Articles | Volume 20, issue 3
https://doi.org/10.5194/os-20-799-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-20-799-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
18 Jun 2024
Research article |
| 18 Jun 2024
| 18 Jun 2024
Observed change and the extent of coherence in the Gulf Stream system
Geophysical Institute, University of Bergen, Bergen, Norway
Bjerknes Centre for Climate Research, Bergen, Norway
Tor Eldevik
Geophysical Institute, University of Bergen, Bergen, Norway
Bjerknes Centre for Climate Research, Bergen, Norway
Johanne Skrefsrud
Geophysical Institute, University of Bergen, Bergen, Norway
Bjerknes Centre for Climate Research, Bergen, Norway
Helen L. Johnson
Department of Earth Sciences, University of Oxford, Oxford, UK
Alejandra Sanchez-Franks
National Oceanography Centre, Southampton, UK
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Harry Ashton-Key, Jennifer Mecking, Robert Marsh, Sybren Drijfhout, Marilena Oltmanns, and Alejandra Sanchez-Franks
EGUsphere, https://doi.org/10.5194/egusphere-2026-575, https://doi.org/10.5194/egusphere-2026-575, 2026
This preprint is open for discussion and under review for Ocean Science (OS).
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The North Atlantic ocean circulation is expected to weaken due to climate change. First signs of weakening are expected in the subpolar north, reverberating equatorward over years to decades, with unfolding consequences for the climate of Europe and beyond. As the pattern of weakening may provide an early warning of several years, we scrutinise leading climate models to show that the location and degree of weakening strongly depends on the model type and extent of climate change.
Oliver J. Tooth, Helen L. Johnson, and Chris Wilson
Ocean Sci., 21, 2101–2123, https://doi.org/10.5194/os-21-2101-2025, https://doi.org/10.5194/os-21-2101-2025, 2025
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The North Atlantic subpolar gyre (SPG) forms dense water as part of the Atlantic Meridional Overturning Circulation. To explore the factors controlling dense-water formation around the SPG, we trace the pathways of virtual water parcels in a high-resolution ocean model. We show that the amount of dense water formed around the SPG depends principally on the availability of light waters flowing northward, such that a stronger SPG circulation results in more dense-water formation along-stream.
Peter M. F. Sheehan, Benjamin G. M. Webber, Alejandra Sanchez-Franks, and Bastien Y. Queste
Ocean Sci., 21, 1575–1588, https://doi.org/10.5194/os-21-1575-2025, https://doi.org/10.5194/os-21-1575-2025, 2025
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Using measurements and computer models, we identify a large flux of oxygen within the Southwest Monsoon Current, which flows north into the Bay of Bengal between June and September each year. Oxygen levels in the bay are very low, but they are not quite low enough for key nutrient cycles to be as dramatically altered as in other low-oxygen regions. We suggest that the flux which we identify contributes to keeping oxygen levels in the bay above the threshold below which dramatic changes would occur.
Yavor Kostov, Marie-José Messias, Herlé Mercier, David P. Marshall, and Helen L. Johnson
Ocean Sci., 20, 521–547, https://doi.org/10.5194/os-20-521-2024, https://doi.org/10.5194/os-20-521-2024, 2024
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We examine factors affecting variability in the volume of Labrador Sea Water (LSW), a water mass that is important for the uptake and storage of heat and carbon in the Atlantic Ocean. We find that LSW accumulated in the Labrador Sea exhibits a lagged response to remote conditions: surface wind stress, heat flux, and freshwater flux anomalies, especially along the pathways of the North Atlantic Current branches. We use our results to reconstruct and attribute historical changes in LSW volume.
Oliver John Tooth, Helen Louise Johnson, Chris Wilson, and Dafydd Gwyn Evans
Ocean Sci., 19, 769–791, https://doi.org/10.5194/os-19-769-2023, https://doi.org/10.5194/os-19-769-2023, 2023
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This study uses the trajectories of water parcels traced within an ocean model simulation to identify the pathways responsible for the seasonal cycle of dense water formation (overturning) in the eastern subpolar North Atlantic. We show that overturning seasonality is due to the fastest water parcels circulating within the eastern basins in less than 8.5 months. Slower pathways set the average strength of overturning in this region since water parcels cannot escape intense wintertime cooling.
Bjørg Risebrobakken, Mari F. Jensen, Helene R. Langehaug, Tor Eldevik, Anne Britt Sandø, Camille Li, Andreas Born, Erin Louise McClymont, Ulrich Salzmann, and Stijn De Schepper
Clim. Past, 19, 1101–1123, https://doi.org/10.5194/cp-19-1101-2023, https://doi.org/10.5194/cp-19-1101-2023, 2023
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In the observational period, spatially coherent sea surface temperatures characterize the northern North Atlantic at multidecadal timescales. We show that spatially non-coherent temperature patterns are seen both in further projections and a past warm climate period with a CO2 level comparable to the future low-emission scenario. Buoyancy forcing is shown to be important for northern North Atlantic temperature patterns.
Noam S. Vogt-Vincent, Satoshi Mitarai, and Helen L. Johnson
EGUsphere, https://doi.org/10.5194/egusphere-2023-778, https://doi.org/10.5194/egusphere-2023-778, 2023
Preprint archived
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Coral larvae can drift through ocean currents between coral reefs, establishing connectivity, which plays an important role in coral reef resilience. However, larval transport is chaotic. We simulate coral spawning events across the tropical southwest Indian Ocean for almost three decades, and find that larval transport can vary massively from day-to-day. This variability is largely random, and this introduces a lot of uncertainty in connectivity predictions.
