Articles | Volume 12, issue 2
https://doi.org/10.5194/os-12-481-2016
© Author(s) 2016. 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-12-481-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Compensation between meridional flow components of the Atlantic MOC at 26° N
E. Frajka-Williams
CORRESPONDING AUTHOR
Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton, SO14 3ZH, UK
C. S. Meinen
Atlantic Oceanographic and Meteorological Laboratory, Physical Oceanography Division, 4301 Rickenbacker Causeway, Miami, FL 33149, USA
W. E. Johns
University of Miami, Rosentiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL, USA
D. A. Smeed
National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK
A. Duchez
National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK
A. J. Lawrence
Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton, SO14 3ZH, UK
D. A. Cuthbertson
Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton, SO14 3ZH, UK
G. D. McCarthy
National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK
H. L. Bryden
Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton, SO14 3ZH, UK
M. O. Baringer
Atlantic Oceanographic and Meteorological Laboratory, Physical Oceanography Division, 4301 Rickenbacker Causeway, Miami, FL 33149, USA
B. I. Moat
National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK
D. Rayner
National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK
Related authors
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
Short summary
Short summary
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.
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.
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
Short summary
Short summary
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.
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
Revised manuscript accepted for ESSD
Short summary
Short summary
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.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
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.
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.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
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
Short summary
Short summary
This study investigates the variability of the Deep Western Boundary Current at 34.5° S. This current carries a large part of the cold deep limb of the Meridional Overturning Circulation, which is a crucial part of the ocean system and has impacts on global weather patterns. Study of this current in the South Atlantic has been limited in the past, and this new study provides insights into the strength and variability of the current as well as the causes for the observed changes.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
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
D. A. Smeed, G. D. McCarthy, S. A. Cunningham, E. Frajka-Williams, D. Rayner, W. E. Johns, C. S. Meinen, M. O. Baringer, B. I. Moat, A. Duchez, and H. L. Bryden
Ocean Sci., 10, 29–38, https://doi.org/10.5194/os-10-29-2014, https://doi.org/10.5194/os-10-29-2014, 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: All Depths | Geographical range: Deep Seas: North Atlantic | Phenomena: Current Field
3D reconstruction of ocean velocity from high-frequency radar and acoustic Doppler current profiler: a model-based assessment study
Mass, nutrients and dissolved organic carbon (DOC) lateral transports off northwest Africa during fall 2002 and spring 2003
Surface predictor of overturning circulation and heat content change in the subpolar North Atlantic
Arctic Mediterranean exchanges: a consistent volume budget and trends in transports from two decades of observations
Atlantic Meridional Overturning Circulation at 14.5° N in 1989 and 2013 and 24.5° N in 1992 and 2015: volume, heat, and freshwater transports
Atlantic water flow through the Faroese Channels
A stable Faroe Bank Channel overflow 1995–2015
Deep drivers of mesoscale circulation in the central Rockall Trough
Impact of a 30% reduction in Atlantic meridional overturning during 2009–2010
Atlantic transport variability at 25° N in six hydrographic sections
On the seasonal cycles and variability of Florida Straits, Ekman and Sverdrup transports at 26° N in the Atlantic Ocean
The contribution of eastern-boundary density variations to the Atlantic meridional overturning circulation at 26.5° N
Ivan Manso-Narvarte, Erick Fredj, Gabriel Jordà, Maristella Berta, Annalisa Griffa, Ainhoa Caballero, and Anna Rubio
Ocean Sci., 16, 575–591, https://doi.org/10.5194/os-16-575-2020, https://doi.org/10.5194/os-16-575-2020, 2020
Short summary
Short summary
Our main aim is to study the feasibility of reconstructing oceanic currents by extending the data obtained from coastal multiplatform observatories to nearby areas in 3D in the SE Bay of Biscay. To that end, two different data-reconstruction methods with different approaches were tested, providing satisfactory results. This work is a first step towards the real applicability of these methods in this study area, and it shows the capabilities of the methods for a wide range of applications.
Nadia Burgoa, Francisco Machín, Ángeles Marrero-Díaz, Ángel Rodríguez-Santana, Antonio Martínez-Marrero, Javier Arístegui, and Carlos Manuel Duarte
Ocean Sci., 16, 483–511, https://doi.org/10.5194/os-16-483-2020, https://doi.org/10.5194/os-16-483-2020, 2020
Short summary
Short summary
The main objective of the study is to analyze the export of carbon to the open ocean from the rich waters of the upwelling system of North Africa. South of the Canary Islands, permanent upwelling interacts with other physical processes impacting the main biogeochemical processes. Taking advantage of data from two cruises combined with the outputs of models, important conclusions from the differences observed between seasons are obtained, largely related to changes in the CVFZ in this area.
