Institute of Climate and Energy Systems (ICE)

Stratosphere (ICE-4)

Jülich balloon measurements over the southern hemisphere

15 March 2024

Jülich atmospheric researchers, together with colleagues from the Universidad Technica Federico Santa Maria, Valparaiso, Chile, and the South African weather service SAWS, have measured distributions of trace gases, aerosols and cloud particles up to an altitude of approx. 30 km with high vertical resolution. For this purpose, large weather balloons were equipped with miniaturized sensor packages and launched from an Andean station in Portillo Chile, which is located at an altitude of approx. 3 km, and Beaufort West in South Africa.

Preparing a balloon launch in Beaufort West (South Africa)

A common focus of the measurements in Chile and South Africa was the investigation of the transport of air with high ozone concentrations from the stratosphere into the troposphere. This transport influences the air quality in the atmosphere near the ground. It is very pronounced in the area of the subtropical jet above the Portillo and Beaufort West measuring stations. The simultaneous measurements over both locations also allow conclusions to be drawn about the dependence of the transport on longitude.

In addition to measurements with ozone instruments, a large number of other instruments such as AirCore air samplers, hygrometers and aerosol instruments were used in South Africa, as well as a new instrument developed jointly with the University of Lulea, Sweden, to measure ice clouds. The latter device was able to record high-resolution images of ice crystals in clouds over Africa for the first time. The aerosol devices were used to characterize the particles from the Hunga Tonga Ha'apai volcanic eruption, which have been changing conditions for over two years, particularly in the southern hemispheric stratosphere. The concentrations of ozone, water vapor, methane, carbon dioxide, carbon monoxide, CFCs, aerosols and cloud particles were also precisely measured.

Balloon launch in Portillo in the Chilean Andes

Despite the many challenges that arose in the remote areas of the Chilean Andes and the South African semi-desert, the scientists were able to successfully carry out a total of 26 balloon launches.

Observations of this kind are rare in the southern atmosphere. The new cooperation between Forschungszentrum Jülich, the University of Valparaiso and the South African Weather Service now makes it possible to gain new insights into atmospheric processes in the southern hemisphere. The measurements also provide a basis for comparison with satellite observations with a significantly lower vertical resolution. In the longer term, the measurements will contribute to a better understanding of atmospheric processes and thus to better predictability of air quality, climate and weather.