Introducing the Polar AUV Task Team

Autonomous Underwater Vehicles (AUVs) are free-swimming robots that are designed to explore the global ocean from top to bottom, pole to pole. Taking the human out of the loop, AUVs are best suited to filling data gaps in extreme environments such as abyssal plains, hydrothermal vents and under ice. The first polar AUV missions were legendary – in 1996 Theseus, a 10.7 m long AUV built by International Submarine Engineering – travelled 180 km beneath Arctic sea ice deploying fibre-optic cable as it went and then returned to shore (Ferguson, 1998). Such a bold mission, driven by industry, laid the foundation for the research community to envisage the science these machines could facilitate.

For over two decades, polar AUV research was led by the United Kingdom’s Autosub program based out of the National Oceanographic Centre in Southampton. In 2004 Autosub-II undertook its first long-range missions beneath Arctic fast-ice, and in 2005 went 30 km beneath the Fimbul Ice Shelf in Antarctica (Dowdeswell et al., 2008). Incredible achievements for both marine engineering and polar science. Unfortunately, great marine autonomy rewards come with inherent risk and Autosub-II was lost on its very next mission beneath the ice shelf. To their credit, this inherent risk was understood by the UK community and at the time of the loss, its replacement Autosub-III was already funded and under construction.

Figure 1: The United Kingdom’s National Oceanographic Centre Autosub Long-Range (LR). Image credit Alexander Phillips (NOC). Autosub-LR specialises in long endurance/range missions.

Figure 2: Sweden’s Hugin AUV ‘Ran’. Image credit Filip Sted (Gothenburg University). RAN specialises in high-quality bathymetric mapping.

The NOC Autosub fleet has continued to grow and evolve – today it has 4 vehicles, its most recent Antarctic member being Autosub-Long Range (LR) – an AUV capable of multi-day, 1000 km missions under ice (Figure 1). Importantly, the UK is no longer alone in its efforts as a new community of long-range AUV programs addressing Antarctic ice shelf research has emerged. Sweden and Australia have both invested heavily in polar AUVs, acquiring Hugin (Figure 2) and ISE Explorer AUVs (Figure 3), respectively. In addition, countries like Japan and China have their own polar AUV development programs.

This exciting new era of polar AUVs offers great opportunities to the global Antarctic science community. Focusing on ice shelf research, long-range AUVs are the only way to address the critical gaps in our knowledge of the geometry and melting processes beneath Ice shelves, the seafloor below, the ice thickness above and the water properties between. Every observation platform has strengths and limitations. The great opportunity now is to make coincident observations with multiple platforms to facilitate complex process studies (Figure 4). Ten years ago, the goal for AUVs was getting as close as possible to the back/grounding line of an ice shelf where the strongest melting is occurring. Today, it is arguably getting AUVs to regularly survey deep beneath ice shelves in coordination with under-ice ocean gliders and through-ice borehole measurements including tethered platforms like IceFin (Spears et al., 2015).

Figure 3: Australia’s ISE Explorer ‘nupiri muka’ has a custom-built trace metal clean water sampler.

Figure 4: Schematic of detailing the integrated observation platforms being utilised by the international community to study the Thwaites Glacier (Scambos et al., 2017).

While the technology underpinning AUV operations has continued to improve, the risks inherent to working in the extreme conditions of Antarctica remain unchanged. In the 2018/2019 season three large AUVs went to Antarctica and two returned. While long-range AUVs are best deployed in concert with other observation platforms, they come with significant logistic overhead and quickly dominate the deck-plan/workplans of icebreakers/research expeditions. These research expeditions, sensitive to the financial and strategic direction of their national funding agencies are few and far between, with long lead and lag times. And the clock is running on how long the global climate science community can afford to carry the data gaps these platforms promise to fill. Accordingly, there is great motivation for the different long-range polar AUV programs to work together to minimize risk and maximise synergistic opportunities for deployments. This was the fundamental reason for the formation of the SOOS Polar AUV Task Team.

In July 2018 there was an Australian-led initiative to form an International Experts Panel on Polar AUV. Australia was preparing for its first Antarctic deployments of nupiri muka, its 7-8m long Explorer-class AUV from International Submarine Engineering and wanted to bring together a collective of past and present engineers and scientists with experience in polar AUV operations. It was also open to all current SOOS science teams developing new plans for Antarctic AUV research. The panel met in Vancouver to review Australian and Swedish plans for 18/19 and provide feedback to assist in risk mitigation and scientific return. The key outcome from this group was the vital importance of optimising clear and definitive scientific objectives relative to engineering best practises (King et al., 2018). The group met again in 2019, this time hosted by the Swedish Hugin - RAN team in Horten, Norway. Again, this was an opportunity to review plans for the 19/20 deployment of nupiri muka – this time with the Korean Polar Research Institute (KOPRI) from the RV Araon at the Thwaites Glacier.

