Drivers of Oceanic Change in the Amundsen Sea (DeCAdeS)
Lead Research Organisation:
University of Sheffield
Department Name: Geography
Abstract
Sea level rise is one of the most disruptive consequences of global warming, threatening coastal populations and infrastructure worldwide. If we are to develop strategies to either adapt to, or mitigate against, that threat, we need to know what to expect in the future. The biggest uncertainty in estimates of future sea level is the contribution of the vast Antarctic Ice Sheet. Observations of thinning in some parts of the ice sheet have led to suggestions that an irreversible change may already be underway that could add over a metre to sea level over the coming centuries.
Thinning is most prominent in the Amundsen Sea sector of the ice sheet, where it has been observed to spread inland from the coast, and to affect neighbouring outflow glaciers in a similar way. Those facts demonstrate that some change in ocean-driven melting of the glacier termini has been the trigger of change, leading to a widespread belief that warming of the ocean waters, driven ultimately by global warming, is responsible. However, observations of ocean temperature in the Amundsen Sea suggest a more complex history. The records start in 1994, and include only a few observations prior to 2009, but suggest cycles between warm and cool conditions occurring over decadal periods. That motivates a major rethink of how the ocean interacts with the ice sheet to produce the observed thinning.
In this project we plan to exploit new techniques to fill the gaps in the record of ocean temperature change in the Amundsen Sea. We will modify a robotic submarine so that it can over-winter beneath the pack ice, periodically measuring the properties and strength of the currents carrying warm water towards the ice. Those measurements will be complemented by fixed instruments that record continuously at selected locations and seal-borne sensors that will record the depth of the warm water wherever and whenever the seals dive below the surface to feed. We will relate these detailed observations of what is happening below the sea surface to changes in the height of the sea surface that can be detected by satellites. That will enable us to exploit the satellite records collected over three decades to infer past changes in the sub-surface ocean. The results will allow us to confirm the timing and magnitude of recent warm and cool cycles and relate them directly to the records of ice sheet thinning.
To extend our knowledge of Amundsen Sea temperatures beyond the satellite era we will use a numerical model of the ocean circulation in the region to identify the patterns of atmospheric forcing that were responsible for the changes in temperature that we have observed. We will then examine reconstructions of the past atmospheric circulation to generate a history of the key atmospheric changes. Finally, we will investigate how those changes in the regional atmospheric circulation relate to global-scale atmospheric change, providing us with the longer-term perspective that is needed to address the questions of what past conditions initiated the current thinning and what the future might hold.
Should we find that the most recent decade is typical, and that earlier decades have been characterised by similar cycles in ocean forcing, we will have shown that predicting the future of the ice sheet requires an understanding of its response to extremes. Much like the coastal engineer planning for the impacts of climate change, who must construct sea defences to protect against the extreme levels generated when storm surges coincide with high tides, we need to understand how long and severe the warm extremes in the Amundsen need to be in order to trigger episodes of ice sheet thinning. We also need to know what combination of larger-scale modes of atmospheric variability produces the "perfect storm" in the Amundsen that can push the ice sheet out of balance. Our project will deliver the knowledge needed to address those critical questions.
Thinning is most prominent in the Amundsen Sea sector of the ice sheet, where it has been observed to spread inland from the coast, and to affect neighbouring outflow glaciers in a similar way. Those facts demonstrate that some change in ocean-driven melting of the glacier termini has been the trigger of change, leading to a widespread belief that warming of the ocean waters, driven ultimately by global warming, is responsible. However, observations of ocean temperature in the Amundsen Sea suggest a more complex history. The records start in 1994, and include only a few observations prior to 2009, but suggest cycles between warm and cool conditions occurring over decadal periods. That motivates a major rethink of how the ocean interacts with the ice sheet to produce the observed thinning.
In this project we plan to exploit new techniques to fill the gaps in the record of ocean temperature change in the Amundsen Sea. We will modify a robotic submarine so that it can over-winter beneath the pack ice, periodically measuring the properties and strength of the currents carrying warm water towards the ice. Those measurements will be complemented by fixed instruments that record continuously at selected locations and seal-borne sensors that will record the depth of the warm water wherever and whenever the seals dive below the surface to feed. We will relate these detailed observations of what is happening below the sea surface to changes in the height of the sea surface that can be detected by satellites. That will enable us to exploit the satellite records collected over three decades to infer past changes in the sub-surface ocean. The results will allow us to confirm the timing and magnitude of recent warm and cool cycles and relate them directly to the records of ice sheet thinning.
To extend our knowledge of Amundsen Sea temperatures beyond the satellite era we will use a numerical model of the ocean circulation in the region to identify the patterns of atmospheric forcing that were responsible for the changes in temperature that we have observed. We will then examine reconstructions of the past atmospheric circulation to generate a history of the key atmospheric changes. Finally, we will investigate how those changes in the regional atmospheric circulation relate to global-scale atmospheric change, providing us with the longer-term perspective that is needed to address the questions of what past conditions initiated the current thinning and what the future might hold.
