Autonomous underwater vehicles (AUVs) and investigations of the ice–ocean interface in Antarctic and Arctic waters

• Published in: Journal of Glaciology
• Main Authors: Dowdeswell, J.A., Evans, J., Mugford, R., Griffiths, G., McPhail, S.D., Millard, N., Stevenson, P., Brandon, M.A., Banks, C., Heywood, K.J., Price, M.R., Dodd, P.A., Jenkins, A., Nicholls, K.W., Hayes, D., Abrahamsen, E.P., Tyler, P.A., Bett, B.J., Jones, D.O.B., Wadhams, P., Wilkinson, J.P., Stansfield, K., Ackley, S.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2008
• Subjects: Arctic; Antarctic; Antarc*; Ice Shelf; Ice Shelves; Journal of Glaciology; Sea ice; Tidewater
• Online Access: http://nora.nerc.ac.uk/id/eprint/154735/; https://doi.org/10.3189/002214308786570773

Limitations of access have long restricted exploration and investigation of the cavities beneath ice shelves to a small number of drillholes. Studies of sea-ice underwater morphology are limited largely to scientific utilization of submarines. Remotely operated vehicles, tethered to a mother ship by umbilical cable, have been deployed to investigate tidewater-glacier and ice-shelf margins, but their range is often restricted. The development of free-flying autonomous underwater vehicles (AUVs) with ranges of tens to hundreds of kilometres enables extensive missions to take place beneath sea ice and floating ice shelves. Autosub2 is a 3600 kg, 6.7 m long AUV, with a 1600 m operating depth and range of 400 km, based on the earlier Autosub1 which had a 500m depth limit. A single direct-drive d.c. motor and five-bladed propeller produce speeds of 1-2 ms−1. Rear-mounted rudder and stern-plane control yaw, pitch and depth. The vehicle has three sections. The front and rear sections are free-flooding, built around aluminium extrusion space-frames covered with glass-fibre reinforced plastic panels. The central section has a set of carbon-fibre reinforced plastic pressure vessels. Four tubes contain batteries powering the vehicle. The other three house vehicle-control systems and sensors. The rear section houses subsystems for navigation, control actuation and propulsion and scientific sensors (e.g. digital camera, upward-looking 300 kHz acoustic Doppler current profiler, 200 kHz multibeam receiver). The front section contains forward-looking collision sensor, emergency abort, the homing systems, Argos satellite data and location transmitters and flashing lights for relocation as well as science sensors (e.g. twin conductivity-temperature-depth instruments, multibeam transmitter, sub-bottom profiler, AquaLab water sampler). Payload restrictions mean that a subset of scientific instruments is actually in place on any given dive. The scientific instruments carried on Autosub are described and examples of observational data ...