Damien G. Desbruyères, Herlé Mercier, Guillaume Maze, and Nathalie Daniault
Ocean Sci., 15, 809–817, https://doi.org/10.5194/os-15-809-2019, https://doi.org/10.5194/os-15-809-2019, 2019
Short summary
Short summary
In the North Atlantic, ocean currents transport warm waters northward in the upper water column, and cold waters southwards at depth. This circulation is here reconstructed from surface data and thermodynamics theory. Its driving role in recent temperature changes (1993–2017) in the North Atlantic is evidenced, and predictions of near-future variability (5 years) are provided and discussed.
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
Short summary
Short summary
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.
Yao Fu, Johannes Karstensen, and Peter Brandt
Ocean Sci., 14, 589–616, https://doi.org/10.5194/os-14-589-2018, https://doi.org/10.5194/os-14-589-2018, 2018
Short summary
Short summary
Hydrographic analysis in the Atlantic along 14.5° N and 24.5° N shows that between the periods of 1989/92 and 2013/15, the Antarctic Intermediate Water became warmer and saltier at 14.5° N, and that the Antarctic Bottom Water became lighter at both latitudes. By applying a box inverse model, the Atlantic Meridional Overturning Circulation (AMOC) was determined. Comparison among the inverse solution, GECCO2, RAPID, and MOVE shows that the AMOC has not significantly changed in the past 20 years.
Bogi Hansen, Turið Poulsen, Karin Margretha Húsgarð Larsen, Hjálmar Hátún, Svein Østerhus, Elin Darelius, Barbara Berx, Detlef Quadfasel, and Kerstin Jochumsen
Ocean Sci., 13, 873–888, https://doi.org/10.5194/os-13-873-2017, https://doi.org/10.5194/os-13-873-2017, 2017
Short summary
Short summary
On its way towards the Arctic, an important branch of warm Atlantic water passes through the Faroese Channels, but, in spite of more than a century of investigations, the detailed flow pattern through this channel system has not been resolved. This has strong implications for estimates of oceanic heat transport towards the Arctic. Here, we combine observations from various sources, which together paint a coherent picture of the Atlantic water flow and heat transport through this channel system.
Bogi Hansen, Karin Margretha Húsgarð Larsen, Hjálmar Hátún, and Svein Østerhus
Ocean Sci., 12, 1205–1220, https://doi.org/10.5194/os-12-1205-2016, https://doi.org/10.5194/os-12-1205-2016, 2016
Short summary
Short summary
The Faroe Bank Channel is one of the main passages for the flow of cold dense water from the Arctic into the depths of the world ocean where it feeds the deep branch of the AMOC. Based on in situ measurements, we show that the volume transport of this flow has been stable from 1995 to 2015. The water has warmed, but salinity increase has maintained its high density. Thus, this branch of the AMOC did not weaken during the last 2 decades, but increased its heat transport into the deep ocean.
T. J. Sherwin, D. Aleynik, E. Dumont, and M. E. Inall
Ocean Sci., 11, 343–359, https://doi.org/10.5194/os-11-343-2015, https://doi.org/10.5194/os-11-343-2015, 2015
Short summary
Short summary
The Rockall Trough feeds warm salty water to Polar regions and the European Shelf. Detailed observations from an underwater glider show that a) the meandering surface current field in the central trough is driven by deep eddies; b) chance circulations deflect the eastern slope current and warm the western side; c) and altimeter observations omit the mean flow in the narrow slope current. There are wider implications for satellite altimeter observations, ocean monitoring and ocean model results.
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
C. P. Atkinson, H. L. Bryden, S. A. Cunningham, and B. A. King
Ocean Sci., 8, 497–523, https://doi.org/10.5194/os-8-497-2012, https://doi.org/10.5194/os-8-497-2012, 2012
C. P. Atkinson, H. L. Bryden, J. J-M. Hirschi, and T. Kanzow
Ocean Sci., 6, 837–859, https://doi.org/10.5194/os-6-837-2010, https://doi.org/10.5194/os-6-837-2010, 2010
M. P. Chidichimo, T. Kanzow, S. A. Cunningham, W. E. Johns, and J. Marotzke
Ocean Sci., 6, 475–490, https://doi.org/10.5194/os-6-475-2010, https://doi.org/10.5194/os-6-475-2010, 2010
Cited articles
Atkinson, C. P., Bryden, H. L., Cunningham, S. A., and King, B. A.: Atlantic transport variability at 25° N in six hydrographic sections, Ocean Sci., 8, 497–523, https://doi.org/10.5194/os-8-497-2012, 2012.
