ENCORE is the National Capability ORchestra Extension (ENCORE)

Lead Research Organisation: National Oceanography Centre
Department Name: Science and Technology

Abstract

Climate change is one of the most urgent issues facing humanity and life on Earth. Better predictions of future climate change are needed, so that measures to reduce its impact and cope with its effects can be put in place. However, improving these predictions requires better knowledge of how the global climate system functions, and this knowledge is currently incomplete. A critical gap concerns understanding of the uptake of heat and carbon by the oceans. Over 90% of the extra heat now present in the Earth System because of global warming has entered the ocean, with strong increases in both the upper and deep ocean apparent since the 1970s. Further, the global ocean is the largest reservoir of carbon in the climate system, and has absorbed nearly one-third of the extra carbon emissions produced since the industrial revolution. Climate change in the atmosphere is strongly moderated by these processes, and would be dramatically greater without them.

The Southern Ocean - the vast ocean that encircles Antarctica - is critically important in this regard. Because of the nature of its circulation, its physical and chemical properties, and its connections with the rest of the globe, it accounts for around half of the oceanic uptake of carbon, and around three-quarters of the heat uptake. However, because of its remoteness and hostile environment, with stormy seas, heavy sea ice in places, and long periods of darkness in winter, the Southern Ocean is also the least-measured and least-understood ocean in the world. One consequence of this lack of understanding is that the representations of the Southern Ocean in many of the models used to create future climate projections are not fit for purpose.

Our project, ENCORE is the National Capability ORchestra Extension (ENCORE) extends the original Ocean Regulation of Climate by Heat and Carbon Sequestration and Transports (ORCHESTRA) by a year. It represents a linking together of many of the major environmental research institutes in the UK, who will work with national and international partners to address these issues. We will carry on our unique combination of data collection, novel analyses and computer simulations to radically improve our ability to measure, understand and predict the circulation and role in global climate of the Southern Ocean. In the single field season available to us data collection will include three cruise elements continuing our long term monitoring of the Atlantic sector of the Southern Ocean to determine the basin-scale transports of heat and carbon in all the different ocean layers (near-surface, intermediate, abyssal). It will also carry on flights with research aircraft to determine climatically-important transfers of heat and carbon between the atmosphere and ocean in all different conditions of sea ice. Information gathered by previous such field work will continue to be examined, producing new insights into ocean processes and improvements to ocean models. An important element of ENCORE will be the synthesis of the new information and understanding gathered over the ORCHESTRA period both with itself and with complimentary parallel projects such as RoSES, SOCCOM and SO-CHIC. This synthesis will produce a holistic understanding of the Atlantic sector and wider Southern Ocean's impact on global climate, and how it may change in the future. ENCORE will work closely with the Met Office in particular to see that such understanding is pulled through to examine the ability of the HadGEM and other UK climate models to replicate the complex dynamics of the region, and to suggest improvements to future iterations of these models.

