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Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
New Zealand-German collaboration in atmospheric research.
Where unpolluted and polluted air masses alternately leave their mark on the atmosphere: Start of the "goSouth-2" field experiment in New Zealand to investigate the effects of air pollution on cloud formation.
Invercargill (Waihōpai)/Leipzig. When it comes to clouds, the region in the far south of New Zealand (Aotearoa) is unique in the world: it is one of the most pristine, cleanest but yet accessible regions on the planet. An international consortium with participation of the Leibniz Institute for Tropospheric Research (TROPOS) and the University of Leipzig will therefore study the clouds in this region in detail for one and a half years during the "goSouth-2" campaign. Embedded in goSouth-2, the Project ACADIA, funded by the German Research Community, will investigate in particular the influence of small changes in air quality on cloud formation. The remote sensing observations from the ground are an important link between the "HALO-South" aircraft mission of the German research aircraft HALO in September-October 2025 and the expeditions of the German research vessels Sonne and Polarstern planned for 2027/28, all of which will investigate the atmosphere of the Southern Ocean at the edge of Antarctica. New Zealand’s MetService and the University of Canterbury in Christchurch (Ōtautahi) are also significantly involved in the projects.
Clean air in the south as a challenge for climate models
In terms of air pollution and the aerosol particles it contains, the region at the southern tip of New Zealand's South Island is unique in the world: it is one of the most pristine yet accessible regions on the planet. The clouds there are mainly influenced by the sea when air masses from the south move towards New Zealand from Antarctica and the Southern Ocean. There are no major continental sources of emissions such as mineral dust, forest fire smoke or man-made contributions from industry and transport along this path. On the other hand, there are also episodes of dusty and man-made air pollution when air masses move over Australia towards New Zealand or when forest fire smoke from Africa or even South America is transported at high altitudes. It is probably the stark contrasts in air pollution that pose previously unsolved challenges for weather and climate models. The quality of cloud forecasts over the southern hemisphere of the Earth is poorer than for the northern hemisphere. The prevailing clean air with a lack of aerosol particles, which are needed as nuclei for cloud droplets or ice crystals, is suspected to be the cause. "Because measurement data from the southern hemisphere is often lacking, atmospheric models used for New Zealand (called Aotearoa “Land of the long white cloud” in the te Reo Māori the language of the indigenous people of New Zealand) are frequently calibrated with data from other regions, particularly the northern hemisphere, leading to errors that affect important decisions on climate resilience," explains Prof. Adrian McDonald from the University of Canterbury in Christchurch (Ōtautahi). The simulations of clouds in the Southern Ocean region therefore contain too many cloud droplets and ice crystals. This error propagates into precipitation forecasts and the determination of the energy balance of the atmosphere and ocean in this region. The south of New Zealand is the ideal place to investigate the causes of the inaccuracies in the weather and climate forecasts and gain a better understanding of the links between air pollution and the formation of clouds and precipitation.
Seven years of preparation for major measurement campaigns on the edge of the Southern Ocean
Preparations have been underway since 2018 for the major atmospheric research project that will collect detailed data on aerosols, clouds and precipitation in the coming months, which is urgently needed by the global climate modelling community. The campaign is called "goSouth-2" because an initial test campaign called "goSouth" was conducted in 2022 in collaboration with the National Institute of Water and Atmospheric Research (NIWA) in New Zealand. Three containers with remote sensing equipment have been shipped from Leipzig to Invercargill on the other side of the world in April. They contain, among other devices, the mobile aerosol and cloud remote sensing system LACROS from TROPOS and a cloud radar from the University of Leipzig. LACROS, the Leipzig Aerosol and Cloud Remote Observations System, comprises a comprehensive set of radar and lidar measuring devices that use radar and light pulses to determine the distribution of aerosols and clouds above the measurement site. "We scan the distribution and movement of aerosol and cloud particles in the atmosphere above us several times per minute with an accuracy of a few metres. These observations allow us to distinguish between various components, such as ice crystals, cloud droplets or the different types of aerosols. This forms the basis for all subsequent investigations into the interactions between aerosols and clouds," explains Dr Patric Seifert from TROPOS. "Since the radars used also record profiles of precipitation particles, it is also possible to investigate the influence of different air masses on rain formation," says Prof. Heike Kalesse-Los from the University of Leipzig. "Unique to the entire southern hemisphere is the new PollyXT fluorescence lidar, which for the first time allows biological particles such as pollen or forest fire smoke to be distinguished from industrial pollution or volcanic aerosols," emphasises Dr Ronny Engelmann.