Bryden, H. L., Longworth, H. R., and Cunningham, S. A.: Slowing of the Atlantic meridional overturning circulation at 25° N, Nature, 438, 655–657, 2005.
Bryden, H. L., Mujahid, A., Cunningham, S. A., and Kanzow, T.: Adjustment of the basin-scale circulation at 26° N to variations in Gulf Stream, deep western boundary current and Ekman transports as observed by the Rapid array, Ocean Sci., 5, 421–433, https://doi.org/10.5194/os-5-421-2009, 2009.
Bryden, H. L., King, B. A., McCarthy, G. D., and McDonagh, E. L.: Impact of a 30 % reduction in Atlantic meridional overturning during 2009–2010, Ocean Sci., 10, 683–691, https://doi.org/10.5194/os-10-683-2014, 2014.
Cabanes, C., Lee, T., and Fu, L.-L.: Mechanisms of interannual variations of the Meridional Overturning Circulation of the North Atlantic, J. Phys. Ocean., 38, 467–480, https://doi.org/10.1175/2007JPO3726.1, 2008.
Chidichimo, M. P., Kanzow, T., Cunningham, S. A., Johns, W. E., and Marotzke, J.: The contribution of eastern-boundary density variations to the Atlantic meridional overturning circulation at 26.5° N, Ocean Sci., 6, 475–490, https://doi.org/10.5194/os-6-475-2010, 2010.
Clément, L., Frajka-Williams, E., Szuts, Z. B., and Cunningham, S. A.: The vertical structure of eddies and Rossby waves and their effect on the Atlantic MOC at 26° N, J. Geophys. Res., 119, 6479–6498, https://doi.org/10.1002/2014JC010146, 2014.
Cunningham, S. A., Kanzow, T., Rayner, D., Baringer, M. O., Johns, W. E., Marotzke, J., Longworth, H. R., Grant, E. M., Hirschi, J. J.-M., Beal, L. M., Meinen, C. S., and Bryden, H. L.: Temporal variability of the Atlantic meridional overturning circulation at 26.5° N, Science, 317, 935–938, 2007.
Cunningham, S. A., Roberts, C., Frajka-Williams, E., Johns, W. E., Hobbs, W., Palmer, M. D., Rayner, D., Smeed, D. A., and McCarthy, G. D.: Atlantic MOC slowdown cooled the subtropical ocean, Geophys. Res. Lett., 40, 6202–6207, https://doi.org/10.1002/2013GL058464, 2014.
Desaubies, Y. and Gregg, M. C.: Reversible and irreversible finestructure, J. Phys. Ocean., 11, 541–556, 1981.
DiNezio, P. N., Gramer, L. J., Johns, W. E., Meinen, C. S., and Baringer, M. O.: Observed interannual variability of the Florida Current: Wind forcing and the North Atlantic Oscillation, J. Phys. Oceanogr., 39, 721–736, 2009.
Duchez, A., Frajka-Williams, E., Castro, N., Hirschi, J. J.-M., and Coward, A.: Seasonal to interannual variability in density around the Canary Islands and their influence on the AMOC at 26.5° N, J. Geophys. Res., 119, 1843–1860, https://doi.org/10.1002/2013JC009416, 2014.
Elipot, S., Hughes, C., Olhede, S., and Toole, J.: Coherence of western boundary pressure at the RAPID WAVE array: Boundary wave adjustments or deep western boundary current advection?, J. Phys. Oceanogr., 43, 744–765, 2013.
Elipot, S., Frajka-Williams, E., Hughes, C., and Willis, J.: The observed North Atlantic MOC, its meridional coherence and ocean bottom pressure, J. Phys. Oceanogr., 44, 517–537, https://doi.org/10.1175/JPO-D-13-026.1, 2014.
Emery, W. J. and Thomson, R. E.: Data Analysis Methods in Physical Oceanography, Elsevier, Amsterdam, the Netherlands, 2nd edn., 2004.
Frajka-Williams, E.: Estimating the Atlantic MOC at 26° N using satellite altimetry and cable measurements, Geophys. Res. Lett., 42, 3458–3464, https://doi.org/10.1002/2015GL063220, 2015.
Frajka-Williams, E., Johns, W. E., Meinen, C. S., Beal, L. M., and Cunningham, S. A.: Eddy impacts on the Florida Current, Geophys. Res. Lett., 40, 349–353, https://doi.org/10.1002/grl.50115, 2013.
