The Ocean Glider Program
The world's oceans are vast and cannot be properly described using research vessels only. Satellite technology has greatly improved our ability to obtain global coverage of some environmental variables but satellites cannot see into the ocean's interior. Autonomous gliders can help to fill the gaps between shipboard sampling and satellite imagery.
The Ocean Tracking Network (OTN) deploys two Teledyne Webb Research Slocum electric gliders (OTN200 and OTN201) near continuously along the Halifax Line, running from Chebucto Head to approximately 250 km offshore. Their mission is to provide oceanographic context for the animal tagging efforts of OTN. Ultimately, data from the gliders will provide foundations for models of ocean dynamics that will be related directly to the activities of tracked species.
In addition OTN operates a Liquid Robotics wave glider (SO174, codename 'DL') whose primary mission is to upload data from bottom-mounted acoustic receivers and then transmit that data back to shore via satellite. The Wave Glider itself is also a mobile receiver listening for tagged animals. While performing these two functions it also collects oceanographic data on the ocean’s surface.
This submarine platform uses a buoyancy drive to achieve depths of up to 1000m, and averages 1 km/hr. Powered by alkaline or lithium battery cells, the Slocum glider can be deployed for a month at a time, taking measurements of ocean physics, chemistry and biology on a time-scale of seconds. Plans to include Vemco VMTs on our Slocum glider deployments are nearly complete.
This surface-based platform relies on differential wave height to drive its 7m deep submarine platform forward through the water. Its float houses the onboard computer, satellite data-link, GPS and most instrumentation. Able to detect ships, respond to radar pings, and measure meteorological and near-surface ocean conditions, the Wave Glider's solar panels allow it to remain at sea for long periods of time. Its reliance on solar power limits its sampling rate to a time-scale of minutes. OTN's Wave Gliders also feature acoustic receivers, allowing us to detect tagged animals on our missions.