资源环境科技发展态势分析平台

The National Oceanography Centre's autonomous underwater vehicle Autosub Long Range (ALR), known affectionately around the world as Boaty McBoatface, was successfully recovered last week following its first under-ice mission beneath the Filchner Ice Shelf in West Antarctica. This success marks a significant milestone in proving the vehicle's capability.

Boaty McBoatface being recovered

From January to February 2018, the autonomous underwater vehicle (AUV) was deployed in the southern Weddell Sea during Research Vessel (RV) Polarstern cruise PS111 as part of the Filchner Ice Shelf System (FISS) project - a collaboration involving leading UK research institutions including the British Antarctic Survey (BAS), National Oceanography Centre (NOC), Met Office Hadley Centre, University College London, University of Exeter and Oxford University, and international partners including Alfred Wegener Institute, Germany, and University of Bergen, Norway.

The AUV plays a critical role in the project that aims to investigate and describe the current state of the complex atmosphere-ice-ocean system. Boaty spent a total of 51 hours under the Antarctic ice, travelling 108km over the duration of the deployment. The vehicle reached water depths of 944m, and spent 20 hours exploring beneath a section of the ice shelf that was 550m thick.

Steve McPhail, Head of AUV Development at NOC, said:

I am delighted in the success of this mission. For the engineers involved, this was a very challenging deployment that was not without risk. We knew that the environment was harsh, with -20°C air temperatures and sea temperatures very close to the freezing point of seawater. Under the ice shelves there are significant tidal currents and the high southerly latitudes pose difficulties for the AUV's underwater navigation. Once in the ice shelf cavity we had neither detailed information on the thickness of the ice, nor the depth of the water. We had no communication with the AUV for 90% of its time in the water.

Waiting for the AUV to return after a 48-hour mission into a largely unknown environment is - to say the least - exciting, and as a result I was very relieved each time the AUV turned up, on time and in the right place, circling 900m below the ship. Even then, our problems were not over. With the surface of the sea frozen, we needed RV Polarstern's help to create an ice hole through which we carefully navigated the AUV.

Science Minister Sam Gyimah said:

Global warming is one of the greatest challenges we face today. Boaty's maiden under-ice voyage provides scientists with a greater understanding of the changes that are occurring in Antarctica, which could have a colossal impact on our planet - but, this is only the tip of the iceberg. The government is committed to doing more and, through its ambitious industrial strategy, we are revolutionising industries and society by shifting to clean growth economies - ensuring the UK is leading the way in tackling climate change.

The AUV carried two sets of conductivity, temperature and depth sensors, measuring the salinity and temperature of the water. It was also equipped with a micro-structure probe to measure ocean turbulence, a sensor to measure the amount of phytoplankton in the water (by measuring the fluorescence of their chlorophyll) and a sensor to detect the turbidity of the water. Acoustic instruments also measured the water current up to 80 metres above and below the AUV's position, and accurately measured the depth of the seabed, and the draft of the ice along the vehicle's track.

The Filchner-Ronne Ice Shelf is the second largest of its kind in the world. Covering an area of around 450,000km², it holds a greater volume of ice than any other floating glacier tongue. Climate researchers are particularly interested in whether more glacial ice is currently being transported into the ocean, since this process is related to rising sea levels. In addition, so-called 'deep water' forms near the ice shelf, which is a key driver of global ocean circulation and therefore impacts upon the climate system everywhere on the planet.

The PS111 research team involved many different disciplines including oceanography, meteorology, sea-ice physics, bathymetry, geology and marine biology. Each share an interest in obtaining data from a region that, due to its permanent ice cover, can only be accessed using icebreakers such as the RV Polarstern and AUVs capable of travelling under the ice.

This latest successful mission builds on what Boaty achieved in 2017 when it returned from its first Antarctic adventure with a unique dataset from the Orkney Passage, a region of the Southern Ocean which is around 4,000m deep. This latest mission successfully proves the under-ice capability of the vehicle, making it the first long-range AUV to have successfully explored this challenging environment.

Professor Adrian Jenkins from BAS is leading the investigation. He said:

Understanding the contribution that polar ice sheets make to global sea-level rise is recognised internationally as urgent. The data from this mission are critical for assessing the future stability of Antarctica's Filchner Ice Shelf. The ALR has enabled us to take a small step towards our goal of producing credible sea-level projections for the next 50 years.

Dr Michael Schröder from the Alfred Wegener Institute - Helmholtz Centre for Polar & Marine Research is Chief Scientist on PS111. He said:

The ALR's mission underneath the Filchner Ice Shelf fills the gap between our hydrographic section in front of the ice shelf and the three sub-ice shelf moorings deployed 60km south of the front in austral summer 2016-17 as part of the FISS project. With this data we hope to shed light on the processes controlling the exchange of water masses across the ice shelf front, which might change significantly in the near future.

