The US-UK Climate Consequences of Rapid Ocean Changes (CCROC) programme will take advantage of a decade of coincident observations from Rapid Climate Change (RAPID) and Overturning in the Subpolar North Atlantic Program (OSNAP) observing systems. This will deliver enhanced understanding of the AMOC and improve projections of future climate change throughout the North Atlantic region.
The programme will also deliver research to enable the future transformation of AMOC observations by taking advantage of alternative observing and modelling approaches in a way that will allow for a more sustainable and lower cost future AMOC observing system.
The CCROC programme’s aims will be delivered through six challenges. This funding opportunity will focus on challenges two to six. Information on challenge one can be found in the ‘additional info’ section.
Apply for funding to address one of the following challenges.
Challenge two: determining the heat and freshwater budgets of the North Atlantic Ocean using observations and models
Variations in the exchange of heat and freshwater between the ocean and atmosphere lead to changes in the circulation of both, and thus complex feedbacks in the redistribution of energy in the climate system.
This has important impacts both globally and regionally. For example, altering the rate at which the ocean absorbs excess heat from anthropogenic heating leading to changes in the rate of global surface warming, and by changing the prevalence of hurricanes and other weather systems.
The accuracy of forecasts of global surface temperature and regional climate change depend on the ability of climate models to correctly represent meridional heat and freshwater transport processes. Until now we have not had sufficient observations to assess this in models.
The challenge is to quantify the heat and freshwater budgets of the North Atlantic on interannual timescales for the full decade of overlapping RAPID and OSNAP observations (2014 to 2024) by using:
- ocean transport measurements in the subtropical (RAPID observations) and subpolar gyres (OSNAP observations)
- datasets of in-situ ocean temperature and salinity
- datasets of air-sea fluxes
Measurements of heat and freshwater convergence or divergence will also be used as a benchmark for climate models to determine which models best simulate transport processes in the North Atlantic. Leading to improved predictions and projections of the future AMOC and estimates of the likelihood of AMOC slowdown, or even collapse.
Proposals should seek to enhance the international collaboration to measure the basin scale transports of heat and freshwater by making use of the transport measurements from RAPID and OSNAP observing systems, along with other data, building on existing research.
Challenge three: using RAPID and OSNAP AMOC observations to establish the predictability of North Atlantic sector climate
AMOC has been shown to have important climate impacts on interannual timescales and longer. There is relatively little work on the prediction of variability and the assessment of AMOC predictability in state-of-the-art climate models. This is especially the case at seasonal timescales where the AMOC changes could have important impacts and predictions can be robustly assessed using RAPID and OSNAP AMOC observations.
Recent work on seasonal to decadal predictions have shown that atmospheric circulation is more predictable than previous thought, but signals need to be calibrated using observations to correct their magnitude.
Research is needed to determine if AMOC predictions and projections, and climate impacts, can be improved by taking advantage of properly calibrated atmospheric predictions and the predictability of the Ekman component.
The challenge is to assess AMOC predictions and projections, and climate impacts, in state-of-the-art climate models on a range of timescales from seasonal to interannual, to decadal.
Proposals will need to explore the mechanisms that lead to predictability and determine the extent to which AMOC predictions can be improved through calibration of predictions and the implications for wider climate. In addition, the question of the attribution of past AMOC changes to either internal or external variability should be addressed.
This challenge links to the World Climate Research Programme’s new lighthouse activity on explaining and predicting the Earth system which is tasked with exploring and expanding our capability to attribute and predict changes.
Challenge four: coastal and shelf sea level and AMOC
Coastal sea level change is an important way in which people experience the effects of variations in the deep ocean and such changes have the potential for significant socio-economic impacts.
There are major implications for climate mitigation and adaptation strategies associated with coastal sea level change. It is known that the AMOC impacts the coastal sea level of the eastern US coast, and there are also open ocean subpolar North Atlantic dynamic height associations with the changing AMOC.
New analysis of the relationship between OSNAP array and sea surface height shows positive correlation with subpolar shelf-seas sea level extending to the coast. This shows the potential for past, present, and future AMOC change to imprint on coastal and shelf sea level throughout the Atlantic.
Despite progress there is still a lack of understanding of how AMOC variability imprints on coastal and shelf sea level change throughout the Atlantic Ocean. There is also a lack of mechanistic understanding of what the effects might be, with the possible exception of the US eastern seaboard.
