In this section:
Seaglider
• The Integrated Marine Observing System (IMOS) (a project of the Australian Government's National Collaborative Research Infrastructure
Strategy) is collaborating with researchers at Flinders University, SARDI, the Victorian EPA and Marine and Freshwater Resources Institute (MAFRI) to deploy an underwater ocean glider.
• One three-month mission has been completed off the coast of Portland, Victoria, with more planned for the near future. During its assignment, it completed over 800 dives to 1000 metres providing data for the shelf slope and sub-tropical convergence zone along the south-eastern section of the Bonney Coast.
• The Australian National Facility for Ocean Gliders (ANFOG) is located at the University of Western Australia and provides access to the technology all around the country.
• The most recent and longest deployment was launched from Tasmania in February on a two-month, 1,500 kilometre survey of the Tasman Sea.
• The Seaglider will be used to determine the nature and magnitude of deep boundary currents between the Eyre Peninsula and western mouth of Bass Strait which at present are largely unknown.
• In addition, the gliders will be used to identify hot spots of exchange that are expected to arise within the many canyons of the region and to trace significant paths of summertime upwelling and wintertime downwelling.
• The Seaglider glides slowly through the ocean propelled by buoyancy control and wing lift to alternately dive and climb along slanting glide paths.
• It dead reckons under water between GPS navigation fixes obtained at the sea surface to glide through a sequence of programmed targets controlled by ANFOG.
• It transmits all data collected and receives commands via satellite data telemetry, exposing its antenna above the sea surface for a few minutes between dive cycles.
• The Seagliders range is sufficient to transit entire ocean basins in missions lasting many months while diving continuously to as deep as 1000m.
• Gliders are routinely launched and recovered manually from small boats with a crew of two, avoiding costly reliance on ships.
• Operation costs a few dollars per kilometre of distance travelled to obtain high-resolution profiles of physical, chemical, and bio-optical variables and estimates of depth-averaged current and surface current.
• All Seagliders come with a conductivity and temperature sensor pair, as well as pressure sensor and altimeter transducer, forming the basic package for measuring seawater properties and stratification.
• In addition, an oxygen sensor, and an optical backscatter and chlorophyll fluorometer are fitted.
• The Seaglider is 1.8 m long (plus a 1m long antenna), can dive to 1000m and travels at a typical speed of 0.5 knots.
• It is expected to be in the water for a period of approximately four months.
