UK-OSNAP-Decade: 10 years of observing and understanding the overturning circulation in the subpolar North Atlantic (2014-2024)
Lead Research Organisation:
Scottish Association For Marine Science
Department Name: Contracts Office
Abstract
There is mounting evidence from measurements and models of the importance of the transports of heat and freshwater by the Subpolar North Atlantic Ocean. They impact on North Atlantic, European and global climate via temperature, precipitation and wind strength, and also on marine ecosystems, hurricanes, even rainfall in the Sahel, the Amazon and parts of the US. The subpolar North Atlantic behaves substantially differently from the subtropical North Atlantic circulation, and their mechanisms and timescales for transport and storage of heat and freshwater are very different. Prior to 2014 the subpolar North Atlantic was inadequately measured, and it is still the case that no ocean general circulation or climate model represents it accurately.
UK-OSNAP-Decade aims to generate new knowledge and understanding of the subpolar North Atlantic to improve predictions of the contribution of the region to climate, by building on the successes of NERC Large Grant UK OSNAP, and as a contribution to the international collaborative project OSNAP (Overturning in the Subpolar North Atlantic Programme). We propose a programme of sustained observation of subpolar North Atlantic circulation and fluxes; a UK contribution to an international trans-basin, full-depth ocean observation array.
UK-OSNAP-Decade aims to generate new knowledge and understanding of the subpolar North Atlantic to improve predictions of the contribution of the region to climate, by building on the successes of NERC Large Grant UK OSNAP, and as a contribution to the international collaborative project OSNAP (Overturning in the Subpolar North Atlantic Programme). We propose a programme of sustained observation of subpolar North Atlantic circulation and fluxes; a UK contribution to an international trans-basin, full-depth ocean observation array.
Planned Impact
The UK-OSNAP-Decade data and results will benefit the National Capability programme CLASS (Climate Linked Atlantic Sector Science) by providing additional information about the warm water pathways in the eastern subpolar North Atlantic, including their heat and salt transport and water mass transformation.
The results from OSNAP will feed into national and international climate assessments including the UK Marine Climate Change Impacts Partnership (MCCIP), the International Council for the Exploration of the Seas (ICES) Annual Report on Ocean Climate, and of course the Intergovernmental Panel for Climate Change (IPCC) Assessment Reports.
The results will underpin EU FP7 programmes including Blue-Action, Atlas and iAtlantic, and contribute to the Global Ocean Observing System (GOOS) as an OceanSites observatory. It is also a contribution to an all-Atlantic observing system.
The results from OSNAP will feed into national and international climate assessments including the UK Marine Climate Change Impacts Partnership (MCCIP), the International Council for the Exploration of the Seas (ICES) Annual Report on Ocean Climate, and of course the Intergovernmental Panel for Climate Change (IPCC) Assessment Reports.
The results will underpin EU FP7 programmes including Blue-Action, Atlas and iAtlantic, and contribute to the Global Ocean Observing System (GOOS) as an OceanSites observatory. It is also a contribution to an all-Atlantic observing system.
Publications
Berx B
(2021)
Climate-Relevant Ocean Transport Measurements in the Atlantic and Arctic Oceans
in Oceanography
Fraser N
(2022)
North Atlantic Current and European Slope Current Circulation in the Rockall Trough Observed Using Moorings and Gliders
in Journal of Geophysical Research: Oceans
Fraser, N.J.