Noam S. Vogt-Vincent and Helen L. Johnson
Geosci. Model Dev., 16, 1163–1178, https://doi.org/10.5194/gmd-16-1163-2023, https://doi.org/10.5194/gmd-16-1163-2023, 2023
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Ocean currents transport things over large distances across the ocean surface. Predicting this transport is key for tackling many environmental problems, such as marine plastic pollution and coral reef resilience. However, doing this requires a good understanding ocean currents, which is currently lacking. Here, we present and validate state-of-the-art simulations for surface currents in the southwestern Indian Ocean, which will support future marine dispersal studies across this region.
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.
Helen E. Phillips, Amit Tandon, Ryo Furue, Raleigh Hood, Caroline C. Ummenhofer, Jessica A. Benthuysen, Viviane Menezes, Shijian Hu, Ben Webber, Alejandra Sanchez-Franks, Deepak Cherian, Emily Shroyer, Ming Feng, Hemantha Wijesekera, Abhisek Chatterjee, Lisan Yu, Juliet Hermes, Raghu Murtugudde, Tomoki Tozuka, Danielle Su, Arvind Singh, Luca Centurioni, Satya Prakash, and Jerry Wiggert
Ocean Sci., 17, 1677–1751, https://doi.org/10.5194/os-17-1677-2021, https://doi.org/10.5194/os-17-1677-2021, 2021
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Over the past decade, understanding of the Indian Ocean has progressed through new observations and advances in theory and models of the oceanic and atmospheric circulation. This review brings together new understanding of the ocean–atmosphere system in the Indian Ocean, describing Indian Ocean circulation patterns, air–sea interactions, climate variability, and the critical role of the Indian Ocean as a clearing house for anthropogenic heat.
Ingo Bethke, Yiguo Wang, François Counillon, Noel Keenlyside, Madlen Kimmritz, Filippa Fransner, Annette Samuelsen, Helene Langehaug, Lea Svendsen, Ping-Gin Chiu, Leilane Passos, Mats Bentsen, Chuncheng Guo, Alok Gupta, Jerry Tjiputra, Alf Kirkevåg, Dirk Olivié, Øyvind Seland, Julie Solsvik Vågane, Yuanchao Fan, and Tor Eldevik
Geosci. Model Dev., 14, 7073–7116, https://doi.org/10.5194/gmd-14-7073-2021, https://doi.org/10.5194/gmd-14-7073-2021, 2021
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The Norwegian Climate Prediction Model version 1 (NorCPM1) is a new research tool for performing climate reanalyses and seasonal-to-decadal climate predictions. It adds data assimilation capability to the Norwegian Earth System Model version 1 (NorESM1) and has contributed output to the Decadal Climate Prediction Project (DCPP) as part of the sixth Coupled Model Intercomparison Project (CMIP6). We describe the system and evaluate its baseline, reanalysis and prediction performance.
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.
Jack Giddings, Karen J. Heywood, Adrian J. Matthews, Manoj M. Joshi, Benjamin G. M. Webber, Alejandra Sanchez-Franks, Brian A. King, and Puthenveettil N. Vinayachandran
Ocean Sci., 17, 871–890, https://doi.org/10.5194/os-17-871-2021, https://doi.org/10.5194/os-17-871-2021, 2021
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Little is known about the impact of chlorophyll on SST in the Bay of Bengal (BoB). Solar irradiance measured by an ocean glider and three Argo floats is used to determine the effect of chlorophyll on BoB SST during the 2016 summer monsoon. The Southwest Monsoon Current has high chlorophyll concentrations (∼0.5 mg m−3) and shallow solar penetration depths (∼14 m). Ocean mixed layer model simulations show that SST increases by 0.35°C per month, with the potential to influence monsoon rainfall.
Cited articles
Årthun, M., Eldevik, T., Viste, E., Drange, H., Furevik, T., Johnson, H. L., and Keenlyside, N. S.: Skillful prediction of northern climate provided by the ocean, Nat. Commun., 8, 15875, https://doi.org/10.1038/ncomms15875, 2017. a
Årthun, M., Asbjørnsen, H., Chafik, L., Johnson, H. L., and Våge, K.: Future strengthening of the Nordic Seas overturning circulation, Nat. Commun., 14, 2065, https://doi.org/10.1038/s41467-023-37846-6, 2023. a
Asbjørnsen, H. and Årthun, M.: Deconstructing Future AMOC Decline at 26.5°N, Geophys. Res. Lett., 50, e2023GL103515, https://doi.org/10.1029/2023GL103515, 2023. a, b
Asbjørnsen, H., Årthun, M., Skagseth, Ø., and Eldevik, T.: Mechanisms of ocean heat anomalies in the Norwegian Sea, J. Geophys. Res.-Oceans, 124, 2908–2923, https://doi.org/10.1029/2018JC014649, 2019. a, b
Asbjørnsen, H., Johnson, H. L., and Årthun, M.: Variable Nordic Seas inflow linked to shifts in North Atlantic circulation, J. Climate, 34, 1–50, https://doi.org/10.1175/JCLI-D-20-0917.1, 2021. a
Baehr, J., Keller, K., and Marotzke, J.: Detecting potential changes in the meridional overturning circulation at 26˚N in the Atlantic, Climatic Change, 91, 11–27, https://doi.org/10.1007/s10584-006-9153-z, 2008. a, b