Should we find that the most recent decade is typical, and that earlier decades have been characterised by similar cycles in ocean forcing, we will have shown that predicting the future of the ice sheet requires an understanding of its response to extremes. Much like the coastal engineer planning for the impacts of climate change, who must construct sea defences to protect against the extreme levels generated when storm surges coincide with high tides, we need to understand how long and severe the warm extremes in the Amundsen need to be in order to trigger episodes of ice sheet thinning. We also need to know what combination of larger-scale modes of atmospheric variability produces the "perfect storm" in the Amundsen that can push the ice sheet out of balance. Our project will deliver the knowledge needed to address those critical questions.
Planned Impact
This project is designed to deliver the following societal impact: increased understanding and awareness of the interplay between ocean circulation, ice shelves, and sea level rise, with a specific focus on how autonomous vehicles can enable the scientific community to monitor better these key sea level regulators. This outreach will have a particular focus on the Amundsen Sea and the UK's role in studying that crucial region. As a result of this scientific activity, in the coming decades we will have reduced uncertainties in sea level rise projections. Global societies will be better informed and hence better able to plan for and adapt to future sea level rise, protecting low-lying communities, infrastructure, and the associated economic activity.
To achieve this, we propose the following impact objectives:
(i) Establish a dialogue between scientists and policymakers regarding ocean circulation, ice shelves, and sea level rise, with a focus on next-generation autonomous vehicles.
(ii) Nurture and train early career scientists, giving them skills to equip them for a productive independent career and to meet national skills shortages.
(iii) Engage with young people across a wide age range on oceanography, glaciology, sea level rise, and autonomous vehicles.
(iv) Engage with the general public on oceanography, glaciology, climate change, sea level rise, and autonomous vehicles.
By meeting these objectives, this research will provide benefits to the following groups:
(i) Policymakers (e.g. DEFRA).
(ii) Coastal planners and communities.
(iii) School groups (primary, secondary, and higher education).
(iv) General public.
To achieve this, we propose the following impact objectives:
(i) Establish a dialogue between scientists and policymakers regarding ocean circulation, ice shelves, and sea level rise, with a focus on next-generation autonomous vehicles.
(ii) Nurture and train early career scientists, giving them skills to equip them for a productive independent career and to meet national skills shortages.
(iii) Engage with young people across a wide age range on oceanography, glaciology, sea level rise, and autonomous vehicles.
(iv) Engage with the general public on oceanography, glaciology, climate change, sea level rise, and autonomous vehicles.
By meeting these objectives, this research will provide benefits to the following groups:
(i) Policymakers (e.g. DEFRA).
(ii) Coastal planners and communities.
(iii) School groups (primary, secondary, and higher education).
(iv) General public.
Organisations
People |
ORCID iD |
| Julie Jones (Principal Investigator) |
Publications
Caton Harrison T
(2024)
Advances and Next Steps in Observing and Modeling Antarctica's Coastal Winds
in Bulletin of the American Meteorological Society
| Description | PICANTE - Processes, Impacts, and Changes of ANTarctic Extreme weather |
| Amount | £2,427,403 (GBP) |
| Funding ID | NE/Y503290/1 |
| Organisation | United Kingdom Research and Innovation |
| Sector | Public |
| Country | United Kingdom |
| Start | 02/2024 |
| End | 10/2028 |
| Description | Talk to the Lincoln branch of the Geographical Association |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Public/other audiences |
| Results and Impact | I gave a talk entitled 'Antarctic Climate Change and Variability' to the Lincoln branch of the Geographical Association, on Thursday 26th February at Bishop Grossesteste University, Lincoln. The audience of around 20 attendees was comprised of members of the general public (members of the GA), as well as academics from the Department of Geography at the University of Lincoln. A local school was supposed to connect online, but the technology did not work unfortunately so they could not join. The intention of the talk was to introduce audience members to the science around understanding recent climate change in Antarctica, highlighting the strong links between the atmosphere, ocean and cryosphere, and the roles of human and natural influences - science at the core of the DeCAdeS project. The talk was around 45 minutes, followed by 15 minutes of Q&A, with audience members asking some insightful and interesting questions, and expressing that they found the talk interesting and enjoyable, and that they learnt a lot from the presentation. One audience member had worked for the British Antarctic Survey for several decades in expedition support, and said that they learn a lot too! |
| Year(s) Of Engagement Activity | 2024 |
| Description | Talk to the York Branch of the Geographical Association |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Schools |
| Results and Impact | I gave a talk entitled 'Antarctic Climate Change and Variability' to the York branch of the Geographical Association, at Bootham School, York, on 18th Feb 2024. The audience of 107 attendees was mostly comprised of 6th form students from local schools, as well as from a school in Leeds, and a number of members of the general public (members of the GA), and local undergraduate students. The intention of the talk was to expose students to university-style lectures and current research methodologies and results which they cannot find in their textbooks, as well as to introduce the audience to the importance and challenges of understanding Antarctic Climate Change. The talk was around 45 minutes, followed by 15 minutes of Q&A. In my talk, I introduced the students to the science around understanding recent climate change in Antarctica, highlighting the strong links between the atmosphere, ocean and cryosphere, and the roles of human and natural influences - science at the core of the DeCAdeS project. The talk sparked some interesting questions and discussion, with the students participating strongly. Audience feedback was that many of the attendees found the talk enjoyable and interesting. It's too soon to determine whether the talk influenced interest levels in related subjects (e.g. Geography/Physics). |
| Year(s) Of Engagement Activity | 2024 |
| URL | https://geography.org.uk/wp-content/uploads/2023/09/2023to202York4Programme1.pdf |