Further information

Mary Goodchild
NERC News & Media Officer
01793 411939
07710 147485
mary.goodchild@nerc.ukri.org

Notes

1. Autosub Long Range (ALR) specification

• Length: 3·6m
• Width: 1·5m (including wings)
• Mass: 750 kg (in air)
• Running Speed: 0·4 m/s to 1·2 m/s
• Draft: 1·2m
• Minimum Water Depth: 2·5m for launch, 5m for AUV to dive and begin its mission
• Endurance (for trials): 6 days (using rechargeable batteries)
• Communications: Iridium (worldwide); Wi-Fi (at a range of 1km to base station)
• Sensors: Each vehicle is fitted with an acoustic Doppler current profiler (ADCP) and conductivity, temperature & depth (CTD) sensor

2. NOC is the UK's leading institution for integrated coastal and deep ocean research. NOC undertakes and facilitates world-class, agenda-setting scientific research to understand the global ocean by solving challenging multidisciplinary, large scale, long-term marine science problems to underpin international and UK public policy, business and wider society outcomes. NOC operates the Royal Research Ships James Cook and Discovery and develops technology for coastal and deep ocean research. Working with its partners, NOC provides long-term marine science capability including: sustained ocean observing, mapping and surveying; data management and scientific advice. NOC is located at two sites, Southampton and Liverpool, with the headquarters based in Southampton.

Among the resources that NOC provides on behalf of the UK are the British Oceanographic Data Centre (BODC), the Marine Autonomous & Robotic Systems (MARS) facility, the National Tide & Sea Level Facility (NTSLF), the Permanent Service for Mean Sea Level (PSMSL) and British Ocean Sediment Core Research Facility (BOSCORF).

3. NERC is the UK's main agency for funding and managing research, training and knowledge exchange in the environmental sciences. Our work covers the full range of atmospheric, Earth, biological, terrestrial and aquatic science, from the deep oceans to the upper atmosphere and from the poles to the equator. We coordinate some of the world's most exciting research projects, tackling major issues such as climate change, environmental influences on human health, the genetic make-up of life on Earth, and much more. NERC is a non-departmental public body. We receive around £330 million of annual funding from the Department for Business, Energy & Industrial Strategy.

4. NOC is responsible for the National Marine Equipment Pool (NMEP), which is the largest centralised marine scientific equipment pool in Europe, with a diverse range of scientific instruments and equipment capable of gathering data from the surface of the sea to the deep ocean.

Suitable for studying a range of scientific disciplines, the NMEP holds more than 10,000 instruments and technologies, and provides scientists with access to skilled marine technicians and engineers. As part of our national capability remit, the NMEP delivers professional technological support to enable the marine science community to carry out world-class research around the globe. NOC is wholly owned by NERC.

5. BAS, an institute of NERC, delivers and enables world-leading interdisciplinary research in the polar regions. Its skilled science and support staff, based in Cambridge, Antarctica and the Arctic, work together to deliver research that uses the polar regions to advance our understanding of Earth as a sustainable planet. Through its extensive logistic capability and know-how, BAS facilitates access for the British and international science community to the UK polar research operation. Numerous national and international collaborations, combined with an excellent infrastructure, help sustain a world-leading position for the UK in Antarctic affairs.

6. The Alfred Wegener Institute (AWI), Helmholtz Centre for Polar & Marine Research conducts research in the Arctic, Antarctic and oceans of the high and mid-latitudes. It coordinates polar research in Germany and provides major infrastructure to the international scientific community, such as the research icebreaker Polarstern and stations in the Arctic and Antarctica. The Alfred Wegener Institute is one of the 18 research centres of the Helmholtz Association, the largest scientific organisation in Germany.

7. The 118m-long RV Polarstern was first commissioned in 1982. Since then, the icebreaker has completed almost 280 expeditions to the Arctic and Antarctic. Specially designed for working in polar seas, RV Polarstern is currently one of the most sophisticated polar research and supply vessels in the world. And, although it has been in service for over 30 years, it can still fully perform its operational duties thanks to the modern technology on board. RV Polarstern is equipped for research in the areas of biology, geology, geophysics, glaciology, chemistry, oceanography and meteorology. It has nine research laboratories and can be equipped with additional laboratory containers. The 44 crew members support up to 55 scientists. The vessel is operated by AWI in Bremerhaven. The Federal Government, represented by the Federal Ministry of Education & Research (BMBF), owns it.