Baringer, M. O. and Larsen, J. C.: Sixteen years of Florida Current Transport at 27°N, Geophys. Res. Lett., 28, 3179–3182, https://doi.org/10.1029/2001GL013246, 2001. a, b
Beadling, R. L., Russell, J. L., Stouffer, R. J., and Goodman, P. J.: Evaluation of Subtropical North Atlantic Ocean Circulation in CMIP5 Models against the Observational Array at 26.5°N and Its Changes under Continued Warming, J. Climate, 31, 9697–9718, https://doi.org/10.1175/JCLI-D-17-0845.1, 2018. a
Berx, B., Hansen, B., Østerhus, S., Larsen, K. M., Sherwin, T., and Jochumsen, K.: Combining in situ measurements and altimetry to estimate volume, heat and salt transport variability through the Faroe–Shetland Channel, Ocean Sci., 9, 639–654, https://doi.org/10.5194/os-9-639-2013, 2013. a
Bingham, R. J., Hughes, C. W., Roussenov, V., and Williams, R. G.: Meridional coherence of the North Atlantic meridional overturning circulation, Geophys. Res. Lett., 34, L23606, https://doi.org/10.1029/2007GL031731, 2007. a, b, c
Brambilla, E., Talley, L. D., and Robbins, P. E.: Subpolar Mode Water in the northeastern Atlantic: 2. Origin and transformation, J. Geophys. Res., 113, C04026, https://doi.org/10.1029/2006JC004063, 2008. a
Bringedal, C., Eldevik, T., Skagseth, Ø., Spall, M. A., and Østerhus, S.: Structure and Forcing of Observed Exchanges across the Greenland-Scotland Ridge, J. Climate, 31, 9881–9901, https://doi.org/10.1175/JCLI-D-17-0889.1, 2018. a
Caesar, L., Rahmstorf, S., Robinson, A., Feulner, G., and Saba, V.: Observed fingerprint of a weakening Atlantic Ocean overturning circulation, Nature, 556, 191–196, https://doi.org/10.1038/s41586-018-0006-5, 2018. a
Caesar, L., McCarthy, G. D., Thornalley, D. J. R., Cahill, N., and Rahmstorf, S.: Current Atlantic Meridional Overturning Circulation weakest in last millennium, Nat. Geosci., 14, 118–120, https://doi.org/10.1038/s41561-021-00699-z, 2021. a
Caínzos, V., Hernández‐Guerra, A., McCarthy, G. D., McDonagh, E. L., Armas, M. C., and Pérez-Hernández, M. D.: Thirty years of GOSHIP and WOCE data: Atlantic Overturning of mass, heat and freshwater transport, Geophys. Res. Lett., 49, e2021GL096527, https://doi.org/10.1029/2021GL096527, 2022. a
Chafik, L.: The response of the circulation in the Faroe-Shetland Channel to the North Atlantic Oscillation, Tellus, 64, 18423, https://doi.org/10.3402/tellusa.v64i0.18423, 2012. a
Chelton, D. B.: Effects of sampling errors in statistical estimation, Deep-Sea Res. Pt. I, 30, 1083–1103, https://doi.org/10.1016/0198-0149(83)90062-6, 1983. a, b
Chi, L., Wolfe, C. L., and Hameed, S.: Reconsidering the Relationship Between Gulf Stream Transport and Dynamic Sea Level at U.S. East Coast, Geophys. Res. Lett., 50, e2022GL102018, https://doi.org/10.1029/2022GL102018, 2023. a
Cunningham, S. A., Kanzow, T., Rayner, D., Baringer, M. O., Johns, W. E., Marotzke, J., Longworth, H. R., Grant, E. M., J-M Hirschi, J., Beal, L. M., Meinen, C. S., and Bryden, H. L.: Temporal Variability of the Atlantic Meridional Overturning Circulation at 26.5°N, Science, 317, 935–937, https://doi.org/10.1126/science.1141304, 2007. a, b, c
Daniault, N., Mercier, H., Lherminier, P., Sarafanov, A., Falina, A., Zunino, P., Pérez, F. F., Ríos, A. F., Ferron, B., Huck, T., Thierry, V., and Gladyshev, S.: The northern North Atlantic Ocean mean circulation in the early 21st century, Prog. Oceanogr., 146, 142–158, https://doi.org/10.1016/J.POCEAN.2016.06.007, 2016. a
Desbruyères, D., Chafik, L., and Maze, G.: A shift in the ocean circulation has warmed the subpolar North Atlantic Ocean since 2016, Commun. Earth Environ., 2, 48, https://doi.org/10.1038/s43247-021-00120-y, 2021. a
Dong, S., Volkov, D. L., Goni, G., Pujiana, K., Tagklis, F., and Baringer, M.: Remote Impact of the Equatorial Pacific on Florida Current Transport, Geophys. Res. Lett., 49, e2021GL096944, https://doi.org/10.1029/2021GL096944, 2022. a
Ebisuzaki, W.: A Method to Estimate the Statistical Significance of a Correlation When the Data Are Serially Correlated, J. Climate, 10, 2147–2153, https://doi.org/10.1175/1520-0442(1997)010<2147:AMTETS>2.0.CO;2, 1997. a, b
ECCO Consortium, Fukumori, I., Wang, O., Fenty, I., Forget, G., Heimbach, P., and Ponte, R. M.: Synopsis of the ECCO Central Production Global Ocean and Sea-Ice State Estimate, Version 4 Release 4, Zenodo, https://doi.org/10.5281/zenodo.3765928, 2021. a, b
Eden, C. and Willebrand, J.: Mechanism of Interannual to Decadal Variability of the North Atlantic Circulation, J. Climate, 14, 2266–2280, https://doi.org/10.1175/1520-0442(2001)014<2266:MOITDV>2.0.CO;2, 2001. a, b, c
Evans, D. G., Toole, J., Forget, G., Zika, J. D., Naveira Garabato, A. C., Nurser, A. J. G., and Yu, L.: Recent Wind-Driven Variability in Atlantic Water Mass Distribution and Meridional Overturning Circulation, J. Phys. Oceanogr., 47, 633–647, https://doi.org/10.1175/JPO-D-16-0089.1, 2017. a
