Feature Article

What Drives a Physicist to Keep Researching
at the Harsh Summit of Mt. Fuji

"Actually, Mt. Fuji was the first proper mountain I ever climbed. I've never even hiked another peak — I really am a researcher dedicated entirely to Mt. Fuji," says Professor Kamogawa with a smile.

At high altitudes like the summit of Mt. Fuji (3,776 m), thin air causes many people to suffer from altitude sickness. But Professor Kamogawa reflects, "Fortunately, my body handles high altitudes just fine — I guess it's a gift from God (laughs)." It's precisely this high-altitude tolerance that has allowed him to continue his research in such harsh conditions for nearly 20 years.

Originally specializing as a physicist in the predictive sciences like Newtonian mechanics — Professor Kamogawa is driven by the belief that "natural disasters should also be predictable through physics." Regardless of category, he continues to pursue the clarity of mechanisms and prediction of lightning, earthquakes, tsunamis, volcanic eruptions, and more.

Charge Into the Thundercloud!
Lightning at Your Feet and Mt. Fuji as "The Earth's Giant Sensor"

Professor Kamogawa's full-fledged entry into summit research came in 2008, when he was asked to measure the static electricity generated by thunderclouds.

The summit of Mt. Fuji is one of the few extreme locations in the world where one can directly enter the base of an approaching thundercloud. As measurements continued in a place where hair stands on end when thunder approaches, his passion grew — and today the site has grown into a globally leading hub for mountain lightning research.

Moreover, Mt. Fuji — standing more than 1,000 meters higher than famous mountain observatories in Switzerland — attracts researchers from around the world as "the Earth's giant sensor," capable of detecting transboundary air pollution from the continent, cosmic rays, and even precursors to earthquakes and volcanic activity.

Related Article: "Mt. Fuji Trivia: The Dangers of Lightning on Mt. Fuji"

Related Article: "Imafuji Thunder Alert (Test Phase): Electric Field Intensity Graph"

Impossible to Measure from the Ground!
Why Must Observations Be Taken at the Summit of Mt. Fuji?

"Why is it that only the summit of Mt. Fuji will do — not another mountain or a ground-level laboratory?" The answer lies in the fact that Mt. Fuji is a "solitary peak" (a mountain with no obstructions around it) soaring to an elevation of 3,776 m.

The air at ground level is heavily influenced by friction with the earth's surface — but at approximately 3,800 m, the summit of Mt. Fuji sits precisely within the high-altitude layer known as the "free atmosphere," liberated from surface friction. Here, transboundary air pollutants such as PM2.5, yellow dust, and microplastics — carried on the wind across national borders from the continent — arrive unfiltered. There is no other location in Japan where raw air, before it descends to the ground, can be directly captured to measure global-scale atmospheric circulation.

Furthermore, the summit holds uniquely miraculous value for earth science as a place where sensors can directly observe the interior of thunderclouds — where drones or aircraft cannot safely remain due to violent winds — and as a fixed ground station for cross-referencing satellite data. The greatest significance of the Certified NPO Fujisan Weather Station Utilization Society's continued observations at the Mt. Fuji Special Regional Meteorological Observatory lies precisely in the ongoing accumulation of this data — data that can only ever be collected at the summit of Mt. Fuji — for the benefit of the Earth.