The North Atlantic Climate System Integrated Study (ACSIS) - 1 year extension

Lead Research Organisation: National Oceanography Centre (WEF011019)
Department Name: Science and Technology

Abstract

Major changes are occurring across the North Atlantic climate system: in oceanic and atmospheric temperatures and circulation, in sea ice thickness and extent, and in key atmospheric constituents such as ozone, methane and particles known as aerosols. Many observed changes are unprecedented in instrumental records. Changes in the North Atlantic directly affect the UK's climate, weather and air quality, with major economic impacts on agriculture, fisheries, water, energy, transport and health. The North Atlantic also has global importance, since changes here drive changes in climate, hazardous weather and air quality further afield, such as in North America, Africa, and Asia. The ACSIS extension is a 1 year continuation of an ongoing 5-year strategic research programme called ACSIS: the North Atlantic Climate System Integrated Study. ACSIS brings together and exploits a wide range of capabilities and expertise in the UK environmental science community. Its goal is to enhance the UK's capability to detect, attribute (i.e. explain the causes of) and predict changes in the North Atlantic Climate System. ACSIS is delivering new understanding of the North Atlantic climate system by integrating new and old observations of atmospheric physics and chemistry, of the ocean state and of Arctic ice, complemented by detailed data analysis and state-of-the-art computer simulations. Observations are obtained from diverse sources including NERC's observational sites in the North Atlantic, satellite remote sensing and the NCAS FAAM aeroplane. The computer modelling component is providing simulations of the atmosphere, ocean, and sea ice with unprecedented spatial detail. The ACSIS extension will exploit advances made during the past 5 years to address specific new research questions which have arisen recently. It will investigate exciting evidence that changes in the climate of the North Atlantic/European region are much more predictable than was previously thought and will start to assess the impact of North Atlantic changes on the UK environment.
 
Description As a result of the work funded through ACSIS there have been significant steps forward in our understanding of the Atlantic Meridional Overturning Circulation (AMOC), a major Atlantic Ocean circulation phenomenon which brings heat and salt from the subtropics to the Northern North Atlantic, helping to maintain a relatively mild north western European climate relative to regions at the same latitude elsewhere on the globe. We have learned from model simulations that changes to surface cooling in the Irminger Sea between Greenland and Iceland were responsible for the downturn in the AMOC that occurred between the 1980s and the 2000s. Previously the focus was on deep convection in the Labrador Sea. Our work has helped to shift the paradigm away from deep ocean convection and towards gradual transformation of watermasses as they circulate around and are exported southwards from the Subpolar North Atlantic (which spans the ocean region from about 45N to about 65N). We have also documented the subsequent very gradual increase of the AMOC from 2010 onwards and are investigating how the changing AMOC impacts the surface temperatures in the subpolar North Atlantic. Finally we have found from climate model projections that sea level around the UK is likely to increase by a few 10s of cm over and above the latest IPCC projections due to changes in ocean circulation caused by global warming.
Exploitation Route The outcomes will inform the next round of NERC LTS-M national capability programmes such as CANARI. However they will also be highly influential in the international development of Atlantic climate science in the next 5-10 years (via our legacy scientific papers and datasets and especially a substantial number of synthesis papers). Beyond the research community our results are likely to have an impact on adaptation and mitigation policy via our work on climate storylines which paint plausible future scenarios based on solid scientific foundations. Our sea level work in particular is likely to have impact in this way.
Sectors Agriculture, Food and Drink,Energy,Environment,Financial Services, and Management Consultancy,Healthcare,Leisure Activities, including Sports, Recreation and Tourism,Transport

 
Title Intermediate resolution climate model FORTE2 
Description This is a significantly updated version of a fast, inexpensive and low resolution coupled climate model developed previously at the National Oceanography Centre and used for idealised climate experiments.The updated version now runs on parallel processors using MPI software, has a more advanced atmospheric component including a resolved stratosphere and can simulate 300+ model years in 1 day of real time. This opens up the possibility of investigating paleaoclimate with a full primitive equation model, as well as studying contemporary climate and performing climate projections at a fraction of the cost of standard CMIP-style climate models. In particular the model is readily configurable, allowing control over land geometry and orography, ocean topography, and geophysical parameters such as rotation rate, solar input, orbital parameters etc. 
Type Of Material Improvements to research infrastructure 
Year Produced 2021 
Provided To Others? Yes  
Impact As it has just been released, impact is restricted to the publication which documents the model performance 
URL https://zenodo.org/record/4108373#.YijBQb3P3rI
 