Flagg, C. N., Schwartze, G., Gottlieb, E., and Rossby, T.: Operating an Acoustic Doppler Current Profiler aboard a Container Vessel, J. Atmos. Ocean. Tech., 15, 257–271, https://doi.org/10.1175/1520-0426(1998)015<0257:OAADCP>2.0.CO;2, 1998. a
Forget, G., Campin, J.-M., Heimbach, P., Hill, C. N., Ponte, R. M., and Wunsch, C.: ECCO version 4: an integrated framework for non-linear inverse modeling and global ocean state estimation, Geosci. Model Dev., 8, 3071–3104, https://doi.org/10.5194/gmd-8-3071-2015, 2015. a
Fox, A. D., Handmann, P., Schmidt, C., Fraser, N., Rühs, S., Sanchez-Franks, A., Martin, T., Oltmanns, M., Johnson, C., Rath, W., Holliday, N. P., Biastoch, A., Cunningham, S. A., and Yashayaev, I.: Exceptional freshening and cooling in the eastern subpolar North Atlantic caused by reduced Labrador Sea surface heat loss, Ocean Sci., 18, 1507–1533, https://doi.org/10.5194/os-18-1507-2022, 2022. a
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. a
Frajka-Williams, E., Ansorge, I. J., Baehr, J., Bryden, H. L., Chidichimo, M. P., Cunningham, S. A., Danabasoglu, G., Dong, S., Donohue, K. A., Elipot, S., Heimbach, P., Holliday, N. P., Hummels, R., Jackson, L. C., Karstensen, J., Lankhorst, M., Le Bras, I. A., Lozier, M. S., McDonagh, E. L., Meinen, C. S., Mercier, H., Moat, B. I., Perez, R. C., Piecuch, C. G., Rhein, M., Srokosz, M. A., Trenberth, K. E., Bacon, S., Forget, G., Goni, G., Kieke, D., Koelling, J., Lamont, T., McCarthy, G. D., Mertens, C., Send, U., Smeed, D. A., Speich, S., van den Berg, M., Volkov, D., and Wilson, C.: Atlantic Meridional Overturning Circulation: Observed Transport and Variability, Front. Mar. Sci., 6, 260, https://doi.org/10.3389/fmars.2019.00260, 2019. a
Frajka-Williams, E., Foukal, N., and Danabasoglu, G.: Should AMOC observations continue: how and why?, Philosophical Transactions of the Royal Society A, 381, https://doi.org/10.1098/RSTA.2022.0195, 2023. a
Fraser, N. J. and Cunningham, S. A.: 120 years of AMOC variability reconstructed from observations using the Bernoulli inverse, Geophys. Res. Lett., 48, e2021GL093893, https://doi.org/10.1029/2021GL093893, 2021. a, b
Fu, Y., Li, F., Karstensen, J., and Wang, C.: A stable Atlantic Meridional Overturning Circulation in a changing North Atlantic Ocean since the 1990s, Sci. Adv., 6, 7836–7863, 2020. a
Fu, Y., Lozier, M. S., Biló, T. C., Bower, A. S., Cunningham, S. A., Cyr, F., de Jong, M. F., deYoung, B., Drysdale, L., Fraser, N., Fried, N., Furey, H. H., Han, G., Handmann, P., Holliday, N. P., Holte, J., Inall, M. E., Johns, W. E., Jones, S., Karstensen, J., Li, F., Pacini, A., Pickart, R. S., Rayner, D., Straneo, F., and Yashayaev, I.: Seasonality of the Meridional Overturning Circulation in the subpolar North Atlantic, Commun. Earth Environ., 4, 181, https://doi.org/10.1038/s43247-023-00848-9, 2023a. a, b, c
Fu, Y., Lozier, M. S., Biló, T., Bower A., Cunningham, S., Cyr, F., de Jong, M., deYoung, B., Drysdale, L., Fraser, N., Fried, N., Furey, H., Han, G., Handmann, P., Holliday, N., Holte, J., Inall, M., Johns, W., Jones, S., Karstensen, J., Li, F., Pacini, A., Pickart, R., Rayner, D., Straneo, F., and Yashayaev, I.: Meridional Overturning Circulation Observed by the Overturning in the Subpolar North Atlantic Program (OSNAP) Array from August 2014 to June 2020, Georgia Tech Digital Repository [data set], https://doi.org/10.35090/gatech/70342, 2023b. a
Gu, S., Liu, Z., and Wu, L.: Time Scale Dependence of the Meridional Coherence of the Atlantic Meridional Overturning Circulation, J. Geophys. Res.-Oceans, 125, e2019JC015838, https://doi.org/10.1029/2019JC015838, 2020. a, b
Hamed, K. H. and Rao, R. A.: A modified Mann-Kendall trend test for autocorrelated data, J. Hydrol., 204, 182–196, https://doi.org/10.1016/S0022-1694(97)00125-X, 1997. a, b
Hameed, S., Wolfe, C. L. P., and Chi, L.: Icelandic Low and Azores High Migrations Impact Florida Current Transport in Winter, J. Phys. Oceanogr., 51, 3135–3147, https://doi.org/10.1175/JPO-D-20-0108.1, 2021. a, b
Han, L.: Exploring the AMOC Connectivity Between the RAPID and OSNAP Lines With a Model-Based Data Set, Geophys. Res. Lett., 50, e2023GL105225, https://doi.org/10.1029/2023GL105225, 2023. a
Hansen, B., Larsen, K. M. H., Hátún, H., Kristiansen, R., Mortensen, E., and Østerhus, S.: Transport of volume, heat, and salt towards the Arctic in the Faroe Current 1993–2013, Ocean Sci., 11, 743–757, https://doi.org/10.5194/os-11-743-2015, 2015. a
Hansen, B., Húsgarð Larsen, K. M., Hátún, H., and Østerhus, S.: A stable Faroe Bank Channel overflow 1995–2015, Ocean Sci., 12, 1205–1220, https://doi.org/10.5194/os-12-1205-2016, 2016. a