Publications

10 25 50
 
Description This is a large and wide ranging project. It is the extension of the ORCHESTRA project and directly continues much of the work and outputs noted there. Notable discoveries and achievements include: New measurements of the exchange of CO2 between the atmosphere and ocean from autonomous measurement systems installed aboard the RRS James Clark Ross and Discovery have contributed to a large increase in CO2 exchange measurements in the Southern Ocean - an extremely data sparse region. These are complimented by numerous aircraft datasets collected on board the BAS MASIN aircraft, carrying NOC flux instrumentation. During the ENCORE period additional flights were made over the Weddell Sea during unusual ice conditions, collecting a novel dataset that is undergoing analysis at present. A python software package for calculating air-sea fluxes from meteorological observations using a variety of parameterisations from the literature will be made publicly available via gitlab and described by a paper in the journal Frontiers in Marine Science. As part of the development of the software package many different options for the flux calculation methodology were tested and showing that some of the methodological choices could introduce differences in the fluxes that are substantially outside the uncertainty range for climate applications. The application of unsupervised clustering, a machine learning technique, to collated Weddell Gyre data has been used to identify spatially coherent thermohaline domains. The data include shipped-based CTDs, seal tag and Argo float profiles. Despite the analysis excluding geographic (longitude & latitude) information, it consistently identified region in the Antarctic Circumpolar Current, central Weddell Gyre and the Antarctic Slope current. Potential signatures of Weddell Deep Water inflow and export pathways of Antarctic Bottom water was also identified. Combining adjoint model sensitivities with CMIP model spread has been used to identify types of forcing and geographic regions that may contribute to the inter-model spread. Inter-model uncertainty in zonal wind stress and SST were found to have the largest impacts on mode water formation region heat content. A combination of EM-APEX float data and a 75 day glider deployment were used to make targeted observations of Discover Bank in early 2019. The EM-APEX data was QC'd and analysed as part of ENCORE. CTD, ADCP and float data all demonstrated the circulation to be consistent with the presence of Taylor column-like structures over the Bank. These structures can retain water over seamounts for long periods. Ongoing analysis is focusing on the relative contributions of these particular locations compared to the large-scale circulation structure in mediating exchange between the Weddell Gyre and Antarctic Circumpolar Current. ECCOv4 adjoint sensitivities were used to devise a pattern of zonal wind stress perturbation that might be expected to semi-optimally perturb the heat content of the ORCHESTRA box. Experiments were then performed with these perturbations in the NEMO-based 1/12o model as part of the ORCHESTRA project. Under ENCORE, analysis of these experiments has taken place and the ECCOv4 forwards model has been used to run equivalent experiments at lower resolution. Analysis has shown that the two models have broadly similar responses to the wind stress change. The magnitude and direction (increase/decrease) of the heat content change in the ORCHESTRA box is very close, as is the distribution through space. This change is largely brought about by changes in the current structure on the eastern boundary of the box, with closed budgets in the ECCOv4 forwards model confirming that at scales >15 years, the advective change is balanced by surface heat flux change. Both models indicate that the mean temperature of the ORCHESTRA box increase/decreases at the expense of the rest of the ocean, with the heat being redistributed by the ocean circulation, rather than added/removed by surface heat fluxes A new methodology of estimating mixed layer budgets in models and observations Sanders et al., (in prep) finds that SAMW formation regions, particularly the eastern most Pacific pools, are susceptible to influence from changes in Ross Sea sea ice production and export. They show that periods of particularly high ice melt on the northern edge of the Ross or Amundsen-Bellingshausen sea can produce an excess of freshwater which is transported to the SAMW formation regions and acts to stabilise them. This in turn often aligns with stronger positive buoyancy forcing, leading to anomalously shallow winter mixed layers and consequently weaker SAMW export. Sanders et al., also link such events to the anomalous year 2016 when mixed layer depths reached an all time low in the South East Pacific. Dense Weddell Sea Bottom Water (WSBW) exported from the Weddell Sea contributes to the Antarctic Bottom Water that circulates throughout the global abyssal ocean in the lower limb of the Meridional Overturning Circulation (MOC). ENCORE work (Zhou et al, in prep), in collaboration with SO-CHIC and SO-ICE (EU funded projects) has shown that the volume of this key water mass has shrunk by ~30% over the last 30 years. In turn, this work demonstrates that this is likely due to reduced ice free areas (polynyas) during winter in front of the Ronne-Filchner ice shelf, itself driven by shifts in the prevailing wind patterns. The above regional analysis is complimented by the analysis of the whole Southern Ocean in CMIP6. This work (Meijers et al, in prep) shows that AABW volumes are projected to decline by up to 50% on average to 2100 under strong climate forcing scenarios. This is largely due to changes in surface buoyancy fluxes, increasing surface stratification and the cessation of deep convection around Antarctica in many climate models. Analysis of the representation of the mixed layer in setting the uptake of heat and carbon by the overturning circulation is also ongoing (Sivankutty et al, in prep), and it has been shown that on average all models experience a schoaling mixed layer and increased stratificiation over much of the ocean in response to climate forcing. This CMIP modelling work is also supporting the RoSES project SARDINE, which seeks to contextualise Southern Ocean change in relation to global climate sensitivities. A two box inversion based on ORCHESTRA/ENCORE hydorgraphic data has been constructed. This work is ongoing, but will form the basis for comparisons with similar estimates made in ~2010.
Exploitation Route The datasets generated in ORCHESTRA/ENCORE are key benchmarks that will enable ongoing variability and change to be understood and better predicted. They, and the outputs of the ORCHESTRA/ENCORE modelling activities, will feed into the IPCC process (notably development of CMIP7 class models) via the JMMP and MetOffice and hence will influence the advice given to governments and policy makers. As key National Capability outputs, ORCHESTRA/ENCORE results, models and data products act to underpin or compliment numerous UK and international research efforts. These include RoSES, SARDINE, SOCCOM, SO-CHIC, SO-ICE, SO-FINE, SOOS, TiPPACS and many other projects. Newly funded projects, notably DEFIANT, BIOPOLE and CANARi (NERC) and SO-ICE, OCEAN:ICE (EU) build strongly on aspects of ORCHESTRA outputs. Similarly software developed or deployed by ORCHESTRA/ENCORE, such as the new Pangeo deployment on CEDA, AirSeaFluxCode foundational bulk formula code, and Argo objective mappings, will be widely used by the scientific community both during the project lifetime and beyond. They also have directly contributed to high impact policy documents, for example; acting to inform the recently released IPCC Special Report on the Oceans and Cryosphere and the COP26 meeting. ORCHESTRA/ENCORE activities are also influencing educational materials (undergraduate textbooks, books for general readership, videos, outreach materials), which will help formulate the importance of ocean and climate science in the minds of the public and those undertaking education. ORCHESTRA/ENCORE research and scientists have achieved considerable media exposure and public outreach activities, including newspaper columns, numerous TV and radio interviews, coordinating science festival activities, public science days (e.g. launch/first sailing of the RRS SDA) and school talks.
Sectors Energy,Environment,Government, Democracy and Justice