(2021)
120 years of AMOC variability reconstructed from observations using the Bernoulli inverse
in Geophysical Research Letters
Gary SF
(2020)
Larval behaviour, dispersal and population connectivity in the deep sea.
in Scientific reports
Houpert L
(2020)
Observed Variability of the North Atlantic Current in the Rockall Trough From 4 Years of Mooring Measurements
in Journal of Geophysical Research: Oceans
Huthnance J
(2020)
Oceanic Density/Pressure Gradients and Slope Currents
in Journal of Physical Oceanography
Huthnance J
(2022)
Ocean shelf exchange, NW European shelf seas: Measurements, estimates and comparisons
in Progress in Oceanography
Jones S
(2020)
Storm-driven across-shelf oceanic flows into coastal waters
in Ocean Science
| Title | Animation of robotic glider occupation of the eastern OSNAP line |
| Description | Animation of robotic glider occupation of the eastern OSNAP line. Led to coverage by BBC Scotland (see separate entry) |
| Type Of Art | Film/Video/Animation |
| Year Produced | 2022 |
| Impact | Improved public understanding of OSNAP ocean monitoring |
| Title | Animation of the DY120 cruise track, showing weather conditions encountered during cruise |
| Description | Animation of the DY120 cruise track, showing weather conditions encountered during cruise. Also illustrating SAMS robotic glider occupying Ellett Array. |
| Type Of Art | Artefact (including digital) |
| Year Produced | 2020 |
| Impact | Reached a large scientific and non-scientific audience. The combination of COVID challenges, the constant threat of adverse weather and a successful conclusion in the face of these challenges made for a compelling story. Initially shared through Twitter, later added to Youtube. |
| URL | https://www.youtube.com/watch?v=KRwmWWIIvDs&feature=emb_imp_woyt |
| Description | Understanding and predicting climate change is the pre-eminent scientific problem for the 21st Century. The Atlantic Meridional Overturning Circulation (AMOC) is influential for European Climate at a fundamental level. One of the key IPCC AR6 forecasts is that the Atlantic Meridional Overturning Circulation (AMOC) will continue slowing over the 21st century (> 90 % likelihood). However, it only reports medium confidence that the AMOC will not pass a tipping point causing abrupt shifts in regional weather patterns, hydrological cycles and structural changes in UK agriculture and food security (Benton 2020; Ritchie et al. 2020). Thus, the trajectory and rate of AMOC change in the 21st century, which the Ellett Array monitors as part of the trans-Atlantic OSNAP array, is a central climate question that will have direct impacts on strategies for mitigation and adaption to climate change within the UK. This programme has made the first purposefully designed continuous observations of the AMOC in the subpolar North Atlantic. A series of high impact papers has defined the base state of the AMOC in this region and proposed new paradigmns for the functioning of the AMOC. This has led to a sustained reappraisal of how the AMOC functions in the North Atlantic, and thus how global warming may impact it in the future. |
| Exploitation Route | Continuing climate assesments; climate model evaluation; improved understanding of ocean physical processes and thus may lead to more optimal observational strategies. |
| Sectors | Agriculture, Food and Drink,Education,Environment,Leisure Activities, including Sports, Recreation and Tourism,Culture, Heritage, Museums and Collections,Transport |
| Description | IPCC 2021 states that the Atlantic Meridional Overturning Circulation (AMOC) will continue slowing over the 21st century (> 90 % likelihood). However, it only reports medium confidence that the AMOC will not pass a tipping point causing abrupt shifts in regional weather patterns, hydrological cycles and structural changes in UK agriculture and food security (Benton 2020; Ritchie et al. 2020). Thus, the trajectory and rate of AMOC change in the 21st century, which the Ellett Array monitors as part of the trans-Atlantic OSNAP array, is a central climate question that will have direct impacts on strategies for mitigation and adaption to climate change within the UK. |
| First Year Of Impact | 2017 |
| Sector | Agriculture, Food and Drink,Education,Environment,Culture, Heritage, Museums and Collections |
| Impact Types | Societal,Policy & public services |
| Description | UK-OSNAP-Decade: 10 years of observing and understanding the overturning circulation in the subpolar North Atlantic (2014-2024) |
| Amount | £100,000 (GBP) |