Heimbach, P., Hill, C., and Giering, R.: An efficient exact adjoint of the parallel MIT General Circulation Model, generated via automatic differentiation, Future Gener. Comp. Sy., 21, 1356–1371, https://doi.org/10.1016/J.FUTURE.2004.11.010, 2005. a
Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A., Muñoz‐Sabater, J., Nicolas, J., Peubey, C., Radu, R., Schepers, D., Simmons, A., Soci, C., Abdalla, S., Abellan, X., Balsamo, G., Bechtold, P., Biavati, G., Bidlot, J., Bonavita, M., Chiara, G., Dahlgren, P., Dee, D., Diamantakis, M., Dragani, R., Flemming, J., Forbes, R., Fuentes, M., Geer, A., Haimberger, L., Healy, S., Hogan, R. J., Hólm, E., Janisková, M., Keeley, S., Laloyaux, P., Lopez, P., Lupu, C., Radnoti, G., Rosnay, P., Rozum, I., Vamborg, F., Villaume, S., and Thépaut, J.: The ERA5 global reanalysis, Q. J. Roy. Meteor. Soc., 146, 1999–2049, https://doi.org/10.1002/qj.3803, 2020. a, b
Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., Thépaut, J.-N.: ERA5 monthly averaged data on single levels from 1940 to present, Copernicus Climate Change Service (C3S) Climate Data Store (CDS) [data set], https://doi.org/10.24381/cds.f17050d7, 2023. a
Hirschi, J. J.-M., Frajka-Williams, E., Blaker, A. T., Sinha, B., Coward, A., Hyder, P., Biastoch, A., Böning, C., Barnier, B., Penduff, T., Garcia, I., Fransner, F., and Madec, G.: Loop Current Variability as Trigger of Coherent Gulf Stream Transport Anomalies, J. Phys. Oceanogr., 49, 2115–2132, https://doi.org/10.1175/JPO-D-18-0236.1, 2019. a
Hogg, N. G.: On the transport of the Gulf Stream between Cape Hatteras and the Grand Banks, Deep-Sea Res. Pt. I, 39, 1231–1246, https://doi.org/10.1016/0198-0149(92)90066-3, 1992. a
Ingvaldsen, R. B., Loeng, H., and Asplin, L.: Variability in the Atlantic inflow to the Barents Sea based on a one-year time series from moored current meters, Cont. Shelf Res., 22, 505–519, https://doi.org/10.1016/S0278-4343(01)00070-X, 2002. a
Ingvaldsen, R. B., Asplin, L., and Loeng, H.: Velocity field of the western entrance to the Barents Sea, J. Geophys. Res.-Oceans, 109, C03021, https://doi.org/10.1029/2003JC001811, 2004. a, b, c
Ingvaldsen, R.: Mooring data from the Barents Sea Opening – Atlantic Water inflow, Norwegian Marine Data Centre [data set], https://doi.org/10.21335/NMDC-1838527821, 2020. a
Jackson, L. C., Biastoch, A., Buckley, M. W., Desbruyères, D. G., Frajka-Williams, E., Moat, B., and Robson, J.: The evolution of the North Atlantic Meridional Overturning Circulation since 1980, Nat. Rev. Earth Environ., 3, 241–254, https://doi.org/10.1038/s43017-022-00263-2, 2022. a, b, c, d
Jochumsen, K., Moritz, M., Nunes, N., Quadfasel, D., Larsen, K. M., Hansen, B., Valdimarsson, H., and Jonsson, S.: Revised transport estimates of the Denmark Strait overflow, J. Geophys. Res.-Oceans, 122, 3434–3450, https://doi.org/10.1002/2017JC012803, 2017. a
Johnson, H. L. and Marshall, D. P.: A Theory for the Surface Atlantic Response to Thermohaline Variability, J. Phys. Oceanogr., 32, 1121–1132, https://doi.org/10.1175/1520-0485(2002)032<1121:ATFTSA>2.0.CO;2, 2002. a
Jónsson, S. and Valdimarsson, H.: Water mass transport variability to the North Icelandic shelf, 1994–2010, ICES J. Mar. Sci., 69, 809–815, https://doi.org/10.1093/icesjms/fss024, 2012. a
Keenlyside, N. S., Latif, M., Jungclaus, J., Kornblueh, L., and Roeckner, E.: Advancing decadal-scale climate prediction in the North Atlantic sector, Nat. Geosci., 453, 84–88, https://doi.org/10.1038/nature06921, 2008. a
Kelson, R. L., Straub, D. N., and Dufour, C. O.: Using CMIP6 models to assess the significance of the observed trend in the Atlantic Meridional Overturning Circulation, Geophys. Res. Lett.49, 49, e2022GL100202, https://doi.org/10.1029/2022GL100202, 2022. a
Kilbourne, K. H., Wanamaker, A. D., Moffa-Sanchez, P., Reynolds, D. J., Amrhein, D. E., Butler, P. G., Gebbie, G., Goes, M., Jansen, M. F., Little, C. M., Mette, M., Moreno-Chamarro, E., Ortega, P., Otto-Bliesner, B. L., Rossby, T., Scourse, J., and Whitney, N. M.: Atlantic circulation change still uncertain, Nat. Geosci., 15, 165–167, https://doi.org/10.1038/s41561-022-00896-4, 2022. a
Kostov, Y., Johnson, H. L., Marshall, D. P., Heimbach, P., Forget, G., Holliday, N. P., Lozier, M. S., Li, F., Pillar, H. R., and Smith, T.: Distinct sources of interannual subtropical and subpolar Atlantic overturning variability, Nat. Geosci., 14, 491–495, https://doi.org/10.1038/s41561-021-00759-4, 2021. a, b, c
Koul, V., Tesdal, J.-E., Bersch, M., Hátún, H., Brune, S., Borchert, L., Haak, H., Schrum, C., and Baehr, J.: Unraveling the choice of the north Atlantic subpolar gyre index, Sci. Rep., 10, 1005, https://doi.org/10.1038/s41598-020-57790-5, 2020. a, b
Kwon, Y.-O., Alexander, M. A., Bond, N. A., Frankignoul, C., Nakamura, H., Qiu, B., and Thompson, L. A.: Role of the Gulf Stream and Kuroshio–Oyashio Systems in Large-Scale Atmosphere–Ocean Interaction: A Review, J. Climate, 23, 3249–3281, https://doi.org/10.1175/2010JCLI3343.1, 2010. a
