A mobile air chemistry lab called AIRBOX is hitching a ride on Australia’s icebreaker RSV Aurora Australis this summer, to peer into clouds as the ship plies the Southern Ocean.
By shading the earth’s surface and reflecting heat, clouds play a direct role in global warming. Clouds are seeded by tiny particles called aerosols, such as dust, soot or salt crystals.
The AIRBOX campaign, led by the University of Melbourne as part of the Australian Antarctic Program, is investigating the properties of these aerosols.
“We want to know how many aerosols there are, how large they are, how reflective they are, and how much water they can take up,” said project leader Dr Robyn Schofield.
This will provide vital details about the contribution of Southern Ocean clouds to regulating the Earth’s temperature, and remove some of the uncertainty in global climate models.
In the relatively unpolluted air above the Southern Ocean, the major source of aerosols is sea salt from wind shearing the tops off waves.
As a result, the concentrations of aerosols in the polar atmosphere above the Antarctic sea-ice differ from anywhere else.
There are also chemical processes in the ocean and in the sea ice that may influence aerosol concentrations.
The project aims to better understand where the aerosols are coming from that influence the clouds and how they are chemically made.
AIRBOX is a modified shipping container with nine instruments operating from the ship’s upper deck for six months. At least eight other instruments will be added over the summer.
- a mini-LIDAR that uses laser pulses to measure aerosol and cloud profiles up to 10 kilometres up;
- an ozone monitor:
- a trace gas analyser to measure greenhouse gases such as carbon dioxide, nitrous oxide and methane, and
- a spectrometer to measure ultraviolet and visible light and chemicals including bromine monoxide, a naturally-occurring chemical that removes atmospheric mercury produced from industrial sources and power generation.
The use of these instruments is an innovative approach that has not been applied before in this part of the world and will help to improve the reliability of climate models for this region.
Also involved in the AIRBOX (Atmospheric Integrated Research facility for Boundaries and Oxidative Experiments) campaign are the Australian Antarctic Division, University of Tasmania, University of Melbourne, Queensland University of Technology, Macquarie University, University of Wollongong, CSIRO, Monash University and the Australian Nuclear Science and Technology Organisation (ANSTO).