The Australian Integrated Marine Observing System (IMOS) is celebrating the first successful deployment and retrieval of a Seaglider in the Southern Ocean.
     The first Southern Ocean Seaglider was successfully launched from the Marine National Facility Research Vessel Southern Surveyor, on the 20th of March at the Southern Ocean Time Series (SOTS) site, some 680 km from Tasmania. The Seaglider was at sea for 76 days before staff from CSIRO retrieved it off the continental shelf near Southport on Friday 4 June.
     This new Seaglider route is funded by the additional funding IMOS received through the Education Investment Fund (EIF) in the 2009 Federal Budget to extend the system out to mid-2013, specifically to enhance monitoring in the Southern Ocean and northern Australian waters.
     The Southern Ocean Time Series (SOTS) site is a multidisciplinary ocean observatory at the Sub-Antarctic Zone, that is collecting sustained observations of the atmospheric surface layer, upper and deep ocean to understand the transfer of heat, moisture, energy and CO2 between the atmosphere and ocean, and improve our knowledge of climate, carbon processes and the role of the ecosystem.
     The Seaglider is one of 17 in the Australian National Facility for Ocean Gliders (ANFOG) fleet, which is operated and managed from the University of Western Australia. The Ocean Gliders are highly specialised equipment and the ANFOG team has built up the capability for using this new technology over the last couple of years.
     ANFOG Facility Leader, Professor Charitha Pattiaratchi said that the completion of this first pilot deployment demonstrated that ocean gliders are a cost-effective platform to sustained monitoring of ocean conditions around Australia particularly in regions which are remote and regularly experiencing harsh ocean conditions – currently there are ocean gliders deployed off south-west Australia and the Coral Sea.

Deploying the Seaglider from the deck of the Southern Surveyor. Photo by Eric Schulz.

     Ocean gliders are autonomous vehicles designed to operate in water depths up to 1000 m. By changing its buoyancy, the Seagliders are able to descend and ascend. They have wings that allow them to move horizontally while profiling across strong currents, which means they are easier to control.
     Seagliders fix their positions via the Global Positioning System (GPS) when they surface and communicate with the onshore laboratory via Iridium satellite, relaying collected data and receiving any new commands from the scientists.
     This first voyage successfully demonstrated the Seagliders capacity in the harsh conditions of the Southern Ocean. Although the Seaglider was taken part way around an eddy, once it was halfway around it was decided to let it continue its loop and then move the glider into a more favourable position before it continued back on its path to Tasmania.
     In the period September 2010 to March 2011, it is expected that Seagliders will be deployed off Tasmania, traverse to the SOTS site and then return. It is expected that at least three Seagliders will be in the water at any given time, with one traversing towards the SOTS site, one at the SOTS site and the other returning to Tasmania.
     The observations from the Seagliders will allow researchers to better understand the currents and ocean parameters such as temperature and salinity in the Southern Ocean that influence the Australian climate and marine ecosystems.
     This is very important as the vast Southern Ocean plays a prominent role in the global climate system, while remaining poorly observed due to its remoteness and harsh conditions and ocean gliders are an ideal platform to observe oceanographic conditions in this region.

The Seaglider track in the Southern Ocean.

     Sustained observation of Australia’s ocean territory is too big a job for a single institution. Through IMOS, the national marine and climate science community is working collaboratively to put the required research infrastructure in place. This Seaglider deployment is an excellent example of scientists working together across a number of institutions including: University of Western Australia, CSIRO Marine Atmospheric and Research, the Bureau of Meteorology and the Antarctic Climate and Ecosystems Cooperative Research Centre at the University of Tasmania.
     IMOS has successfully deployed a range of observing equipment in the osceans around Australia, and is making all of the data freely and openly available through the IMOS Ocean Portal – http://imos.aodn.org.au/webportal/.
     IMOS is supported by the Australian Government, through the National Collaborative Infrastructure Strategy and the Super Science Initiative. It is led by the University of Tasmania on behalf of the Australian marine and climate science community.

For the first time a weather buoy has been deployed in the remote Southern Ocean, moored in water 4.6 km deep, 580 km southwest of Tasmania at 46.75S, 142E. The IMOS Southern Ocean Flux Station (SOFS) was deployed from the Marine National Facility research vessel Southern Surveyor on the 17th of March, and has been relaying back to shore hourly observations of the wind, temperature, humidity, air pressure, sunlight and rain. The data provides insight into the current conditions “down south” as well as helping to build a record in this climatically important region of the world ocean. The real time data plots are available on the IMOS Ocean Portal. The $1M SOFS buoy took 12 months to build in the USA by the Woods Hole Oceanographic Institution, and is operated by the Bureau of Meteorology as part of the Australian Bluewater Observing System Facility.
     As well as aiding weather forecasting, the meteorological observations are used to compute the total heat, mass and momentum fluxes on time scales from diurnal up to annual. While the Southern Ocean plays a significant role in the global climate system, there is a paucity of sustained in situ air-sea flux observations in this harsh and remote region. The high quality observations are a valuable contribution to building the climate record and understanding climate variability.
     For more information contact: Dr Marian McGowen, IMOS Project Officer, 03 6226 7505; 0438 042 744. Visit the Integrated Marine Observing System website at: www.imos.org.au