The Arctic is one of the regions most strongly affected by climate change. In recent decades, the temperature there has risen four times as fast as the global average. The ASCCI measurement campaign coordinated by the Karlsruhe Institute of Technology (KIT) and Goethe University Frankfurt is investigating why the Arctic is warming so much faster than the rest of Earth’s surface and what effects that will have. With measurement flights taking place in the region through early April, the researchers are working to gain a better understanding of the causes and effects of Arctic climate change.
The main focus of the ASCCI (Arctic Springtime Chemistry-Climate Investigations) measurement campaign is on how ozone and water vapor in the upper troposphere and lower stratosphere, i.e. at altitudes between approximately 5 and 15 kilometers, affect (or are affected by) Arctic climate change. In particular, the campaign is investigating the processes that take place in the spring, including the depletion of stratospheric ozone. Processes similar to those of the Antarctic ozone hole take place in the Arctic, especially in years when the stratosphere is cold, and can lead to the destruction of a significant portion of the Arctic ozone layer.
“The stratosphere has warmer and colder winters. That’s completely normal year-to-year variability. But we’re also observing that the increasing amount of greenhouse gases is causing the stratosphere to get colder and colder while temperatures on the ground and in the troposphere keep going up,” said Professor Björn-Martin Sinnhuber from KIT’s Institute of Meteorology and Climate Research, who is coordinating the campaign with Professor Andreas Engel from Goethe University Frankfurt. “The temperatures measured in the Arctic stratosphere this winter were colder than ever. And even though hydrochlorofluorocarbons and other ozone-depleting substances haven’t been produced for decades, it will still be decades before they disappear from the atmosphere completely.” At temperatures below minus 78 degrees Celsius, chlorine compounds undergo chemical changes that make them able to damage and partly destroy the ozone layer. “The measurements we conduct at Goethe University quantify how much ozone-depleting chlorine and bromine is present in the stratosphere. There is still enough to trigger chemical processes in these cold conditions that can lead to human-induced ozone depletion,” Engel said.
At the same time, because of the Hunga Tonga underwater volcanic eruption three years ago, there is still much more water than normal in the stratosphere. During the ASCCI campaign, the scientists also want to investigate how this affects the ozone layer.
HALO research aircraft arriving in Kiruna, Sweden. On the underside of the fuselage is the GLORIA instrument developed and operated by KIT and Forschungszentrum Jülich (photo: Marina Schimpf, DLR).
Better Understanding of Arctic Air Pollutants and Their Effects
In addition, air pollutants are mainly transported into the Arctic in the spring, where they can act as short-lived greenhouse gases. Another objective of the campaign is to gain a better understanding of these processes with targeted measurements. The measurement flights are operated by the German Aerospace Center (DLR) with its HALO aircraft, which is based in the northern Swedish city of Kiruna until April. A key instrument for measurements on board the aircraft is the GLORIA infrared spectrometer jointly developed by researchers from KIT and Forschungszentrum Jülich. GLORIA is one of the few instruments worldwide that can make high-resolution measurements of the vertical distribution of numerous trace substances at high altitudes.
In addition to the campaign’s scientific objectives, the measurements also support preparations for the CAIRT satellite mission intended to determine how Earth’s atmosphere is reacting to climate change. The mission, for which KIT is coordinating the planning, has been selected by the ESA as one of the two remaining candidates for an Earth observation mission called Earth Explorer 11. The final decision will be made in the second half of 2025.
Along with KIT and Goethe University Frankfurt, Forschungszentrum Jülich, the DLR, Heidelberg University, Johannes Gutenberg University Mainz, and the University of Wuppertal are also involved in the ASCCI campaign.
About HALO
HALO (High Altitude and Long Range Research Aircraft) is a joint initiative of German environmental and climate research institutions. HALO receives funding from Germany’s Federal Ministry of Education and Research, the German Research Foundation, the Helmholtz Association, the Max Planck Society, the Leibniz Association, the Free State of Bavaria, KIT, Forschungszentrum Jülich, and the DLR. DLR (German Aerospace Center) owns and operates the aircraft.
More about the KIT Climate and Environment Center
Being “The Research University in the Helmholtz Association”, KIT creates and imparts knowledge for the society and the environment. It is the objective to make significant contributions to the global challenges in the fields of energy, mobility, and information. For this, about 10,000 employees cooperate in a broad range of disciplines in natural sciences, engineering sciences, economics, and the humanities and social sciences. KIT prepares its 22,800 students for responsible tasks in society, industry, and science by offering research-based study programs. Innovation efforts at KIT build a bridge between important scientific findings and their application for the benefit of society, economic prosperity, and the preservation of our natural basis of life. KIT is one of the German universities of excellence.
Flugzeugkampagne Klimawandel in der Arktis_Bild 1
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