Atmospheric research in Germany will be significantly expanded

ACTRIS is the fundamental European research infrastructure for short-lived atmospheric constituents, expanding Earth system observation and research and providing society with the knowledge to develop sustainable solutions. The acronym ACTRIS stands for Aerosol, Clouds and Trace Gases Research Infrastructure. These short-lived constituents of the atmosphere have a major influence on air quality and climate.

The short-lived climate drivers are usually only in the atmosphere for a few hours to weeks - in contrast to the long-lived greenhouse gases such as carbon dioxide or methane, which remain in the atmosphere for many years to decades. Therefore, much more is known about the effect of the long-lived greenhouse gases compared to the short-lived constituents, although these also have a significant influence on climate. For example, tiny particles suspended in air reflect sunlight and thermal radiation or serve as nuclei for the formation of cloud droplets and ice crystals, which affects precipitation formation. Humans influence the short-lived climate drivers through land use, transport, and energy production, which can have very different consequences: for example, soot particles contribute to warming, while sulphate and nitrate particles have a cooling effect. It is clear that all these factors have an impact on climate and must be taken into account in the predictions. However, the extent of the effects, some of which are very complex, has not yet been sufficiently investigated.

In addition to their impact on climate, short-lived constituents of the atmosphere also have a strong influence on air quality and thus on human health. Suspended particles, colloquially known as particulate matter, and short-lived trace gases such as nitrogen oxides lead to respiratory diseases and reduce life expectancy due to cardiovascular and respiratory diseases.

The impact of human activities on the atmosphere, from a single car to huge forest fires, can only be assessed if measurements are taken continuously and at many points distributed over a large area, because the atmosphere does not know any national borders. This is why the pan-European initiative ACTRIS was adopted to the European Roadmap for Research Infrastructures in 2016. In 2022, ACTRIS will start its long-term work in the legal form of an ERIC (European Research Infrastructure Consortium). With the adoption of the German contribution ACTRIS-D to the National Roadmap for Research Infrastructures in 2019, Germany has committed itself to participating in the European research infrastructure. The Federal Ministry of Education and Research (BMBF) is supporting this initiative as part of the "Research for Sustainability" (FONA) strategy. The BMBF has now begun funding the implementation of ACTRIS-D with an initial total budget of approximately 75 million euros. With these funds, numerous fixed and mobile measurement stations as well as laboratories and simulation chambers will be upgraded or newly constructed over the next five years. A second funding phase for the complete construction of ACTRIS-D is planned for the period 2026 to 2029. In addition, the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) will make an important contribution by providing long-term funding for the operation of service facilities such as the ACTRIS calibration centres.

Background

More than 100 research institutions from 22 countries are participating in ACTRIS. They have set up a network of more than 70 observatories across Europe, which is supplemented by stations in the polar regions, the tropics, and in Asia. In addition, there are 18 simulation chambers and laboratories in Europe in which processes in the atmosphere are simulated in experiments, as well as 17 mobile measurement platforms that can be deployed at different locations. ACTRIS aims to provide effective access to its data, resources, and services to a broad user community to enable high-quality Earth system research. Free and open access will benefit not only Europe as a centre of technology and science, but also environmental authorities and decision-makers, and ultimately citizens across Europe.

ACTRIS-D partner Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI):

The AWI is participating in ACTRIS by building a scanning lidar at the AWIPEV research station on Spitsbergen. A lidar is an optical method for remote measurement. By measuring the time of flight with a pulsed laser, height-resolved profiles of aerosol properties can be measured. This is important because in the polar regions aerosols, which have a cooling effect in the low latitudes, can heat up the atmosphere due to the low solar radiation during the course of the year and the high surface albedo. Therefore, aerosols are an important component in the Arctic climate system, even if their concentration is lower than in Europe.

Aerosols are measured in two different ways in Ny-Alesund, where the AWIPEV station is located. In the in-situ method, outside air containing aerosols is sucked in and the aerosols are deposited on filters from which they can be further investigated (e.g. separation into chemical components or derivation of a size distribution). These in-situ methods are fairly accurate, but are only available on the ground. This is not sufficient for a realistic estimation of the climate impact. These in-situ measurements are carried out by our research partners from Italy, Sweden, Norway and Korea. Furthermore, aerosols are measured by AWI using optical remote sensing, which takes advantage of the fact that aerosols scatter part of the light. Accordingly, height profiles of the aerosols' optical properties are obtained from lidar data.

The two different measurement methods, in-situ and optical remote sensing, are usually not easy to compare. Aerosols can have very different shapes, sizes and chemical compositions. Accordingly, the relationship between the in-situ data and the lidar data is highly complex. The new scanning lidar will offer the possibility to determine the optical properties of aerosols from exactly the same volume of air from which the in-situ measurements are obtained. This will create a database that will allow a systematic comparison between the different instruments. Questions about how the aerosol is mixed vertically in the Arctic boundary layer will also be answered with this new lidar.

Overall, this instrument will bundle and combine aerosol research in Ny-Alesund. If the lidar data on the ground can be calibrated by the in-situ instruments and then a reliable height profile of the aerosol distribution can be derived, the researchers will be able to use it to more accurately record the climate impact of aerosols and test climate models that contain aerosol parameters.

Participating research institutions:

- Leibniz Institute for Tropospheric Research (TROPOS), Leipzig (lead) > https://www.tropos.de/ 
- Alfred Wegener Institute (AWI) - Helmholtz Centre for Polar and Marine Research > https://www.awi.de/ 
- University of Wuppertal (BUW) > https://www.uni-wuppertal.de/ 
- German Meteorological Service (DWD), Offenbach > https://www.dwd.de/ 
- Forschungszentrum Jülich (FZJ) > https://fz-juelich.de/ 
- Goethe University Frankfurt am Main > https://www.uni-frankfurt.de 
- Karlsruhe Institute of Technology (KIT) > https://www.kit.edu /
- Ludwig-Maximilians-Universität Munich (LMU) > https://www.lmu.de/ 
- German Environment Agency (UBA), Dessau > https://www.umweltbundesamt.de/ 
- University of Bremen > https://www.uni-bremen.de 
- University of Cologne > https://www.uni-koeln.de/
 

Links:

ACTRIS - the European Research Infrastructure for the observation of Aerosol, Clouds, and Trace Gases: https://www.actris.eu/
‘Research for Sustainability’ (FONA): https://www.fona.de/en/