The challenge is:
- to develop a mechanistic understanding of how Atlantic coastal and shelf sea level will be impacted by a decreasing AMOC
- to unpick cause and effect
- to quantify AMOC related impact on regional sea level
This will be achieved through examining relationships between AMOC as observed by RAPID, OSNAP and measurements of sea level using Earth observation and in situ measurements. There is also a need to assess our confidence in regional and local model projections of sea level change through the new understanding gained.
Challenge five: monitoring the AMOC temporal and spatial evolution through indirect observations
The existing systems for observing the AMOC are complicated, expensive, and incomplete spatially and in terms of velocity and transport accuracy, as measurements are being made at a small number of locations in the Atlantic.
In addition, the observations only span a couple of decades at most, so there is no long-term AMOC time series on which to base understanding of decadal-to-centennial changes and their climatic impacts.
On longer timescales decadal-to-centennial proxies exist but need to be better understood because they are underpinned by model behaviour which may not fully capture the true AMOC behaviour.
Adjoint modelling has quantified the model AMOC sensitivity to regional wind and surface buoyancy fluxes, showing that AMOC can be reconstructed from the forcing over certain timescales, but this has not yet been tested in observations.
Previous investigations into using indirect measurements to observe AMOC change have been model-based and have shown that results are model-dependent. However, new analysis of four years of OSNAP data has found strong correlations between upper ocean density measured with profile data, satellite sea surface height and AMOC variability.
This gives support to the idea that indirect observations could be used to monitor long term AMOC change. With the availability of 20 years of RAPID and 10 years of OSNAP observations, now is the time to test this approach with real-world data.
The challenge is to define a new framework for monitoring the temporal and spatial evolution of the AMOC, and associated heat and freshwater transports, using existing Global Ocean Observing System (GOOS) observational networks. This will remove, or reduce, the need for complex and costly moored transport arrays.
Proposals will need to:
- test the new framework against the existing AMOC observations (RAPID, OSNAP) to verify that, at least for the timescales that direct observations are available, the indirect approach can reproduce the direct measurements to within acceptable error bounds
- produce recommendations for enhanced sampling in the GOOS networks to reduce the potential errors in pursing this approach
- use the approach to extend the AMOC record backwards in time using historic data
Any proposed approach must both have data available going back in time for a sufficiently long period and be sustainable going forward into the future.
This challenge is based on the hypothesis that the interannual and longer temporal variability of AMOC heat transport has a multi-parameter ocean or atmosphere signature and sensitivity to forcing that is different in each meridional zone (Nordic, subpolar, subtropics).
This could be exploited to estimate the time varying AMOC using indirect observations of the relevant parameters.
Challenge six: enhanced understanding of carbon accumulation in the North Atlantic by combining models and ocean transport observations.
The ocean is the largest dynamic reservoir of carbon in the Earth system, and the North Atlantic is a key sink for anthropogenic carbon. The accumulation of anthropogenic carbon in the North Atlantic is strongly linked to the AMOC, which is highly variable and predicted to decline during the 21st century as the Earth warms.
The upper limb of the AMOC transports nutrients to the subpolar gyre and the slowing of the AMOC may impact the currently highly productive waters and the intense biological carbon uptake there.
Absorption of carbon dioxide in seawater is decreasing pH and reducing the ability of many organisms to grow calcium carbonate shells. These ocean acidification impacts are conveyed to the deep ocean by the AMOC, endangering cold-water coral habitats.
Quantifying the uptake of carbon by the North Atlantic serves as a major constraint on the uncertain northern hemisphere land sink. The terrestrial biosphere sink for anthropogenic carbon is of a similar magnitude to the ocean sink but has large uncertainties and so is quantified as the residual of total emissions and the changes in ocean and atmospheric carbon inventories.
Consequently, understanding the magnitude and likely future trend in North Atlantic carbon accumulation in response to changing ocean circulation and atmospheric conditions is crucial for determining:
- the fate of global carbon stocks, both in the ocean and in the wider Earth system
- the impacts on North Atlantic ecosystems
This challenge will seek to estimate anthropogenic carbon transport, uptake and storage in the North Atlantic. This will be done by combining AMOC transport observations with hydrographic carbon data and air-sea fluxes to provide an improved understanding of changes in anthropogenic carbon accumulation in the basin.
Proposals should seek to exploit the RAPID and OSNAP AMOC measurements to obtain improved estimates of changes in anthropogenic carbon accumulation in the North Atlantic, together with a measure of the uncertainties in those estimates.