| Funding ID | NE/T008938/1 |
| Organisation | Natural Environment Research Council |
| Sector | Public |
| Country | United Kingdom |
| Start | 10/2023 |
| End | 04/2025 |
| Title | Contribution to IAPSO best practice group for moored CTD instruments |
| Description | Contribution to IAPSO best practice group for moored CTD instruments. Assessing calibration methods for moored CTDs with the aim of establishing an international standard for mooring calibration. |
| Type Of Material | Improvements to research infrastructure |
| Year Produced | 2021 |
| Provided To Others? | Yes |
| Impact | -'Lessons learned' shared between projects and institutions -'Best practice' methods established -Greater standardisation of practice between institutions and projects |
| Title | Github glider processing toolbox |
| Description | Created a toolbox on Github to manage glider processing toolbox in a collaborative fashion. |
| Type Of Material | Improvements to research infrastructure |
| Year Produced | 2021 |
| Provided To Others? | Yes |
| Impact | Improved collaboration on glider processing techniques, increased impact of glider data |
| Title | Github mooring processing toolbox |
| Description | Created a toolbox on Github to manage the OSNAP mooring processing and transport calculation programming code. |
| Type Of Material | Improvements to research infrastructure |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| Impact | Improvements for collaboration and standardisation with the international mooring community |
| Title | Code used in Fox et al 2022. "Exceptional freshening and cooling in the eastern subpolar North Atlantic caused by reduced Labrador Sea surface heat loss" |
| Description | Fox, A. D., Rath, W., and Schmidt, C.: Code used in Fox et al 2022. "Exceptional freshening and cooling in the eastern subpolar North Atlantic caused by reduced Labrador Sea surface heat loss", Zenodo [code], https://doi.org/10.5281/zenodo.6393656, 2022 |
| Type Of Material | Data analysis technique |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| Impact | Improved understanding of the causes of the 2016 freshening event in the Eastern Atlantic |
| Title | Code used in transport and flux analysis for Jones et al. 2023. "Observation-based estimates of volume, heat and freshwater exchanges between the subpolar North Atlantic interior, its boundary currents and the atmosphere" |
| Description | Code used in transport and flux analysis for Jones et al. 2023. "Observation-based estimates of volume, heat and freshwater exchanges between the subpolar North Atlantic interior, its boundary currents and the atmosphere" |
| Type Of Material | Data analysis technique |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| Impact | Improved characterisation of fluxes into and out of the North Atlantic Subpolar Gyre |
| Title | OSNAP Rockall Trough transport time series |
| Description | The Rockall Trough mooring array consists of five moorings with the following objectives: Rockall Trough Western Boundary 1 (RTWB1) & Rockall Trough Eastern Boundary 1 (RTEB1) are end-point density moorings measuring the baroclinic circulation across the width of the Rockall Trough using CTDs distributed in the vertical; RTWB1 & RTWB2 measure the Wyville-Thomson Ridge overflow current along the Feni Ridge using current meters; RTEB1 measures the Shelf Edge Current using current meters. RTWB1 and RTEB1 include bottom pressure recorders to determine the barotropic variability across the Rockall Trough. The Rockall Trough section is also surveyed by glider, now used to measure the slope current east of EB1. This timeseries of volume, heat and salt transport through the Rockall Trough is calculated from the mooring data using the method of Houpert et al. (2018). Houpert, L., Inall, M. E., Dumont, E., Gary, S., Johnson, C., Porter, M., et al. (2018). Structure and transport of the north atlantic current in the Eastern Subpolar Gyre from sustained glider observations. Journal of Geophysical Research: Oceans, 123, 6019- 6038. https://doi.org/10.1029/2018JC014162 |
| Type Of Material | Database/Collection of data |
| Year Produced | 2021 |
| Provided To Others? | Yes |
| Impact | Simple access to key measures of fluxes through the Rockall Trough for scientists from a range of disciplines. |
| URL | https://thredds.sams.ac.uk/thredds/catalog/osnap/catalog.html?dataset=osnap/Rockall-Trough-Transport... |
| Title | OSNAP gridded Rockall Trough mooring time series |
