anfog: australian national facility for ocean gliders

ANFOG: Australian National Facility for Ocean Gliders

CCOG Workshop @ IOS, Sidney, BC

Basics of an Ocean GliderRelated to ARGO floats but with wingsPowered by batteries (C or D cells)Buoyancy engine pumping oil or water into and out of a bladder changes density of vehicle which causes glider to sink or floatWings provide forward momentum motion through the water is a saw tooth patternControl via a rudder or movement of battery pack fore to aft and side to side


Ocean Gliders DescriptionOperation depth ratings 200, 1000, 5000 mDesigned for launch, monitor, recover or launch, forget, recover missions Mission duration 15 days 6 monthsSpeed < 1 kn - typically 0.2-0.5 kntsWeight 50-75 kgs in airMonitored and programmed at surface from control stations located on your desktop. R/T communications at surface via radio link, Iridium, cell, ArgosEasily deployed and recovered from small boats or docks by 1 or 2 personsOperations in all weather


Typical Glider saw tooth motion


Glider Manufacturers3 groups in US building vehicles

Webb Research Slocum Glider, Thermal GliderUofW/APL SeagliderScripps Institute - Spray Glider (now Bluefin)


Slocum Electric GliderManufactured byWebb Research, USA


Slocum Gliders Webb Research


Seaglider UofW / APL


Spray Glider Bluefin Scripps


Spray Glider - Scripps


Development Timeline1989 The Slocum Mission appears in Oceanography1990 Office of Naval Technology (ONT) awards Webb Research Corporation contract for development of Slocum prototype1991 Tests of Slocum prototype and thermal engine in Wakulla Springs FL and Lake Seneca NY1992 First deployment of the ALBAC glider, a shuttle type glider developed at the University of Tokyo in the lab of Tamaki Ura. The ALBAC design uses a drop weight to drive the glider in a single dive cycle between deployment and recovery from ship. It uses a moving internal mass to control pitch and roll.1993 Autonomous Oceanographic Sampling Networks paper appears in Oceanography


Development Timeline1999 Slocum gliders tested at LEO-15 Observatory NJ1999 Autonomous Ocean Sampling Network (AOSN) I conducted in Monterey Bay, CA to make oceanographic surveys. A prototype Spray operates for 11 days. Three Seagliders were also deployed in the bay.2000 By this time all three gliders, Spray, Slocum, and Seaglider, have completed 10 day missions2001 Spray glider makes 280 km section from San Diego2002 Seaglider travels 1000+ km off Washington Coast. Another Seaglider is deployed for month in storms off shelf near Seward Alaska2003 January. Deployment of three Slocum gliders in the Bahamas by WHOI. Trials of prototype thermal Slocum conducted by WRC on same cruise


Development Timeline2003 February. SPAWAR and the Canadian Navy conduct tests in the Gullf of Mexico of 3 Slocum electric gliders.2003 August September. AOSN II conducted in Monterey Bay CA. Gliders are used to make extensive oceanographic surveys over a six week period. Twelve Slocum and five Spray gliders are deployed during the experiment, to date the most gliders deployed for one project.2004 September November. A Spray glider travels across the Gulf Stream, beginning about 100 miles south of Nantucket, MA and arriving near Bermuda about one month later. The glider travels 600 miles, at a speed of about 0.5 miles per hour or 12 miles per day. 2004 Sea Gliders operate through a typhoon off east Asia2005 Two Sea Gliders fly from Washington coast to Hawaii 6 month mission2005 Gliders launched from US Submarine


Ocean Glider Census ~150 vehicles** June 2006


Slocum Gliders


Benefitscheaper to operate when cf with shipborne observationsOperations in all weatherDesigned for launch, monitor, recover or launch, forget, recover missionsTelemetry rates via low earth orbit satellites are sufficiently inexpensive in both energy (~30 J/kilobyte) and cost (~$0.20/kilobyte) that the data return from a single glider (~120 kilobytes/day) is nearly that originally envisioned for the entire 3000-float Argo fleet using ARGOS while being a factor of ~200 less expensive.


Gliders are tools for appropriate MissionsNeed to balance quality of data spatial requirements temporal requirements costs to select best overall performance and value Glider mission can be changed at any time


Sensor CapabilitiesTemperatureConductivitySalinityDepthWavelength backscatterFluorescence sensorBeam attenuationPassive Acoustics

Real-time data available through the webDelayed mode calibrated, QC data available


Slocum Electric GliderManufactured byWebb Research, USA


SENSORS

CTD (conductivity, temperature, depth) - SeaBirdDissolved oxygen Aanderaa OptodeFluorescence: Chlorophyll-a, CDOM (coloured dissolved organic matter), Phycoerythrin - WetlabsOptical Backscatter:: turbidity through backscattered light at 470nm (blue), 530 nm (Green), 660nm (red).

Slocum Electric Glider


Slocum Electric Glider


Glider Path: 22 days, 486 km, 2420 profiles


Depth-mean currents from glider


Glider cross-section: Sepia depression


Glider cross-section: Temperature


Glider cross-section: Density


Glider cross-section: Backscatter


Glider cross-section: Salinity


Glider cross-section: Density


Glider Purchase: 5 shallow (200m) and 5 deep (1000m)(30%)

People:3 people: glider preparation; Glider deployment and control; data provision (QC)(30%)

Glider deployments:Data transmission costs, shipping(30%)

Schedule:2 shallow water gliders to be delivered in June 20072 deep water gliders to be delivered in November 2007Others to come onboard in 2008.Investment plan


anfog: australian national facility for ocean gliders

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