Larsen, J. C. and Sanford, T. B.: Florida Current Volume Transports from Voltage Measurements, Science, 227, 302–304, https://doi.org/10.1126/science.227.4684.302, 1985. a
Li, F., Lozier, M. S., and Johns, W. E.: Calculating the Meridional Volume, Heat, and Freshwater Transports from an Observing System in the Subpolar North Atlantic: Observing System Simulation Experiment, J. Atmos. Ocean. Tech., 34, 1483–1500, https://doi.org/10.1175/JTECH-D-16-0247.1, 2017. a
Lique, C. and Thomas, M. D.: Latitudinal shift of the Atlantic Meridional Overturning Circulation source regions under a warming climate, Nat. Clim. Change, 8, 1013–1020, https://doi.org/10.1038/s41558-018-0316-5, 2018. a
Lobelle, D., Beaulieu, C., Livina, V., Sévellec, F., and Frajka-Williams, E.: Detectability of an AMOC Decline in Current and Projected Climate Changes, Geophys. Res. Lett., 47, e2020GL089974, https://doi.org/10.1029/2020GL089974, 2020. a
Lozier, M. S.: Deconstructing the Conveyor Belt, Science, 328, 1507–1511, https://doi.org/10.1126/science.1189250, 2010. a
Lozier, M. S.: Overturning in the North Atlantic, Annu. Rev. Mar. Sci., 4, 291–315, https://doi.org/10.1146/annurev-marine-120710-100740, 2012. a
Lozier, M. S., Roussenov, V., Reed, M. S. C., and Williams, R. G.: Opposing decadal changes for the North Atlantic meridional overturning circulation, Nat. Geosci., 3, 728–734, https://doi.org/10.1038/ngeo947, 2010. a, b, c
Lozier, S., Bacon, S., Bower, A. S., Cunningham, S. A., Femke de Jong, M., de Steur, L., deYoung, B., Fischer, J., Gary, S. F., Greenan, B. J. W., Heimbach, P., Holliday, N. P., Houpert, L., Inall, M. E., Johns, W. E., Johnson, H. L., Karstensen, J., Li, F., Lin, X., Mackay, N., Marshall, D. P., Mercier, H., Myers, P. G., Pickart, R. S., Pillar, H. R., Straneo, F., Thierry, V., Weller, R. A., Williams, R. G., Wilson, C., Yang, J., Zhao, J., and Zika, J. D.: Overturning in the Subpolar North Atlantic Program: A New International Ocean Observing System, Bulletin of the American Meteorological Society, 98, 737–752, https://doi.org/10.1175/BAMS-D-16-0057.1, 2017. a, b, c
Manabe, S. and Stouffer, R. J.: Multiple-Century Response of a Coupled Ocean-Atmosphere Model to an Increase of Atmospheric Carbon Dioxide, J. Climate, 7, 5–23, https://doi.org/10.1175/1520-0442(1994)007<0005:MCROAC>2.0.CO;2, 1994. a
Mann, C.: The termination of the Gulf Stream and the beginning of the North Atlantic Current, Deep-Sea Res., 14, 337–359, https://doi.org/10.1016/0011-7471(67)90077-0, 1967. a
Marshall, J., Johnson, H., and Goodman, J.: A Study of the Interaction of the North Atlantic Oscillation with Ocean Circulation, J. Climate, 14, 1399–1421, https://doi.org/10.1175/1520-0442(2001)014<1399:ASOTIO>2.0.CO;2, 2001. a, b, c
Marshall, D. P. and Johnson, H. L.: Propagation of Meridional Circulation Anomalies along Western and Eastern Boundaries, J. Phys. Oceanogr., 43, 2699–2717, https://doi.org/10.1175/JPO-D-13-0134.1, 2013. a
Mauritzen, C.: Production of dense overflow waters feeding the North Atlantic across the Greenland-Scotland Ridge. Part 1: Evidence for a revised circulation scheme, Deep-Sea Res. Pt. I, 43, 769–806, https://doi.org/10.1016/0967-0637(96)00037-4, 1996. a
McCarthy, G. D., Smeed, D. A., Johns, W. E., Frajka-Williams, E., Moat, B. I., Rayner, D., Baringer, M. O., Meinen, C. S., Collins, J., and Bryden, H.: 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. a, b
Meinen, C. S. and Watts, D. R.: Vertical structure and transport on a transect across the North Atlantic Current near 42°N: Time series and mean, J. Geophys. Res.-Oceans, 105, 21869–21891, https://doi.org/10.1029/2000JC900097, 2000. a
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, https://doi.org/10.1016/J.DSR.2010.04.001, 2010 (data available at: https://www.aoml.noaa.gov/phod/floridacurrent/, last access: 4 June 2024). a, b, c
Meinen, C. S., Johns, W. E., Moat, B. I., Smith, R. H., Johns, E. M., Rayner, D., Frajka-Williams, E., Garcia, R. F., and Garzoli, S. L.: Structure and Variability of the Antilles Current at 26.5°N, J. Geophys. Res.-Oceans, 124, 3700–3723, https://doi.org/10.1029/2018JC014836, 2019. a
Mercier, H., Lherminier, P., Sarafanov, A., Gaillard, F., Daniault, N., Desbruyères, D., Falina, A., Ferron, B., Gourcuff, C., Huck, T., and Thierry, V.: Variability of the meridional overturning circulation at the Greenland–Portugal OVIDE section from 1993 to 2010, Prog. Oceanogr., 132, 250–261, https://doi.org/10.1016/J.POCEAN.2013.11.001, 2015. a
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. a, b
