from the University of Hawai’i, Smith & Williamson designed, built, and operated this new, altitude-controllable latex balloon system for storm research. Funding and launch facilities for this project were provided by the Jonathan Merage Foundation. Jonathan Merage’s experience with severe weather was utilized in determining appropriate launch locations and storms of interest for the two test flights. Future versions of the Storm Balloon, using non-latex envelopes, are slated for long-duration flights into hurricanes to better map important parameters of the storm like water vapor content and storm energy exchanges. This new “Hurricane Balloon” would utilize Dr. Businger’s extensive experience from the NOAA Smart Balloon program and provide new measurement capabilities for severe storm researchers.
The First Storm Balloon Flight
The objective of the first flight was to collect measurements in an afternoon summer thunderstorm on the plains east of the Rocky Mountains at the Jonathan Merage Research Ranch. After launch, the Storm Balloon ascended to an initial float altitude of 2000m above ground level (agl). It was determined from on-board sensors that the winds were moving away from storm at this location and altitude. We commanded a descent to 800m agl to find winds that were in the direction of approaching storm front. Ballast was then released to compensate for rain loading to maintain this altitude. As the Storm Balloon entered the storm front it flew through intense rain and hail. After the storm front passed we dropped ballast to ascend inside storm. The balloon reached an altitude of 5275m msl prior to flight termination.
The hardware was recovered without damage after this 100-minute flight. The landing site was only 7km away from the launch site, even though the balloon system traveled a total of 27km over-the-ground. The figure titled “Trajectory profile of Flight 1” shows the altitude and direction of travel of the Storm Balloon during this first flight. This flight illustrates how winds at different altitudes in the proximity of a severe storm can be used for course steering.
The Second Storm Balloon Flight
The objective of this second flight was to launch the Storm Balloon into a thunderstorm with high vorticity1. Since this flight required finding a more substantial thunderstorm a field deployment was necessary. The first potential storm near Ft. Laramie, Wyoming did not have the necessary vorticity, so a different storm was selected to the northeast. We launched behind this southward traveling storm in the town of Whitney, Nebraska after it had formed over the Black Hills. Later reports indicated that this storm had spawned at least three tornadoes near Alliance, Nebraska.
Erratic winds, heavy rain, and lightning made for a very challenging balloon launch environment. After launch, the Storm Balloon ascended to an initial float altitude of 1500m agl. Terrain updraft effects were observed as the system floated at neutral buoyancy. After the rain stopped, the system started to ascend due to decreased water loading. We terminated the flight shortly thereafter since we still had a long drive back to the Research Ranch. The hardware was recovered in a remote field with no damage after a 61-minute flight that traveled 55km.
Storm Balloon Hardware
- Changed the communication message protocol to be able to support both Iridium SBD and line-of-sight commands & telemetry
- Implemented time division multiple access networking for the line-of-sight communication link
- Incorporated a new humidity sensor for in situ cloud measurements
- Improved the helium vent valve feedback to allow for multi-mode valve operations
- Upgraded redundant flight termination circuits for improved safety during low-altitude flights over land
- Designed a new packed parachute housing to minimize water accumulation in wet weather
- Changed the physical enclosure to a foam enclosure with a water-resistive coating to mitigate water penetration and loading in wet weather
Storm Balloon Summary
As an altitude-controllable, free-drifting instrument platform, the Storm Balloon has unique data-collection capabilities when compared to conventional piloted aircraft and unmanned aerial vehicles. Unlike powered aircraft, these balloons can drift with a storm’s air mass and monitor its evolution over a long duration. Moreover, balloons can fly in conditions at low altitude that would ground many other types of aerial platforms. Future work on the Hurricane Balloon platform intends to increase the flight duration to permit week-long low-altitude flights into severe storms over long distances.