Cooperation with New Zealand’s 'MetService'
The TROPOS researchers will be working from the Invercargill Observatory operated by MetService adjacent to Invercargill Airport over the coming months. The meteorological observatory will host an extensive array of technology for the campaign: In addition to the remote sensing equipment comprised within LACROS, three in-situ measuring devices will also be used to investigate the number and size distribution of ground-level aerosols and their suitability to act as nuclei for cloud droplets or ice crystals. The location of the observatory at the airport is ideal for the project. Long-term meteorological ground observations and two radiosonde launches (weather balloons) are already carried out there every day. The cooperation between TROPOS and MetService was agreed in spring 2024, when a delegation from TROPOS and NIWA investigated various possible locations for the "goSouth-2" campaign and ultimately decided on the station in Invercargill. "The weather records and radiosonde measurements taken at our station in Invercargill for decades and the TROPOS instruments complement each other perfectly to improve our understanding of the atmosphere in this region," emphasises MetService’s General Manager Observing Systems Kevin Alder.
Contrasts as the key to understanding the clouds of the south
The location at the southern tip of the South Island is ideal for characterising the pristine air from Antarctica and the Southern Ocean. Nevertheless, the researchers expect air masses from Australia, which are more heavily polluted with aerosol particles, to occur about 25 per cent of the time. "This contrast will allow us to make detailed comparisons, as initial analysis of long-term lidar measurements from Lauder, New Zealand, has already shown," explains Patric Seifert. The aim of "goSouth-2" is to conduct a detailed contrast study of cloud properties in clean Antarctic air compared to clouds in aerosol-polluted Australian air. Such an investigation is key to a better understanding of the possible variability of clouds under changing aerosol conditions. To this end, the team led by Patric Seifert and Heike Kalesse-Los from the University of Leipzig has received funding from the German Research Foundation (DFG) for the "ACADIA" project, which will enable two doctoral students to concentrate solely on the research work required for the project for three years. "For example, we will investigate how cloud droplets and ice particles interact with solar radiation and thus influence the climate in this region. To do this, we will use machine learning approaches to estimate the thermodynamics of the clouds and simulate the solar radiation effects of these clouds over the Southern Ocean so that the clouds there can be better accounted for in climate models in the future," explains Heike Kalesse-Los.
"Our local partners have provided us with a great deal of support in the preparations. Without the teams led by Prof. Adrian McDonald (University of Canterbury) and Dr. Guy Coulson (The Air Quality Collective), the complex logistics of the campaign, such as finding locations and dealing with customs formalities, would not have been possible. We are very happy that, thanks to their help, we can finally get started," reports Patric Seifert. The New Zealand partners are funded by their Ministry of Business, Innovation and Employment (MBIE) to support parts of the "goSouth-2" campaign and use the campaign dataset for their own studies: In March 2025, they received an MBIE Catalyst Strategic Grant to support reference measurements and flight planning for HALO-South, and in June 2025, they received an MBIE Smart Ideas Grant, which will be used to support improved climate forecasts for New Zealand (Aotearoa).
Accompanying ground measurements by the University of Leipzig
In addition to their collaboration in the ACADIA project, researchers from the University of Leipzig will accompany the HALO-South flight campaign with additional measurements at the Tāwhaki National Aerospace Centre, 35km south of the city of Christchurch on the east coast of New Zealand's South Island over the coming months. The LIMRAD94 cloud radar from the University of Leipzig was shipped to New Zealand with the TROPOS containers. The station at Tāwhaki will also be reinforced with equipment from the University of Canterbury in Christchurch, which includes a Doppler lidar, a ceilometer and a micro-rain radar. In addition, several radiosondes will be launched from Tāwhaki on each HALO flight day. The ground measurements at Invercargill Airport and the Tāwhaki National Aerospace Centre are also part of the EU project CleanCloud, which investigates the interactions between aerosols and clouds to improve our understanding of climate dynamics in a constantly changing world. The measurements are also integrated into the work of the Leibniz Science Campus "Smoke and Bioaerosols in Climate Change" (LSC BioSmoke), which is investigating the links between forest fires and climate change. All these projects will also make extensive use of the globe-spanning data set from the ESA satellite EarthCARE which was launched in 2024. The data from this combined lidar and radar station in space is essential for putting the local measurements from New Zealand into context with the conditions in other regions of the world.
