Articles | Volume 10, issue 1
https://doi.org/10.5194/os-10-29-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/os-10-29-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
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06 Feb 2014
Research article | Highlight paper |
| 06 Feb 2014
Observed decline of the Atlantic meridional overturning circulation 2004–2012
D. A. Smeed
National Oceanography Centre, European Way, Southampton, SO14 3ZH, UK
G. D. McCarthy
National Oceanography Centre, European Way, Southampton, SO14 3ZH, UK
S. A. Cunningham
Scottish Association for Marine Science, Scottish Marine Institute Oban, Argyll, PA37 1QA, UK
E. Frajka-Williams
National Oceanography Centre, University of Southampton, Waterfront Campus, Southampton SO14 3ZH, UK
D. Rayner
National Oceanography Centre, European Way, Southampton, SO14 3ZH, UK
W. E. Johns
University of Miami, Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL, USA
C. S. Meinen
Atlantic Oceanographic and Meteorological Laboratory, Miami, FL, USA
M. O. Baringer
Atlantic Oceanographic and Meteorological Laboratory, Miami, FL, USA
B. I. Moat
National Oceanography Centre, European Way, Southampton, SO14 3ZH, UK
A. Duchez
National Oceanography Centre, European Way, Southampton, SO14 3ZH, UK
H. L. Bryden
National Oceanography Centre, University of Southampton, Waterfront Campus, Southampton SO14 3ZH, UK
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Alejandra Sanchez-Franks, Eleanor Frajka-Williams, Ben I. Moat, and David A. Smeed
Ocean Sci., 17, 1321–1340, https://doi.org/10.5194/os-17-1321-2021, https://doi.org/10.5194/os-17-1321-2021, 2021
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In the North Atlantic, ocean currents carry warm surface waters northward and return cooler deep waters southward. This type of ocean circulation, known as overturning, is important for the Earth’s climate. This overturning has been measured using a mooring array at 26° N in the North Atlantic since 2004. Here we use these mooring data and global satellite data to produce a new method for monitoring the overturning over longer timescales, which could potentially be applied to different latitudes.
This article is included in the Encyclopedia of Geosciences
Emma L. Worthington, Ben I. Moat, David A. Smeed, Jennifer V. Mecking, Robert Marsh, and Gerard D. McCarthy
Ocean Sci., 17, 285–299, https://doi.org/10.5194/os-17-285-2021, https://doi.org/10.5194/os-17-285-2021, 2021
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The RAPID array has observed the Atlantic meridional overturning circulation (AMOC) since 2004, but the AMOC was directly calculated only five times from 1957–2004. Here we create a statistical regression model from RAPID data, relating AMOC changes to density changes within the different water masses at 26° N, and apply it to historical hydrographic data. The resulting 1981–2016 record shows that the AMOC from 2008–2012 was its weakest since the mid-1980s, but it shows no overall decline.
This article is included in the Encyclopedia of Geosciences
Ben I. Moat, David A. Smeed, Eleanor Frajka-Williams, Damien G. Desbruyères, Claudie Beaulieu, William E. Johns, Darren Rayner, Alejandra Sanchez-Franks, Molly O. Baringer, Denis Volkov, Laura C. Jackson, and Harry L. Bryden
Ocean Sci., 16, 863–874, https://doi.org/10.5194/os-16-863-2020, https://doi.org/10.5194/os-16-863-2020, 2020
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The RAPID 26° N array has been measuring the Atlantic meridional overturning circulation (AMOC) since 2004. Since 2009 the AMOC has, compared with previous years, been in a low state. In 2013–2015, in the northern North Atlantic, strong cooling was observed in the ocean and anticipated to intensify the strength of the AMOC some years later. Here, we analyse the latest results from 26° N and conclude that while the AMOC has increased since 2009, this increase is not statistically significant.
