The temperature, salinity and oxygen data gathered by the Seagliders will help the North Pacific Acoustics Laboratory scientists better understand acoustic propagation – how sound is affected as it moves through the ocean. Acoustics can be used to probe such things as long-term ocean temperature changes and climate variability, and the role of internal waves in ocean mixing, Howe says.

Gliders also could be used to monitor changes in the world’s oceans because of storms, such as hurricanes, and other natural events, such as El Niño. Sonar and other sensing devices mounted on gliders may one day routinely scan harbors and seaports for explosive mines or detect divers in areas where they don’t belong.

A Seaglider can dive from the surface down 3,300 feet and back up every 3 to 9 hours. It remains at the surface 5 minutes to transmit ocean data that it has collected, relay its position and receive instructions via the Iridium satellite phone network, before diving again. It travels at half a knot, driven not by a spinning propeller but by buoyancy control: a hydraulic system moves oil in and out of an external rubber bladder to force the glider up or down through the ocean. Moving its battery pack causes it to pitch its nose up or down or roll its wings to change compass heading.

In the recent deployment in the North Pacific, UW engineers Jim Luby and Neil Bogue piloted one Seaglider on a direct course to Kauai, while the other was sent to gather data for 620 miles due west before being nudged southwest toward Kauai. Both were navigated around Kauai to where UW Applied Physics Laboratory’s Jim Mercer and Jason Gobat led a team to retrieve them.

From a UW press release.