Roadmap for Future Ocean Floor Mapping

About 71% of the Earth is covered by the World Ocean for which the bottom topography (bathymetry) is far less known than the surfaces of Mercury, Venus, Mars, and several planets’ moons, including our own. Mapping through ocean water deeper than a few meters excludes the efficient use of electromagnetic waves such as radar and light, which forms the basis for methods used during terrestrial and extra-terrestrial mapping missions. While ocean surface height measured by satellites can be used to derive a coarse view of the ocean floor, it does not have sufficient resolution or accuracy for most marine or maritime activities, be it scientific research, navigation, exploration, shipping, resource extraction, fisheries or tourism. Traditional bathymetric mapping techniques rely on acoustic mapping technologies deployed from surface or submerged vessels and require broad international coordination and collaboration towards data assimilation and synthesis.

Mapping the entire World Ocean floor is an ambitious effort, specifically considering that 50% is deeper than 3200 m and large parts
at high latitudes are permanently covered by sea ice.

Systematic acquisition of deep ocean (over 200 meters) bathymetric data began in earnest with the British Challenger expedition (1872–1876), generating 492 deep-sea soundings using a line to which a weight was attached. Deep-sea line soundings continued for the following 50 years, until echo-sounding technology became efficient. Nearly a century later, however, more than 80% of the World Ocean floor is still not mapped even at a resolution of 1 kilometer using the echo sounding method.

The Nippon Foundation and GEBCO announced the launch of Seabed 2030. Seabed 2030 is a collaborative project between GEBCO and the Nippon Foundation with the aim to facilitate the complete mapping of the ocean floor by the year 2030. It builds on more than 100 year’s of GEBCO’s history in global seafloor mapping.

The 2030 goal is a 100 meter mapping resolution for the entire ocean. They will define a series of targets with varying resolutions as a function of water depth. Seabed 2030 thus provides a Road Map, or guidelines and instructions, for future ocean floor mapping that builds on the century-long GEBCO legacy and the human capacity built by the GEBCO−Nippon Foundation training program over the past decade.

Seabed 2030 will compile all available and newly collected bathymetric data into a high-quality, high-resolution digital model of the World Ocean floor. Given the vast expanses of the oceans, this can only be achieved through international coordination and collaboration with respect to data acquisition, assimilation and compilation. Regional Mapping Projects will be established focused on gathering all bathymetric data from a specific region into a digital database that will enable experts to produce the best possible gridded bathymetric model, a digital 3D representation of the seafloor topography.

The past few decades have seen consistent improvements in the accuracy, resolution, and seafloor coverage offered by echo-sounding and LIDAR methods. The most widely used acoustic mapping technology is based on the multibeam echo sounder with the capability of mapping a wide swath underneath the vessel. The width of a mapped swath of the seafloor by multibeam sonars is approximately five times the water depth and often more. Interferometric sonars exist and are being developed with wider swath widths, and specifically suited for shallow water mapping or installation in AUVs due to their smaller size. However, the quality of depth measurements of interferometric sonars is not yet at the level of conventional multibeam echo sounders. The evolution of technology may see sonars based on a mix between the interferometric and more conventional multibeam technology. If the size and power requirements of a sonar with multibeam capacity could be considerably reduced, gliders may be used for bathymetric mapping. This would extend the mapping range compared to what is achieved with the currently available AUVs.

Ocean Discovery Xprize – a 3 year challenge and $7 million prize

The Shell Ocean Discovery Xprize is a $7 million global competition challenging teams to push the boundaries of ocean technologies by creating solutions that advance the autonomy, scale, speed, depths and resolution of ocean exploration.

The success of this prize will allow us to fully explore and map the ocean floor, and uncover our planets greatest wonder and resource for the benefit of humanity. The National Oceanic and Atmospheric Administration’s $1 million bonus prize will incentivize teams to develop technologies to detect the source of chemical and biological signals underwater.

Teams will compete in two rounds of testing that:

Must launch from shore or air and, with restricted human intervention, their entries will have limited number of hours to explore the competition area (at depths of 2000 and 4000 meters) to produce:

1. a high resolution bathymetric map
2. images of a specified object
3. identify archaeological, biological or geological features

Nineteen teams drawn from 13 different countries are currently having their solutions assessed before being asked to demonstrate the innovations next year in a major field trial.

This will see the teams have to map at least 50% of a 4km-deep, 500-sq-km zone of ocean floor inside 24 hours. Features as small as 5m must be observable. Imagery must also be acquired in addition to the depth data.

Team Tao’s swarm system aims to be 100 times cheaper than traditional ship-borne mappers
The vision is for an autonomous surface vehicle that can carry, deploy and collect a total of 24 robots
BEMs would be released 12 at a time in a dive cycle lasting just over the hour. BEMs spin as they scan
Thrusters enable them to crab across the measurement field. Sub-50cm resolution is being sought
When BEMS are picked up, they dump their data and are put on charge to await the next dive cycle. The surface vessel uploads the data to the cloud
The entire system is expected to cost £1m. It has been designed to fit in a standard shipping container for worldwide use

The XPRIZE Foundation had also hoped to run a 2km-deep trial at this stage of the competition off Puerto Rico. But this became impossible following the damage inflicted on the island by Hurricane Maria.

“The delay has worked for us, for sure,” says Dale. “If we’d had to go to Puerto Rico now we’d probably only have two BEMs. We aim now to go to the final with five but that will demonstrate our system. For the future, we just have to scale up to a bigger surface vessel. With the full system – a 12m autonomous surface vessel and 24 BEMs – we should be able to map more than 200 sq km a day.”

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