With growing membership and interest, it was decided to split the group into sub-groups of AUV engineers and AUV Principal Investigators with strong linkages. In May 2019, a proposal to form a SOOS Task Team was approved by the SOOS Executive Committee, with an initial goal of sharing data and logistic opportunities. Plans for 2020 were interrupted by COVID and a decision was made to re-focus the Task Team on the emerging likelihood that all three large AUV programs would be heading to the Thwaites Glacier in the 21/22 season. Accordingly, the leadership of the Task Team was established with the key Chief AUV Investigators from the UK (University of East Anglia), Sweden (University of Gothenburg) and the Republic of Korea (Korean Polar Research Institute)/ Australia (University of Tasmania). It was also recommended that given the focus on Thwaites, the Task Team be embedded in the SOOS Amundsen and Bellingshausen Sector (ABS) Regional Working Group. With logistics already outlined for each of the groups, the new objective was for the core Chief Investigators to work together in the development of coordinated science objectives across the three teams. The Task Team met in late 2020 and was formalised in early 2021, including other core Antarctic AUV and associated autonomous observation platform representation. For the first time the community was able to see the broad ambitions for each group to deploy east and west of the Thwaites Glacier, exploring deep beneath the ice to examine hypothesised pathways of warm ocean water and to link up with other ‘through-ice’ observation teams (Figure 5).

Three large AUVs from the UK, Sweden and Australia/Korea, all vying to get to the back of a critically unstable, globally significant ice shelf is reminiscent of the race to the South Pole, or the Moon in terms of challenge, excitement and risk. The important difference this time is that while each AUV team will be doing its best to explore as far and wide beneath the Thwaites Glacier, they’ll be doing it in close cooperation with each other. Antarctica will undoubtedly throw everything it has got against these expeditions but working together through this SOOS initiative ensures the greatest chance of overall success for the Antarctic research community and by extension humankind.

Figure 5: Preliminary AUV tracklines (red dashed) proposed for the 2021/2022 season, east and west of the Thwaites Ice Tongue, targeting pathways of warm water incursions and through-ice measurements (blue and yellow stars).

Name Affiliation

A/Prof. Guy Williams (chair) University of Tasmania, Australia

Prof. Karen Heywood (co-chair) University of East Anglia, United Kingdom

Prof. Anna Wåhlin (co-chair) University of Gothenburg, Sweden

Dr Won Sang Lee (co-chair) Korean Polar Research Institute, South Korea

Dr Pier van der Merwe University of Tasmania, Australia

Dr Takeshi Tamura National Institute of Polar Research, Japan

Dr Dake Chen Second Institute of Oceanography, China

Dr Joanne O'Callaghan National Institute for Water and Air, New Zealand

Dr Pierre Dutrieux British Antarctic Survey, United Kingdom

Dr Andrew Martin University of Tasmania, Australia

Dr Britney Schmidt Cornell University, United States

References

Dowdeswell, J., et al., (2008), ‘Autonomous underwater vehicles (AUVs) and investigations of the ice–ocean interface in Antarctic and Arctic waters’, Journal of Glaciology, 54(187), 661-672. doi:10.3189/002214308786570773

Ferguson, J. S. (1998), ‘The Theseus autonomous underwater vehicle. Two successful missions’, Proceedings of 1998 International Symposium on Underwater Technology, Tokyo, Japan, 1998, pp. 109-114, doi: 10.1109/UT.1998.670072.

King, P., et al., (2018), ‘Deploying an AUV beneath the Srsdal Ice Shelf: Recommendations from an expert-panel workshop’, Proceedings of the 2018 IEEE/OES Autonomous Underwater Vehicle Workshop (AUV). doi:10.1109/AUV.2018.8729786

Scambos, T.A., et al., (2017), ‘How much, how fast?: A science review and outlook for research on the instability of Antarctica's Thwaites Glacier in the 21st century’, Global and Planetary Change, Volume 153, Pages 16-34, ISSN 0921-8181, https://doi.org/10.1016/j.gloplacha.2017.04.008.

Spears, A., et al., (2015) ‘Design and Antarctic testing of the Icefin vehicle’, OCEANS 2015 - MTS/IEEE Washington, Washington, DC, USA, pp. 1-6, doi:10.23919/OCEANS.2015.7401886.