| Description | The Rockall Trough mooring array consists of five moorings with the following objectives: Rockall Trough Western Boundary 1 (RTWB1) & Rockall Trough Eastern Boundary 1 (RTEB1) are end-point density moorings measuring the baroclinic circulation across the width of the Rockall Trough using CTDs distributed in the vertical; RTWB1 & RTWB2 measure the Wyville-Thomson Ridge overflow current along the Feni Ridge using current meters; RTEB1 measures the Shelf Edge Current using current meters. RTWB1 and RTEB1 include bottom pressure recorders to determine the barotropic variability across the Rockall Trough. The Rockall Trough section is also surveyed by glider, now used to measure the slope current east of EB1. The gridded timeseries presented here are quality controlled and science-ready data products generated from the individual moorings. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2021 |
| Provided To Others? | Yes |
| Impact | Ease of access to OSNAP Rockall Trough data for scientist from a range of disciplines, broadening its user base. |
| URL | https://thredds.sams.ac.uk/thredds/catalog/osnap/catalog.html?dataset=osnap/Rockall-Trough-Mooring-T... |
| Title | Subpolar gyre boundary dataset |
| Description | Subpolar gyre boundary dataset - A climatology of historical profile data optimised for the investigation of water properties around the boundary of the subpolar gyre. |
| Type Of Material | Data analysis technique |
| Year Produced | 2020 |
| Provided To Others? | No |
| Impact | Circulation at the boundary of the subpolar North Atlantic influences both the horizontal (gyre) and vertical (overturning) components of the flow structure. While boundary current transport projects directly onto subpolar gyre strength, recent modelling studies have highlighted that buoyancy fluxes between the basin interior and the boundary, followed by rapid buoyancy export by boundary currents, are crucial steps in projecting air-sea interaction onto the strength of the Atlantic Meridional Overturning Circulation (AMOC). This work seeks observational insights into these key boundary processes. To achieve this, we have constructed a robust boundary climatology from quality controlled CTD and Argo hydrography since the turn of the millennium. Following the 1000 m isobath north of 47 °N and aggregating data into 100 km bins, we build a picture of the typical large-scale temperature and salinity structure for each month. This product will allow us to identify where and when important interior-boundary buoyancy fluxes take place over a seasonal cycle. A first step is to evaluate geostrophic flow into the boundary, and hence describe the vertical structure of advective buoyancy exchange. By appealing to satellite altimetry and Argo trajectories, we can also estimate turbulent eddy fluxes both at the surface and 1000 m depth. Models indicate these parameters are key in dictating the pathways for the AMOC lower limb, and we will place our observational findings in the context of these results. Boundary current strength is another key parameter dictating the export of dense water from the subpolar gyre. We will appeal to satellite altimetry to build corresponding climatologies for barotropic boundary flow. Furthermore, along-slope density gradients give rise to a baroclinic boundary current forcing term, which we aim to investigate here. Water density generally increases as we follow the gyre counter-clockwise, with the notable exception of the West Greenland Current section, and our product allows us to partition the spatially-varying contribution of temperature and salinity towards these density gradients. For example, we can evaluate the impact of cooling along the eastern boundary, or surface freshening around southern Greenland, on the dynamics of boundary flow. Ultimately, we would like to understand the evolution of the dynamical balance experienced by a hypothetical fluid parcel traversing the entire subpolar gyre. |
| Title | Trajectories used in "Exceptional freshening and cooling in the eastern subpolar North Atlantic caused by reduced Labrador Sea surface heat loss" |
| Description | Fox, A. D., Rath, W., and Schmidt, C.: Trajectories used in "Exceptional freshening and cooling in the eastern subpolar North Atlantic caused by reduced Labrador Sea surface heat loss", GEOMAR Helmholtz Centre for Ocean Research Kiel [distributor] [dataset], https://hdl.handle.net/20.500.12085/830c72af-b5ca-44ac-8357-3173392f402b, 2022 |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| Impact | New understanding of the causes of the 2016 freshening event in the North-Eastern Atlantic. |