This article is included in the Encyclopedia of Geosciences
E. Frajka-Williams, C. S. Meinen, W. E. Johns, D. A. Smeed, A. Duchez, A. J. Lawrence, D. A. Cuthbertson, G. D. McCarthy, H. L. Bryden, M. O. Baringer, B. I. Moat, and D. Rayner
Ocean Sci., 12, 481–493, https://doi.org/10.5194/os-12-481-2016, https://doi.org/10.5194/os-12-481-2016, 2016
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The ocean meridional overturning circulation (MOC) is predicted by climate models to slow down in this century, resulting in reduced transport of heat northward to mid-latitudes. At 26° N, the Atlantic MOC has been measured continuously for the past decade (2004–2014). In this paper, we discuss the 10-year record of variability, identify the origins of the continued weakening of the circulation, and discuss high-frequency (subannual) compensation between transport components.
This article is included in the Encyclopedia of Geosciences
Marilena Oltmanns, N. Penny Holliday, James Screen, Ben I. Moat, Simon A. Josey, D. Gwyn Evans, and Sheldon Bacon
Weather Clim. Dynam., 5, 109–132, https://doi.org/10.5194/wcd-5-109-2024, https://doi.org/10.5194/wcd-5-109-2024, 2024
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The melting of land ice and sea ice leads to freshwater input into the ocean. Based on observations, we show that stronger freshwater anomalies in the subpolar North Atlantic in winter are followed by warmer and drier weather over Europe in summer. The identified link indicates an enhanced predictability of European summer weather at least a winter in advance. It further suggests that warmer and drier summers over Europe can become more frequent under increased freshwater fluxes in the future.
This article is included in the Encyclopedia of Geosciences
Alexander T. Archibald, Bablu Sinha, Maria Russo, Emily Matthews, Freya Squires, N. Luke Abraham, Stephane Bauguitte, Thomas Bannan, Thomas Bell, David Berry, Lucy Carpenter, Hugh Coe, Andrew Coward, Peter Edwards, Daniel Feltham, Dwayne Heard, Jim Hopkins, James Keeble, Elizabeth C. Kent, Brian King, Isobel R. Lawrence, James Lee, Claire R. Macintosh, Alex Megann, Ben I. Moat, Katie Read, Chris Reed, Malcolm Roberts, Reinhard Schiemann, David Schroeder, Tim Smyth, Loren Temple, Navaneeth Thamban, Lisa Whalley, Simon Williams, Huihui Wu, and Ming-Xi Yang
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2023-405, https://doi.org/10.5194/essd-2023-405, 2024
Preprint under review for ESSD
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Here we present an overview of the data generated as part of the North Atlantic Climate System Integrated Studies (ACSIS) programme which are available through dedicated repositories at the Centre for Environmental Data Analysis (CEDA, www.ceda.ac.uk) and the British Oceanographic Data Centre (BODC, bodc.ac.uk). ACSIS data cover the full North Atlantic System comprising: the North Atlantic Ocean, the atmosphere above it including its composition, Arctic Sea Ice and the Greenland Ice Sheet.
This article is included in the Encyclopedia of Geosciences
Sam C. Jones, Neil J. Fraser, Stuart A. Cunningham, Alan D. Fox, and Mark E. Inall
Ocean Sci., 19, 169–192, https://doi.org/10.5194/os-19-169-2023, https://doi.org/10.5194/os-19-169-2023, 2023
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Warm water is transported from the tropical Atlantic towards western Europe and the Arctic. It loses heat to the atmosphere on the way, which strongly influences the climate. We construct a dataset encircling the North Atlantic basin north of 47° N. We calculate how and where heat enters and leaves the basin and how much cooling must happen in the interior. We find that cooling in the north-eastern Atlantic is a crucial step in controlling the conversion of water to higher densities.
This article is included in the Encyclopedia of Geosciences
Alan D. Fox, Patricia Handmann, Christina Schmidt, Neil Fraser, Siren Rühs, Alejandra Sanchez-Franks, Torge Martin, Marilena Oltmanns, Clare Johnson, Willi Rath, N. Penny Holliday, Arne Biastoch, Stuart A. Cunningham, and Igor Yashayaev
Ocean Sci., 18, 1507–1533, https://doi.org/10.5194/os-18-1507-2022, https://doi.org/10.5194/os-18-1507-2022, 2022
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Observations of the eastern subpolar North Atlantic in the 2010s show exceptional freshening and cooling of the upper ocean, peaking in 2016 with the lowest salinities recorded for 120 years. Using results from a high-resolution ocean model, supported by observations, we propose that the leading cause is reduced surface cooling over the preceding decade in the Labrador Sea, leading to increased outflow of less dense water and so to freshening and cooling of the eastern subpolar North Atlantic.