Title 1/4 degree historical forced ocean simulation 
Description Output from ocean model simulation forced by CORE2 estimates of surface atmospheric conditions. Fields stored are monthly temperature, salinity, ocean currents and other fields for 1958-2007. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
Impact Understanding of the proximate cause of the observed variability (increase up to the mid 1990s, and then an ongoing decrease) of the Atlantic Meridional Overturning Circulation. This has been written up as a journal article: Megann, Alex ; Blaker, Adam ; Josey, Simon ; New, Adrian ; Sinha, Bablu. 2021 Mechanisms for late 20th and early 21st century decadal AMOC variability. Journal of Geophysical Research: Oceans, 126 (12). https://doi.org/10.1029/2021JC017865 
URL https://catalogue.ceda.ac.uk/uuid/119a5d4795c94d2e94f610647640edc0
 
Title Monthly ocean and sea-ice output from 1/4° NEMO GO6 integration forced by CORE2 data 
Description Monthly output from an integration of the GO6 configuration of the NEMO (Nucleus for European Modelling of the Ocean) ocean and sea-ice model, forced by the CORE2 (Coordinated Ocean-ice Reference Experiments version 2.0) corrected inter-annual forcing (CIAF) surface field dataset. UK Global Ocean GO6 consists of version 3.6 of NEMO and version 5.2.1 of the CICE (Community Ice CodE) sea-ice model, and the present simulation is on the global eORCA025 1/4° grid. The ocean is initialised from a climatology based on the EN3 monthly objective analysis (Ingleby and Huddleston, 2007) averaged over years 2004-2008, and is integrated from 1958 to 2007. The model was run on the Archer supercomputing platform through the Rose/Cylc interface on Puma, and the run ID on the Puma system is u-ap795. The integrations were funded by the Natural Environment Research Council (NERC) under the Atlantic Climate System Integrated Study (ACSIS) project (NE/N018044/1). 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
Impact The data were used to write a paper on AMOC variability 1948-2020: 10.5285/119a5d4795c94d2e94f610647640edc0 
URL https://catalogue.ceda.ac.uk/uuid/119a5d4795c94d2e94f610647640edc0
 
Title Monthly ocean and sea-ice output from 1/4° NEMO GO6 integration forced by DFS5.2 data 
Description Monthly output from an integration of the UK Global Ocean, GO6, configuration of the NEMO (Nucleus for European Modelling of the Ocean) ocean and sea-ice model, forced by the DFS5.2 (Drakkar Forcing Set: Dussin et al, 2016) surface field dataset. GO6 consists of version 3.6 of NEMO and version 5.2.1 of the CICE (Community Ice CodE) sea-ice model, and the present simulation is on the global eORCA025 1/4° grid. The ocean is initialised from a climatology based on the EN3 monthly objective analysis (Ingleby and Huddleston, 2007) averaged over years 2004-2008, and is integrated from 1958 to 2015. The sea-ice fields are only available for the period 1958 to 2008. The model was run on the Archer supercomputing platform through the Rose/Cylc interface on Puma, and the run ID on the Puma system is u-ao882. The integrations were funded by the Natural Environment Research Council (NERC) under the Atlantic Climate System Integrated Study (ACSIS) project (NE/N018044/1). 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
Impact The data has been used to write a paper on historical AMOC variability 1948-2020: Megann, Alex ; Blaker, Adam ; Josey, Simon ; New, Adrian ; Sinha, Bablu. 2021 Mechanisms for late 20th and early 21st century decadal AMOC variability. Journal of Geophysical Research: Oceans, 126 (12). https://doi.org/10.1029/2021JC017865 
URL https://catalogue.ceda.ac.uk/uuid/a0708d25b4fc44c5ab1b06e12fef2f2e
 
