In this section:
Slocum Glider
• 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 and SARDI to deploy Slocum gliders.
• 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.
• Five month-long Slocum glider missions have been completed across the mouth of Spencer Gulf between July 2008 and April 2010 as part of SAIMOS, with more planned. Typically the glider travels over 500 km performing more than 3000 casts. Both cross and alongshore variability in conductivity, temperature, depth and fluorescence can be measured with the repeated mission path.
• The slocum gliders 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 Slocum glider 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.
• Operating on C cell alkaline batteries, the typical mission duration is around 30 days and they are designed to operate in waters up to 200m.
• 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 Slocum gliders 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 Slocum glider is 1.8 m long and travels at a typical speed of 25-40 m/s.
