An autonomous, underwater vehicle monitors ocean conditions and water parameters in treacherous, ice filled arctic waters. The information it collects supports the understanding of ocean and related climate changes.

This photo shows the seaglider clearing its antennae from the water to send off data and receive mission instructions before plunging back into the arctic waters. The photo below shows the complete glider, which is about 3 metres (10 foot) long.

The ocean currents, which are strongly dependent on density differences in water, have a major effect on sea temperatures around the world, which in turn effects the weather. One critical water flow is that from the Arctic through the Canadian Arctic Archipelago and Davis Strait into the Labrador Sea . With climate change and the melting of the ice cap an increase in water density can be expected in the Labrador sea, which could effect currents throughout the world.

Oceanologists and climatologists need to monitor this flow, but the normal technique of mooring instruments to the ocean bed is difficult because of the ice in the area. Propeller driven unmanned underwater vehicles also have difficulty in operating in this environment and need much closer maintenance and management. In particular they need to be recovered within hours of surfacing while the seaglider can wait for weeks for recovery.

The University of Washington’s Applied Physics Laborator has developed and optimised an under-ice seaglider which has just operated independently for a record six months, collecting and relaying a vast amount of information. The seaglider which can operate up to 1,000 metres (3,300 feet) below the surface has no propulsion but glides, by controlling its buoyancy and its attitude (angle compared to the horizontal). The buoyancy is adjusted by inflating or deflating an oil filled bladder, while the seaglider’s  attitude is adjusted by moving the weighty battery pack backwards and forwards along a longitudinal shaft.