Title Monthly ocean and sea-ice output from 1/4° NEMO GO6 integration forced by JRA55 data 
Description Monthly output from an integration of the UK Global Ocean, GO6, configuration of the NEMO (Nucleus for European Modelling of the Ocean) ocean and sea-ice model, forced by the JRA-55 (Japanese 55-year atmospheric reanalysis: Tsujino, 2018) surface field dataset. GO6 consists of version 3.6 of NEMO and version 5.2.1 of the CICE (Community Ice CodE) sea-ice model, and the present simulation is on the global eORCA025 1/4° grid. The ocean is initialised from a climatology based on the EN3 monthly objective analysis (Ingleby and Huddleston, 2007) averaged over years 2004-2008, and is integrated from 1958 to 2020. The sea-ice fields are only available for the period 1989 to 2001. The model was run on the Archer supercomputing platform through the Rose/Cylc interface on Puma, and the run ID on the Puma system is u-ba494. The integrations were funded by the Natural Environment Research Council (NERC) under the Atlantic Climate System Integrated Study (ACSIS) project (NE/N018044/1). 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
Impact The data has been used to write a paper on AMOC variability 1948-2020: Megann, Alex ; Blaker, Adam ; Josey, Simon ; New, Adrian ; Sinha, Bablu. 2021 Mechanisms for late 20th and early 21st century decadal AMOC variability. Journal of Geophysical Research: Oceans, 126 (12). https://doi.org/10.1029/2021JC017865 
URL https://catalogue.ceda.ac.uk/uuid/4c545155dfd145a1b02a5d0e577ae37d
 
Title Subpolar North Atlantic ocean heat content (surface to 1000m) using objectively mapped Argo profiling float data. 
Description Monthly ocean heat content (surface to 1000m) in the North Atlantic Subpolar region calculated using objectively mapped Argo profiling float data. This calculation of ocean heat content used potential enthalpy (from TEOS10) instead of potential temperature, which removes the need for a fixed specific heat capacity. Density was from in situ density rather than a fixed value. This was funded by the Natural Environment Research Council (NERC) under the Atlantic Climate System Integrated Study (ACSIS) project (NE/N018044/1). 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
Impact used as an Atlantic Climate Indicator by the NERC ACSIS Programme 
URL https://www.bodc.ac.uk/data/published_data_library/catalogue/10.5285/d23c26bc-6e6c-5bbf-e053-6c86abc...
 
Title Subpolar North Atlantic ocean heat content (surface to 1000m) using the EN4.2.2 temperature data set. 
Description Monthly ocean heat content (surface to 1000m) in the North Atlantic Subpolar region, from 1950 to 2020, calculated using the EN4.2.2 temperature data set. This calculation of ocean heat content used potential enthalpy (from TEOS10) instead of potential temperature, which removes the need for a fixed specific heat capacity. Density was from insitu density rather than a fixed value. This was funded by the Natural Environment Research Council (NERC) under the Atlantic Climate System Integrated Study (ACSIS) project (NE/N018044/1). 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
Impact used as an Atlantic Climate Indicator by the ACSIS programme 
URL https://www.bodc.ac.uk/data/published_data_library/catalogue/10.5285/d09552c1-5e31-55e1-e053-6c86abc...
 
Description GreenBlock 
Organisation University of Lincoln
Department School of Geography
Country United Kingdom 
Sector Academic/University 
PI Contribution providing high resolution coupled model output and advice on how to use it
Collaborator Contribution expertise in atmospheric processes related to Greenland Blocking and implications for regional weather and climate
Impact The collaboration has only just started so output and outcomes will occur int he next 2-3 years. The collaboration involves two disciplines: oceanography and meteorology
Start Year 2022
 
Title Fast, Parallel intermediate complexity climate model (FORTE 2.0) 
Description This is a climate model with relatively low resolution (2.8 degrees in the atmosphere and 2 degrees in the ocean), but optimised for MP and open MP parallel processing so that it is fast enough to multicentennial and millennial climate simulations. It is easily configurable so that different continental and orographic/ocean bathymetry configurations can be explored. The model can be run with our without a stratosphere. There are basic thermodynamic sea ice and land soi/vegetation models 
Type Of Technology Software 
Year Produced 2021 
Open Source License? Yes  
Impact As this has only just been released, we are expecting impacts to build up over time. A paper has been published describing the model: FORTE 2.0: a fast, parallel and flexible coupled climate model. Blaker, A., Joshi, M., Sinha, B., Stevens, D., Smith, R. & Hirschi, J., 19 Jan 2021, In : Geoscientific Model Development. 14, 1, p. 275-293 19 p. 
URL http://doi.org/10.5281/zenodo.3632569