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Measurement Flights in the Arctic Polar Vortex

Jülich Coordinates International Campaign to Predict Ozone Depletion

[14. Januar 2010]

Jülich, 15 January 2010: An international measurement campaign began yesterday in the northern Swedish city of Kiruna. The campaign aims to clarify unanswered questions related to polar ozone depletion in the stratosphere. Measurement flights at altitudes of up to 20 kilometres will provide researchers with data for global climate models, which they will then use to make even more accurate predictions of the future development of the ozone layer and to determine the impact on climate. The campaign, which will last several weeks, is part of the EU project "RECONCILE" involving 17 partners from nine countries. RECONCILE is coordinated by scientists from Forschungszentrum Jülich, member of the Helmholtz Association of German Research Centres.

"We know what processes deplete ozone in the stratosphere but we don't know how fast these processes are. This is what we now want to measure with our partners," says RECONCILE coordinator Marc von Hobe from Forschungszentrum Jülich. Every winter, what is known as the polar vortex forms in the Arctic. In this vortex, the air in the stratosphere circulates around the pole and is thus isolated from air masses at lower latitudes. Extremely low temperatures in the polar vortex lead to the formation of polar stratospheric clouds. These in turn accelerate the formation of chlorine radicals, small molecules that deplete ozone, and in extreme cases, lead to the hole in the ozone layer.

Measurement flights with the special Russian aircraft "M55 Geophysica" - one of three aircraft worldwide with which researchers can fly at altitudes of up to 21 kilometres - will now provide the required data. "With our measurement equipment on board, we can observe the processes that lead to ozone depletion and measure how fast they occur at stratospheric temperatures," says von Hobe. "We need this information to understand the interaction between ozone depletion and climate change and to improve global climate models."

The researchers will spend three weeks in both January and March in Kiruna. "Most of the polar stratospheric clouds usually appear in January and the chlorine is activated," explains von Hobe. "In March, we want to see how much ozone has been chemically depleted over the course of the winter and where to and how fast the ozone-deficient air is transported after the polar vortex breaks up at the end of the winter."

Preparing and conducting the measurement flights at ground temperatures of up to minus 40 °C is a unique challenge faced by those involved in the campaign. "For a successful measurement flight, all groups must work together optimally - scientists, pilots, and technicians," says the head of the campaign, Hans Schlage from the German Aerospace Centre (DLR). The scientists also need a little luck, because there are winters where the polar vortex is not particularly pronounced and the temperatures in the stratosphere are too high for polar stratospheric clouds. "But at the moment, it's looking good," says von Hobe. "There is a stable polar vortex and the temperatures over the last three weeks have been low enough for polar stratospheric clouds to form."


The "Arena Arctica" is a special hangar at Kiruna airport and is the base for the measurement campaign. Photo: Forschungszentrum Jülich


The research aircraft "M55 Geophysica" is one of three aircraft worldwide that can fly at altitudes of up to 21 kilometres. Photo: Forschungszentrum Jülich



Dr. Marc von Hobe
tel. +49 2461 61-4620
email: email:

Prof. Dr. Martin Riese
tel. +49 2461 61-2065
email: email:

Press contacts:

Dr. Barbara Schunk
tel. +49 2461 61-8031

Erhard Lachmann
tel. +49 2461 61-1841