Map satellite

Secrets of the tropical seabed unearthed as mission to map all of the world’s seabed gains momentum

London, February 16, 2022 – Satellite technology has been used to map shallow areas of the Cook Islands seabed in detail never before seen by scientists from the National Institute of Water and Atmospheric Research (NIWA) and Toitū Te Whenua Land Information New Zealand (LINZ) working with satellite data analysis company, EOMAP GmbH. The work was carried out as part of The Nippon Foundation-GEBCO Seabed 2030 project – a collaborative project to bring together all available bathymetric data to produce the definitive map of the global ocean floor.

The discovery coincides with the One Ocean Summit, held in France, during which UNESCO called on the international community to step up efforts to map the rest of the ocean floor – 20.6% have been mapped nowadays.

The Suwarrow and Pukapuka map in the Cook Islands builds on decades-old records, with more precise positioning and wider coverage, including information on harder-to-reach areas such as shallow lagoons.

The image shows bathymetry derived from the Pukapuka Atoll satellite overlaying pre-existing data in the GEBCO grid. 1 credit

Kevin Mackay, a marine geology researcher at NIWA, also leads Seabed 2030’s South and West Pacific Ocean Data Center – one of the project’s four regional centers, each responsible for data collection and mapping on his territory.

Commenting on the use of satellites as a tool for measuring shallow parts of the ocean floor, Kevin says: “To measure the depth of the ocean, traditionally you had to send out a boat with an echo sounder, which costs a lot of money. silver and can be dangerous in rough, shallow seas.

“With satellites, we can access places that are extremely remote, with less carbon footprint and without having to put people at risk.”

The images come from two commercial satellites, World-View-2 and GeoEye-1, which provide very high resolution images of the Earth’s surface. As a result, the data accuracy is greatly improved. Satellite bathymetry can be used up to a maximum water depth of 30 m.

Stuart Caie, head of hydrographic surveys at LINZ, said: “The technology and the processes are very clever – the satellite can see the shallow seabed in exquisite detail, but to infer the depth of the water the software has to get rid of obstacles such as shadows and waves.

“The software therefore removes water and uses complex algorithms to produce depth estimates before creating a map with colors of what the seabed would look like without water, which we then use.”

Seabed 2030 – which is officially recognized as a flagship program of the Decade of the Oceans – is a collaborative project between the Nippon Foundation and the General Bathymetric Chart of the Oceans (GEBCO) to inspire comprehensive global ocean mapping and compile all bathymetric data in the GEBCO ocean map available free of charge. GEBCO is a joint program of the International Hydrographic Organization (IHO) and the Intergovernmental Oceanographic Commission (IOC).

The Regional Center for the South and West Pacific Ocean is made up of NIWA, GNS Science and LINZ, which work together to map more than 123 million km2 of ocean.

The nautical chart will be released in February and is expected to improve ocean safety and scientific knowledge.