The interior of spinning tropical storms may be seen in three dimensions thanks to space debris. Scientists claim in Scientific Reports on October 6 that the inner workings of cyclones over Japan have been revealed by muons produced by cosmic rays that collide with Earth’s upper atmosphere. According to the researchers, the novel imaging strategy could improve our knowledge of storms and provide another tool for weather forecasters.
According to geophysicist Hiroyuki Tanaka of the University of Tokyo, “Cosmic rays are sustainable natural resources that can be exploited everywhere on this world for 24 hours,” so it’s just a matter of using them. Muons provide a window into storms because changes in air pressure and density alter the proportion of particles that survive a storm. Tanaka and colleagues created preliminary 3-D maps of the air density inside the storms by counting how many muons arrived at a detector on the ground in Kagoshima, Japan as cyclones passed by. The strategy allowed the crew to get a close-up view of the low-pressure areas at the center of rotating storm systems.
Similar to electrons but 200 times more heavy, muons can scatter off airborne molecules. Additionally, they are unstable, which means that given enough time, they decompose into electrons and other particles known as neutrinos. The density of air increases with pressure. This in turn raises the possibility that a muon produced by a cosmic ray will be knocked off course while traveling toward a detector or become so slowed that it disintegrates before passing into the atmosphere. According to Tanaka and colleagues, the proportion of muons that make it from the upper atmosphere to the ground reduces by around 2% for every 1% increase in air pressure.
Tanaka has utilized muons produced by cosmic rays in the past to explore inside volcanoes, and he believes that others have employed the particles to research the weather (SN: 4/22/22). However, as far as he is aware, this looks to be the very first time that anyone has performed 3-D muon scans of the interior of a storm. According to Frank Marks, a meteorologist at the National Oceanic and Atmospheric Administration’s Atlantic Oceanographic and Meteorological Laboratory in Miami, who was not involved in the research, “It is an unusual approach.” He doesn’t think that muon imaging will ever take the place of traditional methods of measuring the weather, but he thinks it’s a useful tool for scientists anyway. “[It] would be complementary to the approaches that we already employ in order to offer three-dimensional mapping of the storms using our other traditional observing systems, such as satellites and radar.”