Grinsted, A., Moore, J. C., and Jevrejeva, S.: Application of the cross wavelet transform and wavelet coherence to geophysical time series, Nonlin. Processes Geophys., 11, 561–566, https://doi.org/10.5194/npg-11-561-2004, 2004.
Jayne, S. R. and Marotzke, J.: The dynamics of ocean heat transport variability, Rev. Geophys., 39, 385–411, 2001.
Johns, W. E., Baringer, M. O., Beal, L. M., Cunningham, S. A., Kanzow, T., Bryden, H. L., Hirschi, J. J.-M., Marotzke, J., Meinen, C. S., Shaw, B., and Curry, R.: Continuous, array-based estimates of Atlantic Ocean heat transport at 26.5° N, J. Climate, 24, 2429–2449, 2011.
Kanzow, T., Cunningham, S. A., Rayner, D., Hirschi, J. J.-M., Johns, W. E., Baringer, M. O., Bryden, H. L., Beal, L. M., Meinen, C. S., and Marotzke, J.: Observed flow compensation associated with the MOC at 26.5° N in the Atlantic, Science, 317, 938–941, 2007.
Kanzow, T., Johnson, H. L., Marshall, D. P., Cunningham, S. A., Hirschi, J. J.-M., Mujahid, A., Bryden, H. L., and Johns, W. E.: Basinwide Integrated Volume Transports in an Eddy-Filled Ocean, J. Phys. Oceanogr., 39, 3091–3110, 2009.
Kanzow, T., Cunningham, S. A., Johns, W. E., Hirschi, J. J.-M., Marotzke, J., Baringer, M. O., Meinen, C. S., Chidichimo, M. P., Atkinson, C., Beal, L. M., Bryden, H. L., and Collins, J.: Seasonal variability of the Atlantic meridional overturning circulation at 26.5° N, J. Climate, 23, 5678–5698, https://doi.org/10.1175/2010JCLI3389.1, 2010.
Killworth, P. D.: A simple linear model of the depth dependence of the wind-driven variability of the Meridional Overturning Circulation, J. Phys. Oceanogr., 38, 492–502, 2008.
Landerer, F. W., Wiese, D. N., Bentel, K., Boening, C., and Watkins, M. M.: North Atlantic meridional overturning circulation variations from GRACE ocean bottom pressure anomalies, Geophys. Res. Lett.,42, 8114–8121, https://doi.org/10.1002/2015GL065730, 2015.
Lin, Y., Greatbatch, R. J., and Sheng, J.: A model study of the vertically integrated transport variability through the Yucatan Channel: Role of Loop Current evolution and flow compensation around Cuba, J. Geophys. Res., 114, C08003, https://doi.org/10.1029/2008JC005199, 2009.
Longworth, H. R., Bryden, H. L., and Baringer, M. O.: Historical variability in Atlantic meridional baroclinic transport at 26.5° N from boundary dynamic height observations, Deep-Sea Res. Pt. II, 58, 1754–1767, 2011.
McCarthy, G., Frajka-Williams, E., Johns, W. E., Baringer, M. O., Meinen, C. S., Bryden, H. L., Rayner, D., Duchez, A., Roberts, C. D., and Cunningham, S. A.: Observed interannual variability of the Atlantic MOC at 26.5° N, Geophys. Res. Lett., 39, L19609, https://doi.org/10.1029/2012GL052933, 2012.
McCarthy, G. D., Smeed, D. A., Johns, W. E., Frajka-Williams, E., Moat, B. I., Rayner, D., Baringer, M. O., Meinen, C. S., and Bryden, H. L.: Measuring the Atlantic meridional overturning circulation at 26° N, Prog. Oceanogr., 130, 91–111, https://doi.org/10.1016/j.pocean.2014.10.006, 2015.
Meinen, C. S., Baringer, M. O., and Garcia, R. F.: Florida Current transport variability: An analysis of annual and longer-period signals, Deep-Sea Res. Pt. I, 57, 835–846, 2010.
Mielke, C., Frajka-Williams, E., and Baehr, J.: Observed and simulated variability of the AMOC at 26° N and 41° N, Geophys. Res. Lett., 40, 1159–1164, https://doi.org/10.1002/grl.50233, 2013.
Percival, D. B. and Walden, A. T.: Spectral Analysis for Physical Applications, Cambridge University Press, Cambridge, UK, 1998.
Pillar, H., Heimbach, P., Johnson, H., and Marshall, D.: Dynamical attribution of recent variability in Atlantic overturning, J. Climate, https://doi.org/10.1175/JCLI-D-15-0727.1, 2016.