URL https://orchestra.ac.uk/encore/
 
Description ENCORE is the extension of the ORCHESTRA project and directly continues much of the work and outputs noted there. The ORCHESTRA/ENCORE findings have fed into briefings given to a wide range of stakeholders. This has included: • Government ministers • MPs • IPCC Assessment Report 6 and the Special Report on Oceans and Cryosphere • Officials from government departments and agencies (including presentations to BEIS) • Government officials from overseas (including Mayors from Guangdong province, China) • International organisations (including European Bank for Reconstruction and Development and World Bank) • COP26 • Commission for the Conservation of Antarctic Marine Living Resources • Southern Ocean Observing System (including marine observation system planning) • Regulatory authorities (including Prudential Regulation Authority and European Insurance and Occupational Pensions Authority) • Business (including Jaguar Land Rover, Vestas 11th Hour Racing, Network Rail, Saint Gobain, BNP Paribas, Tata, Pinsent Masons) • Business conferences (including Business Green, European Renewables) • Students and researchers from other disciplines (BP Institute Masterclass, Leverhulme Climate Justice project, Chemical Engineering Dept, Cambridge) • Media professionals (Sheffield Documentary Festival) • The public (Cambridge Science Festival, Ely Science Festival, TEDx talk) • Community groups and membership organisations (Women's Institute, U3A), school visits (University of Cambridge Primary School, St Matthew's Primary School, Stephen Perse Foundation, St Albans High School for Girls). • Specific outputs have included policy briefings (CISL briefing on climate and financial risk), online magazine articles, newspaper articles, television and radio interviews, and taught courses (ESA MOOC, Masters in Sustainability, Professional Certificate in Sustainable Business, Professional Certificate in Sustainable Value Chains); leadership of the Intergovernmental Panel on Climate Change's Special Report on Oceans and the Cryosphere.
First Year Of Impact 2021
Sector Education,Environment,Government, Democracy and Justice,Manufacturing, including Industrial Biotechology
Impact Types Cultural,Societal,Economic,Policy & public services

 
Title 1/12o model data in process of being archived 
Description 1/12o model data in process of being archived: JRA55FIL-ORCH0083-LIM3, time-filtered forcing to eliminate high frequency forcing, and JRA55WP3-ORCH0083-LIM3, ECCOv4-inspired wind stress perturbations to semi-optimally perturb the heat content of the ORCHESTRA box. This output is also included in the main award (NE/V013254/1) report, publication ID 622f4883c13185.64457463 
Type Of Material Data handling & control 
Year Produced 2021 
Provided To Others? No  
Impact 1/12o model data in process of being archived: JRA55FIL-ORCH0083-LIM3, time-filtered forcing to eliminate high frequency forcing, and JRA55WP3-ORCH0083-LIM3, ECCOv4-inspired wind stress perturbations to semi-optimally perturb the heat content of the ORCHESTRA box. 
 
