Lutjewad Measurement Station

Since the year 2000, the Centre for Isotope Research of the University of Groningen has been maintaining the atmospheric sampling station Lutjewad, next to the dike of the Wadden sea, close to the village of Hornhuizen.

The station exists of a 60 meters tall tower and a laboratory building. The laboratory was renewed in 2013. In the tower we have weather sensors and air inlets at a height of 7, 20, 40, and 60 meters. Through the inlets and a lot of tubing, air is brought to the laboratory. Automatically, (in situ) analyses are done for many atmospheric trace gases, such as the greenhouse gases CO₂, CH₄ and N₂O, and also other gases. Furthermore, air samples are collected in flasks to take to the RUG for further analysis. In the container next to the tower, sophisticated aerosol research is done, while in the scaffold tower two radar systems measure the droplet size of water in clouds.

Greenhouse Gasses

The greenhouse gas carbon dioxide (CO₂) is the most important gas that is measured at Lutjewad. This gas is naturally found in the air, but because of the extensive burning of fossil fuels (natural gas, coal, oil), more CO₂ is released into the atmosphere. Besides the CO₂ concentration, we analyse the isotopes of ¹³CO₂ and ¹⁴CO₂ and all kinds of tracers as well. With these, we obtain information about the origin of the carbon. We also analyse many lesser-known greenhouse gasses, e.g., methane (CH₄), nitrous oxide (N₂O), and, more recently, hydrogen (H₂).

All measurements from our Lutjewad station are linked to analyses from similar stations around the world. This will help us to have a better understanding of our changing climate.

The location in Hornhuizen is ideal for analysing atmospheric air samples because it is far away from large, interfering, carbon dioxide sources such as motorways, factories and cities, and the tower is high enough (60m) to prevent direct interference from local sources and sinks such as the local crops and a farmer’s tractor. When the wind direction is north (west), we measure ‘clean’ air, or European background air. When the wind direction is south (east), we measure air which is influenced by the biosphere and by us (humans).

Aerosols

Aerosol size distribution, chemical composition and cloud condensation nuclei activity are measured inside the small container from a 20m high inlet. Aerosols are small airborne particles arising from, for example, burning fossil fuel and biomass, but they can also have biogenic sources. Beside causing health issues, aerosols also have a significant effect on our climate, because they interact with radiation and influence the forming of clouds and rainfall, which can cool down or warm up our atmosphere. Aerosol research in Lutjewad focusses on origin, concentration, and chemical compounds of the aerosols.

Droplet Size and the Height of Clouds

On top of the 10m scaffold tower is a cloud radar and a microwave radiometer installed in cooperation with the TU Delft. The  microwave radiometer measures temperature and humidity profiles of the atmosphere and the cloud radar measures the cloud and rain droplets, up until a 10 km altitude. In 2024, the KNMI will install a UV depolarization Lidar, including a vertically pointing laser, which will measure backscattering of aerosols as a function of altitude. It can also determine the cloud base height.

Visit related websites

• The European Network (ICOS)
• The European network of aerosols (Tropomi)
• The European network of aerosols (Arctris)
• Ruisdeal observatory | Atmospheric Research Groups in the Netherlands
• TU Delft | Remote Sensing Using Radar Systems
• KNMI
• The RIVM (National Institute for Public Health and the Environment)
• The Global Flyway Network

• Groningen Institute for Evolutionary Life Sciences