High-energy muon particles formed in the atmosphere have enabled scientists to study the structures of storms in a manner that conventional visualization techniques, like satellite imaging, cannot. It is the first time that this has been possible under these circumstances.
Cyclone muograph. The redder areas are low-pressure warm air, and the green areas are higher-pressure cooler air. The cyclone in this image is about 15 kilometers tall. A line drawing approximating the shape overlays the visualization data. Image Credits: ©2022 Hiroyuki KM Tanaka.
Using this new technique, researchers are able to model storms and their associated weather impacts. It can also result in more precise early warning systems. Weather forecasts and early warning systems have always been significant, but with improved storm activity it this has become more critical.
A group of scientists, headed by Professor Hiroyuki Tanaka from Muographix at the University of Tokyo, provides a new way of exploring and detecting tropical cyclones to the world of meteorology using a quirk of particle physics.
You’ve probably seen photographs of cyclones taken from above, showing swirling vortices 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. What we offer the world is the ability to do just this, visualize large-scale weather phenomena like cyclones from a 3D perspective, and in real time too. We do this using a technique called muography, which you can think of like an X-ray, but for seeing inside truly enormous things.
Professor Hiroyuki Tanaka, Muographix, University of Tokyo
Muography forms X-ray-like images of large objects, along with pyramids, volcanoes, waterbodies, and now, for the first time, atmospheric weather systems. Special sensors known as scintillators are combined to create a grid, somewhat like the pixels on the smartphone's camera sensor. These scintillators do not register optical light but rather observe particles known as muons that are formed in the atmosphere while cosmic rays from deep space strike the atoms present in the air.
Muons are unique since they pass through matter effortlessly without scattering as much as other kinds of particles. However, the small quantity they affect as they cross through a solid, liquid, or even gaseous matter, can disclose information about their journey from the atmosphere to the sensors. An image of it can be recreated by catching a huge number of muons crossing through something.
We successfully imaged the vertical profile of a cyclone, and this revealed density variations essential to understanding how cyclones work. The images show cross sections of the cyclone which passed through Kagoshima Prefecture in western Japan. I was surprised to see clearly it had a low-density warm core that contrasted dramatically with the high-pressure cold exterior. There is absolutely no way to capture such data with traditional pressure sensors and photography.
Professor Hiroyuki Tanaka, Muographix, University of Tokyo
The detector used by the scientists has a viewing angle of 90°, but Tanaka envisions integrating identical sensors to form hemispherical and, hence, omnidirectional observation stations that can be positioned beside the coastline length. Potentially, these could see cyclones as distant away as 300 kilometeres. Even though satellites already track these storms, the added data provided by muography can enhance forecasts about forthcoming storms.
“One of the next steps for us now will be to refine this technique in order to detect and visualize storms at different scales. This could mean better modeling and prediction not only for larger storm systems, but more local weather conditions as well,” concluded Tanaka.
Journal Reference:
Tanaka, H. K. M., et al. (2022). Atmospheric Muography for Imaging and Monitoring Tropic Cyclones. Scientific Reports. https://doi.org/10.1038/s41598-022-20039-4.