Title Model data archived: CORE2NYF-ORCH0083-LIM3, JRA66IAF-ORCH0083-LIM3 & JRA55ABS-ORCH0083-LIM3 in support of Ocean Modelling paper (Munday et al., 2021). 
Description 1/12o model data archived: CORE2NYF-ORCH0083-LIM3, JRA66IAF-ORCH0083-LIM3 & JRA55ABS-ORCH0083-LIM3 in support of Ocean Modelling paper (Munday et al., 2021). This output is also described in the main award (NE/V103254/1) report, publication ID 622f4841d97530.27119801. 
Type Of Material Data handling & control 
Year Produced 2021 
Provided To Others? No  
Impact 1/12o model data archived: CORE2NYF-ORCH0083-LIM3, JRA66IAF-ORCH0083-LIM3 & JRA55ABS-ORCH0083-LIM3 in support of Ocean Modelling paper (Munday et al., 2021). This output is also described in the main award (NE/V103254/1) report, publication ID 622f4841d97530.27119801. 
 
Description Observing Air-sea Interactions Strategy OASIS 
Organisation University of Exeter
Country United Kingdom 
Sector Academic/University 
PI Contribution Associated project. Liz Kent on a data working group and there has been a lot of interest in the flux software we will be publishing soon. This outcome was also included on the main award (NE/V013254/1) report.
Collaborator Contribution OASIS is a SCOR working group and a program in the UN Decade (see https://airseaobs.org) so there will be an agreement for that.
Impact OBSERVING AIR-SEA INTERACTIONS STRATEGY
Start Year 2021
 
Description SOFLUX 
Organisation University of Tasmania
Country Australia 
Sector Academic/University 
PI Contribution ORCHESTRA is listed as a contributor Southern Ocean Fluxes (SOFLUX) Image Enhancing Air-Sea Flux Observations in the Southern Ocean
Collaborator Contribution ORCHESTRA is listed as a contributor Southern Ocean Fluxes (SOFLUX) Image Enhancing Air-Sea Flux Observations in the Southern Ocean
Impact Achievements during the first project period (2016-2020): When SOFLUX started, one major concern was that air-sea fluxes were not included as EOVs or ECVs. Through engagement from SOFLUX participants (and many others), this issue has been addressed. Concerns about standardized approaches and data management remain, and some are likely to be addressed through the global OASIS effort. SOFLUX has helped to facilitate observing system design studies and has provided a forum for disseminating results through its newsletter and town hall events. Two major SOFLUX studies were published (Wei et al. 2020; Mazloff et al. 2018), as well as an OceanObs19 White Paper on Southern Ocean fluxes (Swart et al. 2019). The working group has worked to share information on in situ flux sensors, flux observing methods, parameterizations, modelling, and assimilation. SOFLUX plays a major role in facilitating an exchange of information between national and European research initiatives, including ORCHESTRA, SOCCOM, SO-CHIC, and ACEAS and providing support for many of these identified priorities. Paper: https://www.frontiersin.org/articles/10.3389/fmars .2019.00421/full
Start Year 2016
 
Title AirSeaFluxCode 
Description AirSeaFluxCode python package for calculation of air-sea fluxes of heat and momentum - will be published with an open-access licence. This output is also listed on the main award (NE/V013254/1) report. Publication ID: 622f457206a028.78459190 
IP Reference  
Protection Trade Mark
Year Protection Granted 2021
Licensed No
Impact AirSeaFluxCode python package for calculation of air-sea fluxes of heat and momentum - will be published with an open-access licence. This output is also listed on the main award (NE/V013254/1) report.
 
Title AABW formation and circulation diagnostics. 
Description George Nurser's AABW formation and circulation diagnostics. This output has also been reported on the main award (NE/V013254/1) report. Publication ID 622f477246c717.03325677 
Type Of Technology Physical Model/Kit 
Year Produced 2021 
Open Source License? Yes  
Impact George Nurser's AABW formation and circulation diagnostics. This output has also been reported on the main award (NE/V013254/1) report. Publication ID 622f477246c717.03325677 
 
Description Scientific Meeting 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This event will take place at the Royal Society 9-10th May 2022. This record for RF is higlighting the preparation that has taken place so far. The event is: Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities: Scientific discussion meeting organised by Dr Andrew Meijers, Professor Corinne Le Quéré CBE FRS, Dr Pedro Monteiro and Dr Jean-Baptiste Sallée. This event is also included in the main award report (NE/V103254/1), publication ID 6230a4276c6302.61372328.
Year(s) Of Engagement Activity 2022
URL https://royalsociety.org/science-events-and-lectures/2022/05/southern-ocean/