This article is included in the Encyclopedia of Geosciences
Marilena Oltmanns, N. Penny Holliday, James Screen, D. Gwyn Evans, Simon A. Josey, Sheldon Bacon, and Ben I. Moat
Weather Clim. Dynam. Discuss., https://doi.org/10.5194/wcd-2021-79, https://doi.org/10.5194/wcd-2021-79, 2021
Revised manuscript not accepted
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The Arctic is currently warming twice as fast as the global average. This results in enhanced melting and thus freshwater releases into the North Atlantic. Using a combination of observations and models, we show that atmosphere-ocean feedbacks initiated by freshwater releases into the North Atlantic lead to warmer and drier weather over Europe in subsequent summers. The existence of this dynamical link suggests that European summer weather can potentially be predicted months to years in advance.
This article is included in the Encyclopedia of Geosciences
Tillys Petit, M. Susan Lozier, Simon A. Josey, and Stuart A. Cunningham
Ocean Sci., 17, 1353–1365, https://doi.org/10.5194/os-17-1353-2021, https://doi.org/10.5194/os-17-1353-2021, 2021
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Recent work has highlighted the dominant role of the Irminger and Iceland basins in the production of North Atlantic Deep Water. From our analysis, we find that air–sea fluxes and the ocean surface density field are both key determinants of the buoyancy-driven transformation in the Iceland Basin. However, the spatial distribution of the subpolar mode water (SPMW) transformation is most sensitive to surface density changes as opposed to the direct influence of the air–sea fluxes.
This article is included in the Encyclopedia of Geosciences
Alejandra Sanchez-Franks, Eleanor Frajka-Williams, Ben I. Moat, and David A. Smeed
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In the North Atlantic, ocean currents carry warm surface waters northward and return cooler deep waters southward. This type of ocean circulation, known as overturning, is important for the Earth’s climate. This overturning has been measured using a mooring array at 26° N in the North Atlantic since 2004. Here we use these mooring data and global satellite data to produce a new method for monitoring the overturning over longer timescales, which could potentially be applied to different latitudes.
This article is included in the Encyclopedia of Geosciences
Emma L. Worthington, Ben I. Moat, David A. Smeed, Jennifer V. Mecking, Robert Marsh, and Gerard D. McCarthy
Ocean Sci., 17, 285–299, https://doi.org/10.5194/os-17-285-2021, https://doi.org/10.5194/os-17-285-2021, 2021
Short summary
Short summary
The RAPID array has observed the Atlantic meridional overturning circulation (AMOC) since 2004, but the AMOC was directly calculated only five times from 1957–2004. Here we create a statistical regression model from RAPID data, relating AMOC changes to density changes within the different water masses at 26° N, and apply it to historical hydrographic data. The resulting 1981–2016 record shows that the AMOC from 2008–2012 was its weakest since the mid-1980s, but it shows no overall decline.
This article is included in the Encyclopedia of Geosciences
Ben I. Moat, David A. Smeed, Eleanor Frajka-Williams, Damien G. Desbruyères, Claudie Beaulieu, William E. Johns, Darren Rayner, Alejandra Sanchez-Franks, Molly O. Baringer, Denis Volkov, Laura C. Jackson, and Harry L. Bryden
Ocean Sci., 16, 863–874, https://doi.org/10.5194/os-16-863-2020, https://doi.org/10.5194/os-16-863-2020, 2020
Short summary
Short summary
The RAPID 26° N array has been measuring the Atlantic meridional overturning circulation (AMOC) since 2004. Since 2009 the AMOC has, compared with previous years, been in a low state. In 2013–2015, in the northern North Atlantic, strong cooling was observed in the ocean and anticipated to intensify the strength of the AMOC some years later. Here, we analyse the latest results from 26° N and conclude that while the AMOC has increased since 2009, this increase is not statistically significant.
