While most items are being tied down in Bermuda this week as Hurricane Gonzalo takes aim at the island, a yellow undersea glider named “Anna” will swim straight into the storm, piloted by a BIOS scientist taking advantage of a rare opportunity to learn what happens below the ocean surface during a hurricane.
“This is one of the holy grails of glider science, to catch the passage of a major hurricane in the open ocean,” said Ruth Curry, a physical oceanographer who deployed the glider on Tuesday morning about 5 miles east of St. David’s Head in Bermuda.
Past observations of how these storms affect the upper ocean have come almost exclusively from instruments on moorings that happen to be in the storm’s path.
Anna—recently back from the glider’s inaugural 100-day mission—can travel thousands of miles through the ocean on a single journey, providing a detailed picture of storm impacts. The glider dives from the sea surface to 1,000 meters depth (3,000 feet), covering about 15 miles per day and communicating with shore-based scientists via satellite when at the surface. Anna relays measurements of ocean salinity, temperature, current speed, oxygen, and other collected data, and downloads any new instructions to her mission.
Curry expects the data gathered to include recordings about the waters around Bermuda, which will cool off by several degrees as Gonzalo’s winds draw heat from the ocean into the atmosphere, and create strong currents 50 to 60 feet below the sea surface.
While residents are now scrambling in Bermuda to protect equipment, boats, and homes from the weather, Curry said the glider is designed to withstand the coming turbulent conditions.
“Anna will be just fine,” said Curry, “With all the wind and surf, there may be drops in satellite communications, but (the glider) is programmed to call back and resume transmissions. If we lose our internet connection here in Bermuda, Anna will call to a backup server in the U.S.”