Laser Research Project Launches to Study Aerosols in New Zealand

An atmospheric research project aimed at studying aerosols officially launched at the MetService site near Invercargill Airport on September 3, 2023. The initiative, known as goSouth-2, is a collaboration between institutions in Germany and New Zealand, including the Meteorological Institute of the University of Leipzig and the Leibniz Institute for Tropospheric Research (TROPOS). New Zealand partners include MetService, the University of Canterbury, and The Air Quality Collective.

At the site, five members of the TROPOS team are preparing the necessary equipment to collect data on how various aerosols affect atmospheric conditions. According to Dr. Patric Seifert, a researcher with TROPOS, aerosols are tiny airborne particles that originate from numerous sources, including the ocean and land. These particles range from salt and dust to pollen and those produced by smoke or volcanic activity.

Aerosols play a critical role in cloud formation, acting as nuclei that allow cloud droplets to coalesce. Dr. Seifert explained, “The less aerosol particles are available, the less cloud particles can form, and vice-versa.” This makes the southern tip of New Zealand, located at the northern edge of the Southern Ocean, an ideal location for studying the interactions between aerosols and clouds.

The unique atmospheric conditions in this region come into play when air masses move in from different sources. Air masses originating from the Antarctic typically result in a cleaner atmosphere, while those arriving from Australia can introduce higher pollution levels. By examining the variations in aerosol content between these two types of air masses, researchers aim to gain a deeper understanding of how clouds react to changes in aerosol concentrations.

Dr. Seifert noted that atmospheric and climate models often struggle to accurately simulate cloud behavior over the Southern Ocean compared to the northern hemisphere. The disparity in aerosol levels between the two hemispheres may contribute to this inconsistency. More extensive data collection has been conducted in the northern hemisphere, which is generally more polluted than its southern counterpart.

The decision to conduct research in Invercargill was influenced by its logistical advantages, including support for operating equipment and accommodating staff. MetService has already established a solid foundation of observational data at the site, which includes long-term records of weather balloon soundings, precipitation data, and solar and thermal radiation measurements.

Although all the data-gathering instruments are land-based, residents in the vicinity may notice a green laser beam in the sky near Invercargill Airport. Dr. Seifert explained that the lidar (light detection and ranging) systems emit laser pulses to investigate aerosol distributions. The fixed beam has been communicated to airport staff to ensure awareness of its presence.

In addition to the lidar systems, researchers will also employ radar technology to monitor clouds and precipitation patterns. The TROPOS team will be stationed at the site for a period of 18 months, while approximately 15 team members in Germany will analyze the collected data.

This initiative follows the successful completion of the goSouth-1 study in 2022, which lasted for one month and took place in Pahia, approximately 50 kilometers from Invercargill. The new project represents a significant advancement in the ongoing effort to understand the complex dynamics of the atmosphere and the vital role of aerosols in climate systems.