This article is included in the Encyclopedia of Geosciences
Yang Liu, Jisk Attema, Ben Moat, and Wilco Hazeleger
Earth Syst. Dynam., 11, 77–96, https://doi.org/10.5194/esd-11-77-2020, https://doi.org/10.5194/esd-11-77-2020, 2020
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Poleward meridional energy transport (MET) has significant impact on the climate in the Arctic. In this study, we quantify and intercompare MET at subpolar latitudes from six reanalysis data sets. The results indicate that the spatial distribution and temporal variations of MET differ substantially among the reanalysis data sets. Our study suggests that the MET estimated from reanalyses is useful for the evaluation of energy transports but should be used with great care.
This article is included in the Encyclopedia of Geosciences
Svein Østerhus, Rebecca Woodgate, Héðinn Valdimarsson, Bill Turrell, Laura de Steur, Detlef Quadfasel, Steffen M. Olsen, Martin Moritz, Craig M. Lee, Karin Margretha H. Larsen, Steingrímur Jónsson, Clare Johnson, Kerstin Jochumsen, Bogi Hansen, Beth Curry, Stuart Cunningham, and Barbara Berx
Ocean Sci., 15, 379–399, https://doi.org/10.5194/os-15-379-2019, https://doi.org/10.5194/os-15-379-2019, 2019
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Two decades of observations of the Arctic Mediterranean (AM) exchanges show that the exchanges have been stable in terms of volume transport during a period when many other components of the global climate system have changed. The total AM import is found to be 9.1 Sv and has a seasonal variation in amplitude close to 1 Sv, and maximum import in October. Roughly one-third of the imported water leaves the AM as surface outflow.
This article is included in the Encyclopedia of Geosciences
Conor Murphy, Ciaran Broderick, Timothy P. Burt, Mary Curley, Catriona Duffy, Julia Hall, Shaun Harrigan, Tom K. R. Matthews, Neil Macdonald, Gerard McCarthy, Mark P. McCarthy, Donal Mullan, Simon Noone, Timothy J. Osborn, Ciara Ryan, John Sweeney, Peter W. Thorne, Seamus Walsh, and Robert L. Wilby
Clim. Past, 14, 413–440, https://doi.org/10.5194/cp-14-413-2018, https://doi.org/10.5194/cp-14-413-2018, 2018
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This work reconstructs a continuous 305-year rainfall record for Ireland. The series reveals remarkable variability in decadal rainfall – far in excess of the typical period of digitised data. Notably, the series sheds light on exceptionally wet winters in the 1730s and wet summers in the 1750s. The derived record, one of the longest continuous series in Europe, offers a firm basis for benchmarking other long-term records and reconstructions of past climate both locally and across Europe.
This article is included in the Encyclopedia of Geosciences
Robert Marsh, Ivan D. Haigh, Stuart A. Cunningham, Mark E. Inall, Marie Porter, and Ben I. Moat
Ocean Sci., 13, 315–335, https://doi.org/10.5194/os-13-315-2017, https://doi.org/10.5194/os-13-315-2017, 2017
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To the west of Britain and Ireland, a strong ocean current follows the steep slope that separates the deep Atlantic and the continental shelf. This “Slope Current” exerts an Atlantic influence on the North Sea and its ecosystems. Using a combination of computer modelling and archived data, we find that the Slope Current weakened over 1988–2007, reducing Atlantic influence on the North Sea, due to a combination of warming of the subpolar North Atlantic and weakening winds to the west of Scotland.
This article is included in the Encyclopedia of Geosciences
Christopher S. Meinen, Silvia L. Garzoli, Renellys C. Perez, Edmo Campos, Alberto R. Piola, Maria Paz Chidichimo, Shenfu Dong, and Olga T. Sato
Ocean Sci., 13, 175–194, https://doi.org/10.5194/os-13-175-2017, https://doi.org/10.5194/os-13-175-2017, 2017
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This article is included in the Encyclopedia of Geosciences
E. Frajka-Williams, C. S. Meinen, W. E. Johns, D. A. Smeed, A. Duchez, A. J. Lawrence, D. A. Cuthbertson, G. D. McCarthy, H. L. Bryden, M. O. Baringer, B. I. Moat, and D. Rayner
Ocean Sci., 12, 481–493, https://doi.org/10.5194/os-12-481-2016, https://doi.org/10.5194/os-12-481-2016, 2016
Short summary
Short summary
The ocean meridional overturning circulation (MOC) is predicted by climate models to slow down in this century, resulting in reduced transport of heat northward to mid-latitudes. At 26° N, the Atlantic MOC has been measured continuously for the past decade (2004–2014). In this paper, we discuss the 10-year record of variability, identify the origins of the continued weakening of the circulation, and discuss high-frequency (subannual) compensation between transport components.