Kick-off for intensive cooperation between Germany and New Zealand
The measurements in Invercargill and Tāwhaki are an important component of a network of several research projects investigating the interaction between aerosols and clouds in the region around New Zealand. The measurements will begin in good time before the start of an extensive flight campaign: As part of the "HALO-South" mission of the German research aircraft HALO, researchers led by TROPOS will investigate the interaction of clouds and aerosols over the Southern Ocean starting in September. For 5 weeks, HALO will be available for measurement flights from Christchurch over the oceans of the clean southern hemisphere. The mission in New Zealand is a premiere: never before has a German research aircraft investigated the South Pacific and the adjacent Southern Ocean in this region. A total of 176 flight hours are planned for the HALO-South mission. Around 50 researchers will be on site from the Leibniz Institute for Tropospheric Research (TROPOS), the Leipzig Institute for Meteorology at the University of Leipzig, Johannes Gutenberg University Mainz (JGU), the Goethe University Frankfurt (GUF), the Max Planck Institute for Chemistry (MPIC) in Mainz, the Karlsruhe Institute of Technology (KIT), the Institute of Atmospheric Physics of the German Aerospace Centre (DLR) and the Forschungszentrum Jülich (FZJ).
The HALO-South mission and the ground measurements taken by "goSouth-2" are just the beginning of a series of intensive collaborations in the field of atmospheric research between Germany and New Zealand. To mark the cooperation and the start of research activities, celebrations are planned in Invercargill and Christchurch. On 3 September 2025, a public event will be held at the MetService site in Invercargill to launch the goSouth-2 field measurement campaign. On 10 October 2025, there will be a reception for invited guests as part of HALO-South in Christchurch (Ōtautahi). And on 11 October 2025, the HALO team will take part in Explorers' Day, where renowned national and international scientific organisations present their research to young and old alike. The Antarctic research will continue from 2027 to 2030 as part of the major international research project "Antarctica InSync" with a series of expeditions to Antarctica and the Southern Ocean, which are currently being planned and in which atmospheric research will also play an important role. Tilo Arnhold
Dr Patric Seifert
Research Associate, Department of Remote Sensing of Atmospheric Processes, Leibniz Institute for Tropospheric Research (TROPOS)
Tel. +49-341-2717-7080 (NZ = GMT+12h = 21:00-08:00 GMT/UTC !)
https://www.tropos.de/institut/ueber-uns/mitarbeitende/patric-seifert
and
Prof. Heike Kalesse-Los
Remote Sensing and Arctic Climate System Working Group, Institute of Meteorology, University of Leipzig
Tel. +49-341-97-36650 (NZ = GMT+12h = 21:00-08:00 GMT/UTC !)
https://www.physes.uni-leipzig.de/institut-fuer-meteorologie/forschung/arbeitsgr...
and
Kevin Alder
General Manager, Observing Systems at MetService
Tel: +64 27 570 0720
https://www.metservice.com/
and
Prof. Adrian McDonald
University of Canterbury, School of Physical & Chemical Sciences, Faculty of Science
https://profiles.canterbury.ac.nz/Adrian-McDonald
and
Dr Guy Coulson
The Air Quality Collective
https://www.theairqualitycollective.org/about-us/
or
Tilo Arnhold
Public Relations, TROPOS
Tel. +49-341-2717-7189
http://www.tropos.de/aktuelles/pressemitteilungen/
https://www.tropos.de/en/current-issues/press-releases/details/neuseelaendisch-d...
The measurement station LACROS after its installation on the premises of MetService New Zealand in I ...
Quelle: Patric Seifert, TROPOS
Copyright: Patric Seifert, TROPOS
The green laser beam of the PollyXT lidar system of the LACROS station in the nightly sky of Inverca ...
Quelle: Patric Seifert, TROPOS
Copyright: Patric Seifert, TROPOS
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The measurement station LACROS after its installation on the premises of MetService New Zealand in I ...
Quelle: Patric Seifert, TROPOS
Copyright: Patric Seifert, TROPOS
The green laser beam of the PollyXT lidar system of the LACROS station in the nightly sky of Inverca ...
Quelle: Patric Seifert, TROPOS
Copyright: Patric Seifert, TROPOS
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