Scientists have embarked on a three-week voyage aboard CSIRO research vessel (RV) Investigator to measure some of the world's cleanest air, in an effort to deepen our understanding of the increasing influence of human activity on the global atmosphere and improve climate modelling.
Located in remote northwest Tasmania, Kennaook/Cape Grim is home to the Kennaook/Cape Grim Baseline Air Pollution Station, which has been monitoring atmospheric composition – the makeup of the air – for nearly 50 years.
The site is renowned for its exceptionally clean air coming off the Southern Ocean, called 'baseline' air as it has had no recent contact with land – making it ideal for measuring the chemical composition of the atmosphere, including changes in greenhouse gas concentrations.
For the first time, scientists aboard RV Investigator will compare air quality from the station with measurements taken up to 1500 km off the coast on the Southern Ocean.
Dr Ruhi Humphries, lead CSIRO scientist, said the aim is to better predict and understand how human activity is affecting the global atmosphere, with a focus on the Southern Ocean which has a strong influence on the Earth's climate.
"The Southern Ocean absorbs a lot of the world's carbon dioxide and heat, so any changes can influence our weather and climate," Dr Humphries said.
"Since the Kennaook/Cape Grim Baseline Air Pollution Station began taking measurements in 1976, carbon dioxide levels have increased by more than 20 per cent, which has implications for future climate change.
"This research aims to measure changes in the atmosphere across the Southern Ocean, focusing on extreme events – like smoke from bushfires – and critical climate components, including changes in trace gases, aerosols and clouds.
"The formation and properties of clouds is influenced by aerosols, and this is particularly true in the pristine conditions of the Southern Ocean.
"This voyage will increase our understanding of how clouds form and behave in the Southern Hemisphere and how much heat is getting to the Earth's surface, and trapped in the climate system.
"This will help improve regional and global climate modelling, air quality modelling, smoke forecasting and Earth System models."
Associate Professor Robyn Schofield from University of Melbourne who is on the voyage said this collaborative research effort will help improve climate monitoring for Australia.
"To collect data from land and at sea, we will be using state-of-the art technology, including a full suite of atmospheric measurements and sampling systems, to improve and validate data quality from both the Kennaook/Cape Grim station and the RV Investigator," Associate Professor Schofield said.
"Many climate models are biased to Northern Hemisphere conditions, however, our research will improve gaps in climate science for the Southern Hemisphere.
"We'll build a comprehensive understanding of the relationship between ocean productivity, aerosol formation, cloud microphysics, cloud dynamics, rainfall properties and surface radiation."
The Kennaook/Cape Grim Baseline Air Pollution Station and the RV Investigator both serve as monitoring stations as part of the World Meteorological Organization's Global Atmosphere Watch, which is an observational network charged with understanding the increasing influence of human activity on the global atmosphere.
Will Ponsonby from the CSIRO Marine National Facility said the technology and systems onboard RV Investigator were specifically designed to enable highly accurate monitoring of the atmosphere wherever the vessel travels.
"RV Investigator is incredibly important in offering Australia's research community a mobile platform to collect atmospheric data from places far remote from land-based monitoring stations, such as from the massive expanses of the Southern Ocean," Mr Ponsonby said.
"The atmospheric monitoring systems on RV Investigator are internationally unique and have been designed and built by CSIRO to deliver the high-quality data needed to better understand and model our changing atmosphere and climate."
Similar atmospheric monitoring systems to those on RV Investigator have been developed and installed by CSIRO in Australia's new icebreaker, RSV Nuyina, to further enhance Australia's ability to collect this globally significant data from our region.
The COAST-K (Clean Ocean Air Sampling upwind of Tasmania – Kennaook) RV Investigator voyage left Hobart on Tuesday 29 April, and will return on 18 May 2025.