The results should be compared to climate model results for changes in anthropogenic carbon transports, uptake and accumulation, in order to assess our ability to obtain accurate predictions and projections for future carbon uptake and accumulation in the North Atlantic.
Through the delivery of the programme’s challenges, the outcomes of this programme will:
- determine the controls on the heat and freshwater budgets of the North Atlantic Ocean by combining longer term (more than five years) observations of the AMOC with ocean climate models
- understand the role of AMOC in seasonal to interannual climate predictability, leading to improved predictive capability from models
- determine how the AMOC impacts circum-Atlantic changes in sea level
- determine the feasibility of using indirect measurements to monitor the AMOC
- provide an improved understanding of the accumulation of anthropogenic carbon in the North Atlantic
- provide an appraisal of transformational observation and modelling approaches that will allow for North Atlantic observations to be sustained at much reduced cost
- deliver an implementation plan to enable the transformation of the current configuration of the UK-US RAPID observing system to a more sustainable, lower cost, system for AMOC observations by the end of current US-UK funding in 2026 to 2027
Apply for funding
This funding opportunity is focused on challenges two to six. Apply for funding to address one of these challenges.
All projects must be collaborative and include UK and US scientists. One integrated proposal should be submitted to NERC detailing both the UK and US contributions to the project.
Proposals addressing challenges three, four and five are encouraged to consider engaging with the UK’s Met Office Hadley Centre on a Project Partner basis. Potential in-kind contributions from the Met Office Hadley Centre are outlined in the ‘additional info’ section.
Projects will be required to provide progress reports to the CCROC Programme Advisory Group twice a year and attend review meetings. Meetings will be held virtually.
The travel and subsistence costs for three members of the project team to attend a programme science meeting in person must be included in proposals.
Proposals must start no later than 10 November 2023 and must finish by 31 March 2026. Successful proposals will not be able to apply for no cost extensions and should therefore consider carefully the time required for any recruitment activity and factor this into workplans for proposals.
The FEC for a project will be up to £625,000 for the UK component. NERC will fund 80% of FEC for most UK costs, with some exceptions (see ‘what we will not fund’ heading). The US component or proposals will be funded under the lead agency agreement and costs will be limited to $625,000 per project.
Up to four projects will be funded. One project will be funded to address challenge six. It is possible that one or more of these challenges will not be addressed by successful proposals. One proposal will be funded to address challenge three. If a challenge three proposal is not recommended for funding by the assessment panel, the funders may decide to fund a third project addressing challenges two, four or five.
We will fund 80% of the FEC for UK organisations:
- directly incurred costs such as staff payroll, travel and subsistence, and consumables
- directly allocated costs such as investigators’ salaries, estates costs and shared resources
- indirect costs such as research organisation administration
UK equipment is funded at 50% FEC.
Eligible international co-investigator costs (under the International Institute for Applied Systems Analysis or Norway agreement) are funded at:
- 100% for eligible direct costs
- a maximum of 30% of the FEC value can be requested for all international costs
For eligible international co-investigators, we will fund:
- co-investigator salaries
- directly incurred (DI) costs (for example, travel and subsistence, consumables)
- research assistants
What we will not fund
For eligible international co-investigators we will not fund:
- estates and other indirect costs
- capital costs
- equipment over £10,000 (anything under £10,000 can be requested under DI costs)
NERC services and facilities
Proposals should include formal requests for NERC services and facilities (for example, high-performance computing (HPC) or isotope analyses) where relevant. No NERC ship-time or support from the National Marine Facilities is available for the UK component of funded projects.
No additional funding is available to cover NERC services and facilities costs. Therefore, all costs associated with the use of NERC services and facilities must be included within:
- the funding limit of proposals
- the directly incurred other costs of proposals
Prior to submitting a proposal, applicants wishing to use a NERC service or facility must contact the facility to seek agreement that they could provide the service required.
If you wish to use most NERC facilities you will need to submit a mandatory ‘technical assessment’ with your proposal. This technical assessment is required for aircraft but not for HPC. For NERC, this means a quote for the work which the facility will provide.
A full list of the facilities requiring this quote can be found on the NERC website. Further information on NERC services and facilities can be found on the NERC website.
For NERC-relevant data, you must adhere to the NERC data policy. You should produce an outline data management plan as part of your proposal.
NERC will pay the data centre directly on behalf of your programme for archival and curation services. However, you should ensure that you request sufficient resources to cover preparation of data for archiving by the research team.
Read the NERC data policy.