Facing climate change uncertainty for the Great Barrier Reef


Understanding the role of clouds in the warming and cooling of the planet, and how that role changes in a warming world is one of the biggest uncertainties climate change researchers face.

A key feature in this regard is the influence on cloud properties of cloud condensation nuclei (CCN), the very small atmospheric aerosol particles necessary for the nucleation of every single cloud droplet.

The anthropogenic contribution to CCN is known to be large in some regions; however, the natural processes that regulate CCN over large parts of the globe are less well understood, and particularly in the Great Barrier Reef (GBR).

The production of new aerosol particles from biogenic sources (forests, marine biota, etc.) is a frequent phenomenon capable of affecting aerosol concentrations, and therefore CCN, on both regional and global scales. The biogenic aerosol particles therefore have a major influence on cloud properties and hence climate and the hydrological cycle.

Determining the magnitude and drivers of biogenic aerosol production in different ecosystems is therefore crucial for the future development of climate models.

Scientific objectives

This study will allow us to answer the following fundamental questions:

  • What is the significance of this ecosystem as a natural source of aerosol particles?
  • How strong is this source at the regional level?
  • What is the mechanism of particle production over the GBR?

A supplementary project, titled: Biogeochemical and optical properties of the Coral Sea and Queensland shelf

Voyage objectives

A voyage through the Great Barrier Reef on the RV Investigator, from September to October 2017, will allow us to address four key science questions about the role of atmospheric composition in the GBR region:

  1. Do marine aerosols along the north Queensland coast have a significant signature that is coral-derived?
  2. How does this aerosol change its physicochemical properties, especially its capacity to act as CCN, as winds carry it from the reefs to the north Queensland rainforests?
  3. What is the significance of this ecosystem as a source of aerosol particles and will potential degradation of the reef cause significant variations in particle number being generated over the reef.
  4. Should changes in this aerosol, associated with reef degradation, be taken into account when modelling the radiative climate and rainfall?

Research activities

To address the first 2 voyage objectives, cloud, aerosol and atmospheric composition data, uncontaminated by ship exhaust, will be collected at four dedicated atmospheric measurement stations, where the ship will remain for up to 48(or more) hours oriented into the wind. In addition data will be continuously sampled during the transient parts of the voyage. Special interest will be on the transects through the reef.

Proposed measurement stations

The four proposed measurement stations include:

  • Two stations on the western side of the GBR. These stations will enable us to sample the air masses that have traversed over the reefs and have been enriched by the emissions from the reefs. One of the sites would cover the southern part of the reef and be placed east of the Whitsunday Islands (close to Hydrographers Passage) and the other site would be east of Dunk Island and would cover the middle part of the GBR. The positions of the stations will enable us to capture the process of atmospheric transformation and aging as the air masses traverse long distances over the reefs.
  • One station on the eastern side of the GBR. As the predominant wind direction during the trade wind season is south easterlies this station will enable us to characterise the remote pacific air masses coming towards the GBR. It is preferred the station is upwind of the southern part of the GBR.
  • Optics station in deep water (>200m) east of Heron Island to characterise the sea surface spectral reflectance and in water optical properties including the spectral absorption of optically active constituents in the water.  These observations provide the deep water optical reference spectra to compliment inshore fieldwork undertaken at Heron Island in the previous week.  Optical observations will be used to calibrate the NASA very high resolution airborne hyperspectral sensor PRISM that will be collecting data along selected transects in the GBR throughout September and October 2016.  Given clear skies and good flying conditions every effort will be made to overfly the RV Investigator and collect synchronised data.


RV Investigatorgreat barrier reefair quality researchInternational Laboratory for Air Quality and Health


Other Partners

  • A/Prof Graham Jones, Southern Cross University
  • Dr Alain Protat, BOM
  • Dr Robin Beaman, James Cook University
  • Dr Robyn Schofield, University of Melbourne
  • Dr Hiroshi Tanimoto, NIES Japan
  • Dr Justin Seymour, University of Technology Sydney
  • Dr Mike Harvey, NIWA, New Zealand
  • Lisa Woodward, CSIRO Oceans and Atmosphere
  • Dr Karen Wild Allen, CSIRO Oceans and Atmosphere
  • Dr Melita Keywood, CSIRO Oceans and Atmosphere
  • Sarah Lawson, CSIRO Oceans and Atmosphere
  • Lesley Clementson – CSIRO Oceans and Atmosphere
  • David Blondeau-Patissier – CSIRO Oceans and Atmosphere