Cosmic rays used to track and visualize tropical cyclones offer new perspectives

For the first time, high-energy muon particles created in the atmosphere have allowed researchers to explore the structures of storms in a way that traditional visualization techniques, such as satellite imaging, cannot. The details this new technique provides could help researchers model storms and related weather effects. This could also lead to more accurate early warning systems.

It’s hard not to notice the number of stories in the news of severe storms in different parts of the world, often attributed to climate change. Weather forecasting and early warning systems have always been important, but with increased storm activity it seems especially so these days. A team of researchers, led by Professor Hiroyuki Tanaka of Muographix at the University of Tokyo, is offering the world of meteorology a new way to detect and explore tropical cyclones using a quirk of particle physics that is constantly playing above our heads. .

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

Muography creates X-ray-like images of large objects, including volcanoes, pyramids, bodies of water and now, for the first time, atmospheric weather systems. Special sensors called scintillators are put together to create a grid, a bit like the pixels on your smartphone’s camera sensor. However, these scintillators don’t see optical light, instead seeing particles called muons, which are created in the atmosphere when cosmic rays from deep space collide with the atoms in the air. Muons are special because they can easily pass through matter without scattering as much as other types of particles. But the small amount by which they deviate as they pass through solid, liquid or even gaseous matter can reveal details of their journey between the atmosphere and the sensors. By capturing a large number of muons passing through something, an image of it can be reconstructed.

“We successfully imaged the vertical profile of a cyclone and this revealed density variations 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 see clearly that it had a warm, low-density core that contrasted dramatically with the cold, high-pressure exterior. absolutely no way to capture such data with traditional pressure sensors and photography.”

The detector the researchers used has a 90-degree viewing angle, but Tanaka is considering combining similar sensors to create semicircular and thus omnidirectional observation stations that can be placed along the length of a coastline. These may be able to see cyclones up to 300 kilometers away. While satellites are already tracking these storms, the extra detail provided by muography could improve predictions about 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, not only for larger storm systems, but also for more localized weather conditions.”

The newspaper is published in Scientific Reports.