Moat, B. I., Smeed, D. A., Frajka-Williams, E., Desbruyères, D. G., Beaulieu, C., Johns, W. E., Rayner, D., Sanchez-Franks, A., Baringer, M. O., Volkov, D., Jackson, L. C., and Bryden, H. L.: Pending recovery in the strength of the meridional overturning circulation at 26° N, Ocean Sci., 16, 863–874, https://doi.org/10.5194/os-16-863-2020, 2020. a, b, c, d
Moat, B. I., Frajka-Williams, E., Rayner, D., Johns, W. E., Baringer, M. O., Volkov, D. L., and Collins, J.: Atlantic meridional overturning circulation observed by the RAPID-MOCHA-WBTS array at 26N from 2004 to 2020 (v2020.2), NERC EDS British Oceanographic Data Centre NOC [data set], https://doi.org/10.5285/e91b10af-6f0a-7fa7-e053-6c86abc05a09, 2022. a
Moffa‐Sánchez, P., Moreno‐Chamarro, E., Reynolds, D. J., Ortega, P., Cunningham, L., Swingedouw, D., Amrhein, D. E., Halfar, J., Jonkers, L., Jungclaus, J. H., Perner, K., Wanamaker, A., and Yeager, S.: Variability in the Northern North Atlantic and Arctic Oceans Across the Last Two Millennia: A Review, Paleoceanogr. Paleocl. 34, 1399–1436, https://doi.org/10.1029/2018PA003508, 2019. a
Orvik, K. A.: Long‐Term Moored Current and Temperature Measurements of the Atlantic Inflow Into the Nordic Seas in the Norwegian Atlantic Current; 1995–2020, Geophys. Res. Lett., 49, e2021GL096427, https://doi.org/10.1029/2021GL096427, 2022. a, b, c, d
Orvik, K. A. and Skagseth, Ø.: Monitoring the Norwegian Atlantic slope current using a single moored current meter, Cont. Shelf Res., 23, 159–176, https://doi.org/10.1016/S0278-4343(02)00172-3, 2003a. a, b
Orvik, K. A. and Skagseth, Ø.: The impact of the wind stress curl in the North Atlantic on the Atlantic inflow to the Norwegian Sea toward the Arctic, Geophys. Res. Lett., 30, 1884, https://doi.org/10.1029/2003GL017932, 2003b. a
Østerhus, S., Woodgate, R., Valdimarsson, H., Turrell, B., de Steur, L., Quadfasel, D., Olsen, S. M., Moritz, M., Lee, C. M., Larsen, K. M. H., Jónsson, S., Johnson, C., Jochumsen, K., Hansen, B., Curry, B., Cunningham, S., and Berx, B.: Arctic Mediterranean exchanges: a consistent volume budget and trends in transports from two decades of observations, Ocean Sci., 15, 379–399, https://doi.org/10.5194/os-15-379-2019, 2019 (data available at: http://www.oceansites.org/tma/gsr.html, last access: 9 April 2024). a, b, c, d, e, f, g, h
Palter, J. B.: The Role of the Gulf Stream in European Climate, Annu. Rev. Mar. Sci., 7, 113–137, https://doi.org/10.1146/annurev-marine-010814-015656, 2015. a
Piecuch, C. G.: Likely weakening of the Florida Current during the past century revealed by sea-level observations, Nat. Commun., 11, 3973, https://doi.org/10.1038/s41467-020-17761-w, 2020. a
Piecuch, C. G. and Beal, L. M.: Robust Weakening of the Gulf Stream During the Past Four Decades Observed in the Florida Straits, Geophys. Res. Lett., 50, e2023GL105170, https://doi.org/10.1029/2023GL105170, 2023. a
Piecuch, C. G., Ponte, R. M., Little, C. M., Buckley, M. W., and Fukumori, I.: Mechanisms underlying recent decadal changes in subpolar North Atlantic Ocean heat content, J. Geophys. Res.-Oceans, 122, 7181–7197, https://doi.org/10.1002/2017JC012845, 2017. a, b
Polyakov, I. V., Ingvaldsen, R. B., Pnyushkov, A. V., Bhatt, U. S., Francis, J. A., Janout, M., Kwok, R., and Skagseth, Ø.: Fluctuating Atlantic inflows modulate Arctic atlantification, Science, 381, 972–979, https://doi.org/10.1126/science.adh5158, 2023. a
Rhein, M., Mertens, C., and Roessler, A.: Observed Transport Decline at 47°N, Western Atlantic, J. Geophys. Res.-Oceans, 124, 4875–4890, https://doi.org/10.1029/2019JC014993, 2019. a
Richter, K., Furevik, T., and Orvik, K. A.: Effect of wintertime low-pressure systems on the Atlantic inflow to the Nordic seas, J. Geophys. Res., 114, C09006, https://doi.org/10.1029/2009JC005392, 2009. a
Roberts, C. D., Waters, J., Peterson, K. A., Palmer, M. D., McCarthy, G. D., Frajka‐Williams, E., Haines, K., Lea, D. J., Martin, M. J., Storkey, D., Blockley, E. W., and Zuo, H.: Atmosphere drives recent 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. a, b
Roessler, A., Rhein, M., Kieke, D., and Mertens, C.: Long-term observations of North Atlantic Current transport at the gateway between western and eastern Atlantic, J. Geophys. Res.-Oceans, 120, 4003–4027, https://doi.org/10.1002/2014JC010662, 2015. a
Roquet, F. and Wunsch, C.: The Atlantic Meridional Overturning Circulation and its Hypothetical Collapse, Tellus A, 74, 393–398, https://doi.org/10.16993/tellusa.679, 2022. a
Rossby, T., Flagg, C. N., and Donohue, K.: Interannual variations in upper-ocean transport by the Gulf Stream and adjacent waters between New Jersey and Bermuda, J. Marine Res., 63, 203–226, 2005. a
Rossby, T., Flagg, C. N., Donohue, K., Sanchez-Franks, A., and Lillibridge, J.: On the long-term stability of Gulf Stream transport based on 20 years of direct measurements, Geophys. Res. Lett., 41, 114–120, https://doi.org/10.1002/2013GL058636, 2014. a, b
