Breakthrough technology offers a new perspective on cyclones

Tropical storm cyclone

An aerial view of a tropical cyclone.

Cosmic rays used to track and visualize tropical cyclones open the eye of the storm.

For the first time, high-energy muon particles generated in the atmosphere have allowed researchers to examine storm structures in a way that conventional viewing methods, such as satellite imagery, cannot. The level of detail of this new method could help researchers simulate storms and associated weather effects. This could also result in more accurate earlier warning systems.

It’s hard not to notice the numerous reports of severe storms that have occurred in various regions of the globe and which are often attributed to climate change. While weather forecasting and early warning systems have always been important, the current increase in storm activity appears to make them especially important. A team of scientists led by Professor Hiroyuki Tanaka of Muographix at the University of Tokyo has developed a new method to identify and analyze tropical cyclones using a particle physics quirk that occurs continuously overhead.

Cyclone Muograph

The redder areas are warm air at low pressure and the green areas are cooler air at higher pressure. The cyclone in this image is about 15 kilometers high. A line drawing that approximates the shape overlays the display data. Credit: 2022 Hiroyuki KM Tanaka

“You’ve probably seen photographs of cyclones taken from above, showing swirling eddies of clouds. But I doubt you’ve ever seen a cyclone from the side, perhaps as a computer graphic, but never as actual captured sensor data,” Tanaka said. “What we offer the world is the ability to do just that, visualize weather phenomena on large scale like cyclones from a 3D perspective and also in real time.We do this using a technique called muography, which you can think of as an x-ray, but to see really huge things inside.

Muography produces X-ray photographs of large objects such as volcanoes, pyramids, bodies of water and, for the first time, atmospheric weather systems. Scintillators are special sensors that are wired together to form a grid, similar to the pixels on your smartphone’s camera sensor. These scintillators, however, do not see optical light. They see muons, which are produced in the atmosphere when cosmic rays from deep space collide with atoms.

Scintillator sensors

These are the sensors used to detect weakly interacting muon particles. Each scintillator sensor is extremely dense to maximize the chances of a muon interacting with it. Arranged in a grid, the sensors can form a raw image of what the muons have passed through to reach the sensor. Credit: 2022 Hiroyuki KM Tanaka

Muons are special because they pass through matter easily without scattering as much as other types of particles. But the small amount they deflect as they pass through solid, liquid, or even gaseous matter can reveal details of their journey between the atmosphere and sensors. By capturing large numbers of muons passing through something, it is possible to reconstruct a picture of it.

“We have successfully imaged the vertical profile of a cyclone, and this has revealed variations in density that are essential to understanding how cyclones work,” Tanaka said. “The images show cross-sections of the cyclone that passed through Kagoshima prefecture in western Japan. I was surprised to clearly see that it had a hot, low-density core that contrasted dramatically with the cold, high-pressure exterior. There is absolutely no way to capture that data with traditional pressure sensors and photography.”

The detector used by the researchers has a 90-degree viewing angle, but Tanaka plans to combine similar sensors to create hemispherical and therefore omnidirectional observing stations that could be positioned along a coastline. These could potentially see cyclones up to 300 kilometres. While satellites already track these storms, the extra detail afforded by muography could improve predictions of approaching storms.

“One of the next steps for us now will be to refine this technique to detect and visualize storms at different scales,” Tanaka said. “This could mean better modeling and forecasting for not only larger storm systems, but also more local weather patterns.”

Reference: “Atmospheric Muography for Imaging and Monitoring Tropical Cyclones” by Hiroyuki KM Tanaka, Jon Gluyas, Marko Holma, Jari Joutsenvaara, Pasi Kuusiniemi, Giovanni Leone, Domenico Lo Presti, Jun Matsushima, László Oláh, Sara Steigerwald, Lee F. Thompson, Ilya Usoskin, Stepan Poluianov, Dezső Varga and Yusuke Yokota, October 6, 2022, Scientific reports.
DOI: 10.1038/s41598-022-20039-4

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