Laser Research Project Launched to Study Aerosols Near Invercargill

Researchers have launched a new atmospheric study using laser technology at the MetService site close to Invercargill Airport. This initiative, known as the goSouth-2 project, aims to gather critical data on how aerosols—tiny airborne particles—affect cloud formation and overall atmospheric conditions.

The project is a collaborative effort involving prominent institutions from Germany and New Zealand. The German partners include the Meteorological Institute of the University of Leipzig and the Leibniz Institute for Tropospheric Research (TROPOS). New Zealand’s contributions come from MetService, the University of Canterbury, and The Air Quality Collective. A team of five TROPOS staff members is currently setting up equipment at the MetService site, with the official launch scheduled for September 3, 2023.

According to Dr. Patric Seifert, a researcher from TROPOS, aerosols enter the atmosphere from various sources, including sea spray, dust, pollen, and emissions from fires or volcanoes. These particles play a vital role in cloud formation by serving as nuclei for moisture to condense upon. “The less aerosol particles are available, the less cloud particles can form, and vice-versa,” Dr. Seifert explained.

New Zealand’s southern tip, particularly the area at the northern edge of the Southern Ocean, offers a unique environment for studying the interactions between aerosols and clouds. Dr. Seifert noted that the atmosphere in this region can be exceptionally clean when air masses originate from the Antarctic. In contrast, air masses arriving from Australia can carry higher levels of aerosol content. By examining the differences between these air masses, researchers hope to gain insights into how clouds respond to varying levels of aerosols.

Current atmospheric and climate models struggle to accurately simulate cloud behavior over the Southern Ocean compared to the northern hemisphere. The disparities in aerosol levels between the two hemispheres may explain these modeling challenges. The northern hemisphere has more extensive data due to its higher pollution levels, which contrasts with the cleaner atmosphere of the Southern Hemisphere.

Invercargill has been identified as an optimal location for this research due to the logistical support available for operating the equipment and accommodating the research team. MetService has already been conducting significant observations at the site, including ongoing weather balloon soundings, precipitation tracking, and measurements of solar and thermal radiation.

Although all data collection instruments are land-based, residents in the Invercargill area may notice a green laser beam in the sky near the airport. “Our lidar [light detection and ranging] systems emit laser pulses to investigate the aerosols,” Dr. Seifert stated. Airport staff have been informed about the presence of this fixed laser beam.

In addition to lidar, researchers will employ radar systems to detect and analyze clouds and precipitation. The TROPOS team will remain on-site for a duration of 18 months, while an additional group of approximately 15 researchers will focus on data analysis in Germany. This follows the completion of the goSouth-1 project in 2022, which was a month-long study conducted at Pahia, 50 kilometers from Invercargill and utilized fewer resources.

The insights gained from the goSouth-2 project are expected to contribute significantly to improving the understanding of aerosol-cloud interactions, ultimately enhancing climate modeling accuracy in the Southern Hemisphere.