Rossby, T., Flagg, C., Dohan, K., Fontana, S., Curry, R., Andres, M., and Forsyth, J.: Oleander is More than a Flower: Twenty-Five Years of Oceanography Aboard a Merchant Vessel, Oceanography, 32, 126–137, https://doi.org/10.5670/oceanog.2019.319, 2019 (data available at: https://oleander.bios.asu.edu/data/oleander-fluxes/, last access: 4 June 2024). a, b, c
Rossby, T., Chafik, L., and Houpert, L.: What can Hydrography Tell Us about the strength of the Nordic Seas MOC over the last 70 to 100 years?, Geophys. Res. Lett., 47, e2020GL087456, https://doi.org/10.1029/2020GL087456, 2020. a, b
Sanchez-Franks, A., Hameed, S., and Wilson, R. E.: The Icelandic Low as a Predictor of the Gulf Stream North Wall Position, J. Phys. Oceanogr., 46, 817–826, https://doi.org/10.1175/JPO-D-14-0244.1, 2016. a
Sanders, R. N. C., Jones, D. C., Josey, S. A., Sinha, B., and Forget, G.: Causes of the 2015 North Atlantic cold anomaly in a global state estimate, Ocean Sci., 18, 953–978, https://doi.org/10.5194/os-18-953-2022, 2022. a
Sarafanov, A.: On the effect of the North Atlantic Oscillation on temperature and salinity of the subpolar North Atlantic intermediate and deep waters, ICES J. Marine Sci., 66, 1448–1454, https://doi.org/10.1093/icesjms/fsp094, 2009. a, b
Sen Gupta, A., Stellema, A., Pontes, G. M., Taschetto, A. S., Vergés, A., and Rossi, V.: Future changes to the upper ocean Western Boundary Currents across two generations of climate models, Sci. Rep., 11, 9538, https://doi.org/10.1038/s41598-021-88934-w, 2021. a, b, c
Skagseth, Ø. and Orvik, K. A.: Identifying fluctuations in the Norwegian Atlantic Slope Current by means of empirical orthogonal functions, Cont. Shelf Res., 22, 547–563, https://doi.org/10.1016/S0278-4343(01)00086-3, 2002. a
Smeed, D. A., Josey, S. A., Beaulieu, C., Johns, W. E., Moat, B. I., Frajka-Williams, E., Rayner, D., Meinen, C. S., Baringer, M. O., Bryden, H. L., and McCarthy, G. D.: The North Atlantic Ocean Is in a State of Reduced Overturning, Geophys. Res. Lett., 45, 1527–1533, https://doi.org/10.1002/2017GL076350, 2018. a, b, c
Tesdal, J. and Haine, T. W. N.: Dominant terms in the freshwater and heat budgets of the subpolar North Atlantic Ocean and Nordic Seas from 1992 to 2015, J. Geophys. Res.-Oceans, 125, e2020JC016435, https://doi.org/10.1029/2020JC016435, 2020. a
Thornalley, D. J. R., Oppo, D. W., Ortega, P., Robson, J. I., Brierley, C. M., Davis, R., Hall, I. R., Moffa-Sanchez, P., Rose, N. L., Spooner, P. T., Yashayaev, I., and Keigwin, L. D.: Anomalously weak Labrador Sea convection and Atlantic overturning during the past 150 years, Nature, 556, 227–230, https://doi.org/10.1038/s41586-018-0007-4, 2018. a
Weijer, W., Cheng, W., Garuba, O. A., Hu, A., and Nadiga, B. T.: CMIP6 Models Predict Significant 21st Century Decline of the Atlantic Meridional Overturning Circulation, Geophys. Res. Lett., 47, e2019GL086075, https://doi.org/10.1029/2019GL086075, 2020. a, b, c
Worthington, E. L., Moat, B. I., Smeed, D. A., Mecking, J. V., Marsh, R., and McCarthy, G. D.: A 30-year reconstruction of the Atlantic meridional overturning circulation shows no decline, Ocean Sci., 17, 285–299, https://doi.org/10.5194/os-17-285-2021, 2021. a
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. a
Zhang, R.: Latitudinal dependence of Atlantic meridional overturning circulation (AMOC) variations, Geophys. Res. Lett., 37, L16703, https://doi.org/10.1029/2010GL044474, 2010. a
Zhang, R., Sutton, R., Danabasoglu, G., Kwon, Y. O., Marsh, R., Yeager, S. G., Amrhein, D. E., and Little, C. M.: A Review of the Role of the Atlantic Meridional Overturning Circulation in Atlantic Multidecadal Variability and Associated Climate Impacts, Rev. Geophys., 57, 316–375, https://doi.org/10.1029/2019RG000644, 2019. a
Zhao, J. and Johns, W.: Wind-forced interannual variability of the Atlantic Meridional Overturning Circulation at 26.5°N, J. Geophys. Res.-Oceans, 119, 2403–2419, https://doi.org/10.1002/2013JC009407, 2014. a, b, c
Zou, S., Lozier, M. S., and Xu, X.: Latitudinal Structure of the Meridional Overturning Circulation Variability on Interannual to Decadal Time Scales in the North Atlantic Ocean, J. Climate, 33, 3845–3862, https://doi.org/10.1175/JCLI-D-19-0215.1, 2020. a
Short summary
The Gulf Stream system is essential for northward ocean heat transport. Here, we use observations along the path of the extended Gulf Stream system and an observationally constrained ocean model to investigate variability in the Gulf Stream system since the 1990s. We find regional differences in the variability between the subtropical, subpolar, and Nordic Seas regions, which warrants caution in using observational records at a single latitude to infer large-scale circulation change.
The Gulf Stream system is essential for northward ocean heat transport. Here, we use...
