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Maritime Forum

Map of the Week – Underwater gliders

The Map of the Week shows the position of underwater gliders that automatically collect ocean data and monitor the seas. This information is supplied in near real-time by EMODnet Physics.


Ocean observation is key to understanding the current state of oceans and seas. A wide range of in-situ oceanographic instruments are deployed around the world by research institutes. This includes, for example, Argo floats, drifting buoys and underwater gliders. This week’s Map of the Week focuses on underwater gliders which automatically collect ocean data and monitor the seas by following an up-and-down, sawtooth-like profile through the water. They are equipped with sensors taking many different types of measurements such as temperature, conductivity (to calculate salinity), currents, chlorophyll fluorescence (allowing for assessment of phytoplankton1 biomass) and bottom depth. They navigate with the help of Global Positioning System (GPS) communication at the surface, pressure sensors, tilt sensors, and magnetic compasses providing data on temporal and spatial scale.

About 2,000 autonomous instruments (such as profiling floats and drifting buoys) must be deployed every year to sustain the Global Ocean Observing System (GOOS)2. Usually, ocean observing instruments are deployed through oceanographic research ships. However, during this year’s Vendée Globe Race, ten skippers are also carrying and deploying scientific instruments to support the Global Ocean Observing System within the framework of the United Nations Decade of Ocean Science for Sustainable Development (2021-2030) 2. This provides an opportunity to reach remote, less sampled areas. In addition to in-situ oceanographic instruments, remote sensing observations are also collected by instruments mounted on Earth-orbiting satellites like those provided by the European Space Agency. The recently launched Copernicus Sentinel-6 Michael Freilich satellite, for example, will provide high-precision measurements of global sea level.

Given the importance of ocean observation to adequately address the changes, the threats and the opportunities we face, European Union Member States currently spend more than €1.5 billion a year in observing the ocean3. To further optimise ocean observation, the European Commission has recently launched a public consultation to seek stakeholders’ views on the main challenges facing those engaged in all aspects of ocean observation as well as those who rely on them. The public consultation is open until 19 February 2021.

Dive into the map to see the position of underwater gliders and click on them to learn more!

Access the map

The data in this map are provided by EMODnet.

1 Phytoplankton: miniscule single-celled algae that drift at the surface of the ocean