This article is included in the Encyclopedia of Geosciences
P. Achtert, I. M. Brooks, B. J. Brooks, B. I. Moat, J. Prytherch, P. O. G. Persson, and M. Tjernström
Atmos. Meas. Tech., 8, 4993–5007, https://doi.org/10.5194/amt-8-4993-2015, https://doi.org/10.5194/amt-8-4993-2015, 2015
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Doppler lidar wind measurements were obtained during a 3-month Arctic cruise in summer 2014. Ship-motion effects were compensated by combining a commercial Doppler lidar with a custom-made motion-stabilisation platform. This enables the retrieval of wind profiles in the Arctic boundary layer with uncertainties comparable to land-based lidar measurements and standard radiosondes. The presented set-up has the potential to facilitate continuous ship-based wind profile measurements over the oceans.
This article is included in the Encyclopedia of Geosciences
J. Prytherch, M. J. Yelland, I. M. Brooks, D. J. Tupman, R. W. Pascal, B. I. Moat, and S. J. Norris
Atmos. Chem. Phys., 15, 10619–10629, https://doi.org/10.5194/acp-15-10619-2015, https://doi.org/10.5194/acp-15-10619-2015, 2015
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Signals at scales associated with wave and platform motion are often apparent in ship-based turbulent flux measurements, but it has been uncertain whether this is due to measurement error or to wind-wave interactions. We show that the signal has a dependence on horizontal ship velocity and that removing the signal reduces the dependence of the momentum flux on the orientation of the ship to the wind. We conclude that the signal is a bias due to time-varying motion-dependent flow distortion.
This article is included in the Encyclopedia of Geosciences
M. Borghini, H. Bryden, K. Schroeder, S. Sparnocchia, and A. Vetrano
Ocean Sci., 10, 693–700, https://doi.org/10.5194/os-10-693-2014, https://doi.org/10.5194/os-10-693-2014, 2014
H. L. Bryden, B. A. King, G. D. McCarthy, and E. L. McDonagh
Ocean Sci., 10, 683–691, https://doi.org/10.5194/os-10-683-2014, https://doi.org/10.5194/os-10-683-2014, 2014
S. J. Norris, I. M. Brooks, B. I. Moat, M. J. Yelland, G. de Leeuw, R. W. Pascal, and B. Brooks
Ocean Sci., 9, 133–145, https://doi.org/10.5194/os-9-133-2013, https://doi.org/10.5194/os-9-133-2013, 2013
Related subject area
Approach: In situ Observations | Depth range: Deep Ocean | Geographical range: Deep Seas: North Atlantic | Phenomena: Temperature, Salinity and Density Fields
Pending recovery in the strength of the meridional overturning circulation at 26° N
Ben I. Moat, David A. Smeed, Eleanor Frajka-Williams, Damien G. Desbruyères, Claudie Beaulieu, William E. Johns, Darren Rayner, Alejandra Sanchez-Franks, Molly O. Baringer, Denis Volkov, Laura C. Jackson, and Harry L. Bryden
Ocean Sci., 16, 863–874, https://doi.org/10.5194/os-16-863-2020, https://doi.org/10.5194/os-16-863-2020, 2020
Short summary
Short summary
The RAPID 26° N array has been measuring the Atlantic meridional overturning circulation (AMOC) since 2004. Since 2009 the AMOC has, compared with previous years, been in a low state. In 2013–2015, in the northern North Atlantic, strong cooling was observed in the ocean and anticipated to intensify the strength of the AMOC some years later. Here, we analyse the latest results from 26° N and conclude that while the AMOC has increased since 2009, this increase is not statistically significant.
This article is included in the Encyclopedia of Geosciences
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