Overview:
A decade-long atmospheric research partnership between Palau and Germany is helping scientists better understand some of the world’s most important climate and atmospheric processes. In a recent interview, University of Bremen physicist Justus Notholt highlights how Palau’s unique location in the western Pacific makes it a critical site for studying ozone chemistry, El Niño impacts, and air movement into the stratosphere. Beyond research, the collaboration is also inspiring local students through hands-on physics education at Palau High School and Palau Community College.
The following interview appeared at the University of Bremen (Germaney) online magazine up2date on May 4, 2026.
A physics professor from the University of Bremen travels to the island nation of Palau for research work. During his latest visit, he also taught local students.
© Justus Notholt / University of Bremen
University of Bremen physicist Justus Notholt has already visited Palau six times. Palau, located around 1,000 km east of the Philippines, hosts an atmospheric measurement station that was established 10 years ago jointly by the Alfred Wegener Institute and the University of Bremen as part of the EU project StratoClim. He has just returned from another stay there. While the trip focused on research, it also included physics teaching activities.
Mr. Notholt, why Palau?
The ocean in the western Pacific has the warmest surface temperatures in the world, reaching around 30°C. As a result, the air in this region contains enormous amounts of energy and can rise into the stratosphere — the atmospheric layer between 15 and 50 km altitude. From there, the air slowly moves toward both polar regions, where it descends again.
The composition of the air in the western Pacific therefore plays a major role in determining the global composition of the stratosphere. Measurements of the lower atmosphere in the western Pacific are therefore extremely important for understanding processes in the upper atmosphere across the entire planet.
Do researchers constantly have to travel there? That sounds very demanding.
Most measurements can be operated remotely from Bremen and Potsdam. However, about once a year scientists and technicians from the AWI and the University of Bremen travel to the site to repair and calibrate instruments and to conduct specialized measurement campaigns that cannot be carried out remotely.
Almost all instruments are housed in two air-conditioned containers located on the grounds of the Palau Community College (PCC). Other instruments are operated, for example, in cooperation with the Coral Reef Research Foundation (CRRF). Collaboration with the PCC, the Palau High School, and the CRRF through lectures and guided tours has been very successful.
What exactly are the research questions?
Over recent years, we have focused on three major research topics.
The first concerns how air masses rise from the lower atmosphere into the upper atmosphere. To investigate this, we analyzed lidar measurements (Light Detection and Ranging) taken by the AWI on Palau and interpreted them together with atmospheric model calculations. In lidar measurements, short light pulses are sent into the atmosphere and the reflected signal is measured. This provides information about the altitude and frequency of aerosols and clouds.
A second focus has been the study of ozone chemistry. The air over Palau is extremely clean — perhaps among the cleanest in the world — making it possible to study the daily ozone cycle without interference from anthropogenic reactive gases.
A third and current focus investigates the influence of the weather phenomenon El Niño on the CO₂ balance. Palau lies in a region where El Niño — which globally causes extreme weather events such as droughts and floods — has major impacts on CO₂ concentrations in both the ocean and the atmosphere. This makes Palau an excellent observation site for studying the processes involved.
This time you also taught in schools.
Yes, exactly. I first visited the Palau High School. There we presented and discussed physics experiments that we had previously developed in Bremen as part of our annual science Advent calendar.
In our Advent videos, experiments from mechanics, optics, and electricity are demonstrated and published on the University’s YouTube channel. These German-language videos have become extremely popular and have already received more than four million views.
Some of these experiments have now been incorporated into the physics classes of teacher Noel Ryes at Palau High School. Videos were recorded of all experiments and uploaded to Facebook. Through Facebook, the experiments gained enormous visibility both on Palau and beyond.
As a result, I was invited to present the experiments on the island of Yap at the Yap Catholic High School. There, in cooperation with physics teacher Perfi Angeli Talaid, the experiments were also integrated into physics lessons.
What impression did you get? Was your physics teaching well received?
The students showed tremendous interest. Both high schools maintain a very high academic standard, comparable to a German Gymnasium.
The spread of the experiments through Facebook created major visibility for the activities on Palau and Yap far beyond the schools themselves. I left the materials with the Palau High School, meaning the experiments can continue to be carried out locally by teachers in the future.
Overall, these activities increased the visibility of German research on Palau, especially that of the University of Bremen. Bremen was not entirely unknown in Palau beforehand, however. Several years ago, students from the PCC attended a conference in Bremen organized by the Leibniz Centre for Tropical Marine Research (ZMT).