Polo, I., Robson, J., Sutton, R., and Bamaseda, M.: The importance of wind and buoyancy forcing of the boundary density variations and the geostrophic component of the AMOC at 26° N, J. Phys. Oceanogr., 44, 2387–2408, 2014.
Rayner, D., Hirschi, J. J.-M., Kanzow, T., Johns, W. E., Wright, P. G., Frajka-Williams, E., Bryden, H. L., Meinen, C. S., Baringer, M. O., Marotzke, J., Beal, L. M., and Cunningham, S. A.: Monitoring the Atlantic meridional overturning circulation, Deep-Sea Res. Pt. II, 58, 1744–1753, https://doi.org/10.1016/j.dsr2.2010.10.056, 2011.
Roberts, C. D., Waters, J., Peterson, K. A., Palmer, M., McCarthy, G. D., Frajka-Williams, E., Haines, K., Lea, D. J., Martin, M. J., Storkey, D., Blockley, E. W., and Zuo, H.: Atmosphere drives observed interannual variability of the Atlantic meridional overturning circulation at 26.5° N, Geophys. Res. Lett., 40, 5164–5170, https://doi.org/10.1002/grl.50930, 2013.
Roberts, C. D., Jackson, L., and McNeall, D.: Is the 2004–2012 reduction of the Atlantic meridional overturning circulation significant?, Geophys. Res. Lett., 41, 3204–3210, https://doi.org/10.1002/2014GL059473, 2014.
Robson, J., Hodson, D., Hawkins, E., and Sutton, R.: Atlantic overturning in decline?, Nat. Geosci., 7, 2–3, https://doi.org/10.1038/ngeo2050, 2014.
Rousset, C. and Beal, L. M.: Closing the transport budget of the Florida Straits, Geophys. Res. Lett., 41, 2460–2466, https://doi.org/10.1002/2014GL059498, 2014.
Smeed, D. A., McCarthy, G. D., Cunningham, S. A., Frajka-Williams, E., Rayner, D., Johns, W. E., Meinen, C. S., Baringer, M. O., Moat, B. I., Duchez, A., and Bryden, H. L.: Observed decline of the Atlantic meridional overturning circulation 2004–2012, Ocean Sci., 10, 29–38, https://doi.org/10.5194/os-10-29-2014, 2014.
Smeed, D. A., McCarthy, G., Rayner, D., Moat, B. I., Johns, W. E., Baringer, M. O., and Meinen, C. S.: Atlantic meridional overturning circulation observed by the RAPID-MOCHA-WBTS (RAPID-Meridional Overturning Circulation and Heatflux Array-Western Boundary Time Series) array at 26° N from 2004 to 2014, available at: https://www.bodc.ac.uk/data/published_data_library/catalogue/10.5285/1a774e53-7383-2e9a-e053-6c86abc0d8c7/, last access: 15 August 2015.
Thomas, M. D. and Zhai, X.: Eddy-induced variability of the meridional overturning circulation in a model of the North Atlantic, Geophys. Res. Lett., 40, 2742–2747, https://doi.org/10.1002/grl.50532, 2013.
Wunsch, C.: Mass and volume transport variability in an eddy-filled ocean, Nat. Geosci., 1, 165–168, https://doi.org/10.1038/ngeo126, 2008.
Wunsch, C. and Heimbach, P.: Two decades of the Atlantic meridional overturning circulation: Anatomy, variations, extremes, prediction, and overcoming its limitations, J. Climate, 26, 7167–7186, https://doi.org/10.1175/JCLI-D-12-00478.1, 2013.
Xu, X., Chassignet, E. P., Johns, W. E., Schmitz Jr., W. J., and Metzger, E. J.: Intraseasonal to interannual variability of the Atlantic meridional overturning circulation from eddy-resolving simulations and observations, J. Geophys. Res., 119, 5140–5159, https://doi.org/10.1002/2014JC009994, 2014.
Yang, J.: Local and remote wind stress forcing of the seasonal variability of the Atlantic Meridional Overturning Circulation (AMOC) transport at 26.5° N, J. Geophys. Res., 120, 2488–2503, https://doi.org/10.1002/2014JC010317, 2015.
Yeager, S.: Topographic coupling of the Atlantic overturning and gyre circulations, J. Phys. Oceanogr., 45, 1258–1284, https://doi.org/10.1175/JPO-D-14-0100.1, 2015.
Zhao, J. and Johns, W.: Wind-forced interannual variability of the Atlantic Meridional Overturning Circulation at 26.5° N, J. Geophys. Res., 119, 2403–2419, https://doi.org/10.1002/2013JC009407, 2014.
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.
The ocean meridional overturning circulation (MOC) is predicted by climate models to slow down...