Mitsumu Ejiri, leader of the 67th Japanese Antarctic wintering team. (Inside photo ©Sankei by Nobuo Serizawa)
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November 2026 will mark 70 years since Japan's first official Antarctic expedition departed from Harumi, Tokyo. Dr Mitsumu Ejiri, an associate professor at the National Institute of Polar Research and leader of the 67th wintering team, will mark this milestone at Syowa Station in Antarctica as Japan's first female wintering team leader.
Japanese Antarctic research teams are conducting a range of observations aimed at uncovering the mysteries of global warming. Dr Ejiri spoke with The Sankei Shimbun and JAPAN Forward, sharing what inspired her to become a researcher and her mindset for spending more than a year working in extreme cold.
Excerpts of the interview follow.
How will your approach to this expedition differ from the last one?
This is my second time participating in a wintering team, but my role is completely different. Last time, I focused all my energy on my own observations. This time, I won't be conducting my own research.
I spend my days asking myself, "What does it mean to go as the wintering team leader?" For this expedition, I consider my previous experience almost irrelevant.
Preparing for the expedition has made me focus on my role as the team leader. I won't make any grand statements, but my first priority is that everyone returns safely. Beyond that, I want to make sure everyone can feel a true sense of accomplishment while achieving the best possible results safely.
People often say, "The second wintering can be dangerous," because misunderstandings or overconfidence [from the first expedition] can lead to accidents. That's why I keep firmly in mind to treat everything as if it's the first time.
November 2026 marks 70 years since the first expedition, but I don't dwell on it. Antarctic research is ongoing, so it feels more like a milestone than a goal. I want to pass the baton we received from the previous team to the next, just as our predecessors did. I feel a strong sense of responsibility — we cannot let our team be the end [of these expeditions]. Of course, I will also do my best at the 70th-anniversary events in Japan and Antarctica.
What is it like to observe 100 kilometers above earth?
I study airglow, a faint light that appears at roughly the same altitude as auroras, and use laser-equipped instruments to measure the density and temperature of the upper atmosphere.
Around 100 kilometers above Earth, the atmosphere reaches its upper limit — essentially the beginning of outer space. At this boundary, the neutral atmosphere mixes with the ionized atmosphere of space, and we aim to understand how these layers exchange energy and what processes occur there.
Observing at this altitude is extremely challenging. The neutral atmosphere is extremely thin, and the ionized atmosphere is sparse. By comparison, at about 400 kilometers — the orbit of the International Space Station — electron density is higher, radar observations are possible, and humans can stay there. But 100 kilometers is a delicate zone: humans cannot remain there, and only a limited set of instruments can be used.
What was it like seeing the Antarctic sky?
What left the strongest impression on me in Antarctica was the star-filled sky I saw at Syowa Station during wintering. Countless stars were visible, both overhead and along the horizon over the sea ice. In Japan, the horizon is often hazy, but in Antarctica, it's crystal clear, giving you the feeling of being in outer space. And when auroras appear, the sight is simply breathtaking.
What were you like as a student?
I grew up in Shimamoto, Osaka, and lived there until the summer of sixth grade. I was the kind of child who didn't want to go home because I loved playing outside, often ignoring curfews. My days were filled with catching insects in nature and flying kites over rice fields after the harvest. I had lots of friends nearby, so I was almost always with someone.
At that time, I wasn't very good with books. The one book I read often was a library find called I Wonder Why?, which used comics and illustrations to answer scientific questions. Adults can't always answer all the questions children have, but this book gave me the satisfaction of understanding something I was curious about — those "Ah, so that's how it works!" moments. That may have been what set me on the path to becoming a researcher.
When it came time to think about high school and university, I decided to study what I love. I liked science and math in middle school, and physics in high school, so I entered the Department of Physics at the Faculty of Science. During university, I realized I wanted to study physics that was closer to nature. Rather than focusing purely on theory, I wanted to observe, collect data, and analyze it.
How did you first get involved in studying the upper atmosphere?
I consulted a professor in my lab and was introduced to the Solar-Terrestrial Environment Laboratory [now the Institute for Space–Earth Environmental Research] at Nagoya University. That's where I first encountered airglow.
Observing airglow reveals atmospheric gravity waves that are invisible to the naked eye. These waves are oscillations in the atmosphere and play a major role in global circulation.
Through these observations, we can see how the enormous energy that drives atmospheric circulation flows and how it changes with the seasons. Seeing something invisible to the eye appear in observation images was a striking experience — it really hit me how much is happening above the clouds.
What kind of research is Japan conducting in Antarctica?
In recent years, Japan's Antarctic teams have focused on summer observations. One key area is the ocean, where Antarctic ice is melting at a rapid pace. Warm seawater flows beneath the massive ice shelves extending from the continent, accelerating the melting process. We are conducting observations to study this phenomenon off Totten Glacier, about 3,000 km east of Syowa Station.
At the same time, we carry out deep ice drilling at Dome Fuji Observation Base II, located about 1,000 km inland at an altitude of approximately 3,700 meters. This large-scale project extracts ice containing air from a million years ago, hidden beneath Antarctica's thick ice sheet.
Both operations require advanced research ships, snow vehicles, and specialized observation equipment, making them highly challenging projects that only Japan can undertake. Antarctic research aims to examine Earth's past while closely monitoring the impacts of warming in polar regions. Both efforts provide crucial information for understanding the mechanisms behind global warming.
What role does the wintering team play in supporting summer Antarctic expeditions?
Careful preparation is essential for successful summer observations, and the wintering team sets the stage. Dome Fuji Observation Base II is not easy to reach. To maximize observation time during the short Antarctic summer, summer team members fly to a base near Syowa Station and then travel about 1,000 km inland by snow vehicle.
The snow vehicles used for this harsh inland journey are maintained in advance. Fuel is transported to the departure base by the wintering team already in Antarctica from the previous year. Wintering team members also prepare food rations for the inland-bound personnel at Syowa Station. Summer projects simply cannot run without the wintering team.
At the same time, wintering team members conduct their own observations. The 67th wintering team, which will operate Syowa Station from February 2026, will also support the 68th summer team later that year. In the past, Antarctic expeditions were considered primarily for wintering, but now research continues seamlessly across both summer and winter seasons.
About Dr Mitsumu Ejiri
Born in 1973 in Kyoto City, Dr Mitsumu Ejiri is an Associate Professor in the Space and Upper Atmosphere Research Group at the National Institute of Polar Research in Tachikawa, Tokyo. She specializes in upper-atmosphere science.
Ejiri graduated from the Faculty of Science at Shizuoka University and completed the doctoral program at the Graduate School of Science, Nagoya University. She then worked at the National Institute for Environmental Studies, Utah State University, and the Research Institute for Sustainable Humanosphere at Kyoto University before taking her current position.
Ejri participated in the 51st Japanese Antarctic Research Expedition summer team and the 58th wintering team, and she will serve as the first female wintering team leader for the 67th expedition. She is scheduled to depart this December and return in March 2027.
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Interview by Nobuo Serizawa
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