Sustained monitoring of the EAC: mass, heat and freshwater transports

Voyage Number

IN2022_V06

Voyage Dates

13 Jul, 2022 to 30 Jul, 2022

Voyage Location

Brisbane to Brisbane

Chief Scientist

Dr Chris Chapman

Institution

IMOS

View the full voyage

Voyage summary

Research voyage to the East Australian Current (EAC) off Brisbane to recover a long-term deep-water mooring array for monitoring of ocean and climate.

The long-term ocean monitoring by the EAC deep-water mooring array, a component of the Integrated Marine Observing System (IMOS), is central to our understanding of the relationship between global ocean and climate variability. The EAC is the complex and highly energetic western boundary current of the South Pacific Ocean.  It is the dominant mechanism for the redistribution of heat and freshwater between the ocean and atmosphere in the Australian region.  

The primary voyage objective is to recover six deep-water moorings in waters off Brisbane from the continental shelf (500 m depth) to abyssal waters (5000 m depth).

There are 3other projects included on this voyage:

• Sub-bottom profiling of SE Queensland Bulge (Dr Helen Bostock, UQ): Collection of opportunistic sub-bottom profiles of the SE Queensland ‘bulge’ area to identify possible future coring sites.
• Argo float deployments (Dr Peter Oke, CSIRO): Two standard Argo floats will be deployed during the voyage as part of the international Argo program.
• Indigenous Time at Sea Scholarship (Dr Ben Arthur, CSIRO): Two Indigenous university students will be on the voyage to gain experience and training in at-sea research operations.

The science team on this voyage will have 25 science participants (and 21 crew) representing four institutions.

COVID-19 Protocols

To safeguard the health and well-being of participants, strict COVID-19 protocols apply to all activities on this voyage. This includes a 7-day quarantine on shore and 3-phase PCR testing of all participants for COVID-19 prior to boarding the vessel.

Voyage outcomes

This voyage supported the long-term monitoring of the East Australian Current (EAC) off eastern Australia through the recovery of an array of six full-depth current meter and property (temperature, salinity and pressure) moorings from the continental slope to the abyssal waters off Brisbane. As a result of this voyage, we have extended the time-series of direct observations of the seasonality variability of the EAC. The voyage also enabled extensively sampling of the interaction between a large scale meso-scale eddy, small scale frontal eddy and the EAC. The preliminary investigation of a potentially super-productive submarine canyon was also undertaken.

This project has increased our understanding of the EAC influences on climate, leading to more reliable forecasts for eastern Australia and coastal communities, and improved management of east coast fisheries. The observations being made will be used by the national and international community to improve our understanding of complexity and variability of the heat and salt transport from the tropics to the Tasman Sea, over a range of temporal and spatial scales.

Furthermore, the voyage also provided important education and training opportunities to help develop and train Australia’s future generation of marine experts. This included at-sea training for two doctoral students and four undergraduate students – including two students in the Indigenous Time at Sea Scholarship offered by CSIRO – from four Australian universities.