| URL | https://hdl.handle.net/20.500.12085/830c72af-b5ca-44ac-8357-3173392f402b |
| Description | ICES expert working group on Oceanic Hydrography (WGOH) |
| Organisation | International Council for the Exploration of the Sea (ICES) |
| Country | Denmark |
| Sector | Charity/Non Profit |
| PI Contribution | Intellectual input, access to datasets, professional recommendations |
| Collaborator Contribution | As above |
| Impact | ICES. 2021. Working Group on Oceanic Hydrography (WGOH; outputs from 2020 meeting). ICES Scientific Reports. 3:91. 12 pp. https://doi.org/10.17895/ices.pub.8562 |
| Start Year | 2018 |
| Description | Advise and coordination for ATLAS visualisations for Dynamic Earth, for COP26 conference |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | Participation in the team developing ATLAS visualisation, showcasing research output. |
| Year(s) Of Engagement Activity | 2021 |
| Description | Blog posts during OSNAP DY120 cruise |
| Form Of Engagement Activity | Engagement focused website, blog or social media channel |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | A series of blog posts during OSNAP DY120 cruise in October 2020, covering the challenges of mobilising during COVID, the science work taking place and the historical context to the cruise. Widely shared. |
| Year(s) Of Engagement Activity | 2020 |
| URL | https://projects.noc.ac.uk/class-project/blog |
| Description | Double page newspaper article on OSNAP DY120 cruise and historical context |
| Form Of Engagement Activity | A magazine, newsletter or online publication |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Public/other audiences |
| Results and Impact | Double page newspaper article on OSNAP DY120 cruise and historical context, in Oban Times. Particularly relevant for the region as the cruise ended with RRS Discovery dropping scientists at SAMS in Oban, allowing local residents a rare chance to see a large research vessel up close. |
| Year(s) Of Engagement Activity | 2020 |
| URL | https://www.obantimes.co.uk/2020/10/27/cruise-ship-returns-with-vital-climate-change-data/ |
| Description | Dynamic Earth 'Meet the Scientists' open day as part of COP26 |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Public/other audiences |
| Results and Impact | Dynamic Earth 'meet the scientists' outreach event to coincide with COP26. Reached around 1500 people. |
| Year(s) Of Engagement Activity | 2021 |
| Description | Interview for BBC Scotland evening news |
| Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Public/other audiences |
| Results and Impact | Interview and animation on robotic underwater gliders. News segment on BBC Scotland radio 3rd Feb 2022, BBC Scotland evening news on 4th Feb 2022 with several staff members interviewed. |
| Year(s) Of Engagement Activity | 2021 |
| Description | POGO workshop: Best Practises in biogeochemical ocean observation: instrumentation, operation and quality control. |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | POGO workshop, SAMS, 15th-17th June 2022. 14 international collaborators, 30 international participants |
| Year(s) Of Engagement Activity | 2022 |
| Description | Public lecture, Royal Society of Edinburgh |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Public/other audiences |
| Results and Impact | Public lecture, Royal Society of Edinburgh entitled "Climate Change and COP26". |
| Year(s) Of Engagement Activity | 2021 |
| Description | School visit |
| Form Of Engagement Activity | Participation in an open day or visit at my research institution |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Schools |
| Results and Impact | Demonstrator for school visit, approximately 40 pupils attended. |
| Year(s) Of Engagement Activity | 2022 |
| Description | School visit (Lochaber High School) |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Schools |
| Results and Impact | Neil Fraser spoke to two different year groups at Lochaber High School about SAMS' ocean physics research. These sessions were organized by one of the maths teachers and centered were aimed at showing career opportunities in mathematics and related subjects. |
| Year(s) Of Engagement Activity | 2021 |
| Description | Talk at COP26 cryosphere pavilion in Glasgow |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Policymakers/politicians |
| Results and Impact | Talk / livestream at the cryosphere pavilion during COP26, Glasgow October 2021. |
| Year(s) Of Engagement Activity | 2021 |