Swarm of Marine Gliders

• Subject Area: Atmospheric Science, Oceanography and Climate Research
• Term: Funded in 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 544335393

Marine gliders, a type of autonomous underwater vehicle, are a measurement platform which carries oceanographic sensors to remote regions of the worlds’ oceans. They are characterised by long-endurance (up to 1 year) and can be remotely piloted from shore. The measurements they make depend on the sensor payload, and may include ocean temperature, salinity, dissolved oxygen concentration, bio-optical measurements, turbulence, current speed and direction, and more. Gliders have been in operation since the early 2000s, commercially-available some years later, and are now relatively prolific (with 10s of groups across the world using them for oceanographic research). Several platforms are available to make oceanographic measure- ments; traditional platforms include research vessels, profiling floats and moorings. Gliders provide a complementary approach to these platforms. Compared to ships, gliders are slow (research ships travel at 18 kph; gliders at 20 km/day). However, their endurance enables measurements far longer than a typical research cruise (which is typically up to 1 month) so that seasonal variations can be studied. Compared to profiling floats, gliders can be piloted to specific locations or in a measurement pattern, whereas floats drift wherever the currents take them. Compared to moorings, gliders can measure near surface and covering spatial distances, while moorings are fixed-point and typically sub-surface. Here we propose a swarm of marine gliders. The specific requirements are: long lifetime (6 months or longer), 1 km water depth and the ability to operate sensors (temperature, salinity, pressure, oxygen, bio-optical parameters). The deployment of a swarm of gliders (simultaneous deployment of several gliders) compensates for measurement limitations associated with slow glider speeds and allows a spatial view of the ocean structure and variability to be captured, particularly at the ocean mesoscale (horizontal scales of 10-100 km) and sub-mesoscale (horizontal scales of 0-1 km). These small scales in the ocean are increasingly being recognised as having a leading influence on the mean state and tendency of the large-scale ocean circulation and climate, but are otherwise challenging to observe using traditional platforms. Therefore, we are applying for funding for a swarm of gliders to enable the analysis of oceanographic processes spanning scales of 1-100 km. The scientific problems to be investigated with this swarm include: - How freshwater from polar ice cap melting changes regional and global ocean circulation; - How the ocean conveyor redistributes heat, freshwater and other properties around the oceans; - How small-scale interactions between the ocean and ice set basin-scale ocean properties.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Schwarm von Meeresgleitern
• Instrumentation Group: 0480 Spezielle Fahrzeuge und Geräteträger der Meeresforschung (außer Schiffe 240)
• Applicant Institution: Universität Hamburg
• Leader: Professorin Eleanor Frajka-Williams, Ph.D.