Articles | Volume 17, issue 5
https://doi.org/10.5194/os-17-1177-2021
© Author(s) 2021. 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-17-1177-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
02 Sep 2021
Research article |
| 02 Sep 2021
| 02 Sep 2021
Regional imprints of changes in the Atlantic Meridional Overturning Circulation in the eddy-rich ocean model VIKING20X
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Christian-Albrechts Universität zu Kiel, Kiel, Germany
Franziska U. Schwarzkopf
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Klaus Getzlaff
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Siren Rühs
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Torge Martin
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Markus Scheinert
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Tobias Schulzki
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Patricia Handmann
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Rebecca Hummels
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Claus W. Böning
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Christian-Albrechts Universität zu Kiel, Kiel, Germany
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Patrick Wagner and Claus W. Böning
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Short summary
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Katja Matthes, Arne Biastoch, Sebastian Wahl, Jan Harlaß, Torge Martin, Tim Brücher, Annika Drews, Dana Ehlert, Klaus Getzlaff, Fritz Krüger, Willi Rath, Markus Scheinert, Franziska U. Schwarzkopf, Tobias Bayr, Hauke Schmidt, and Wonsun Park
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A family of nested global ocean general circulation model configurations, the INALT family, has been established with resolutions of 1/10°, 1/20° and 1/60° in the South Atlantic and western Indian oceans, covering the greater Agulhas Current (AC) system. The INALT family provides a consistent set of configurations that allows to address eddy dynamics in the AC system and their impact on the large-scale ocean circulation.
Josefine Maas, Susann Tegtmeier, Birgit Quack, Arne Biastoch, Jonathan V. Durgadoo, Siren Rühs, Stephan Gollasch, and Matej David
Ocean Sci., 15, 891–904, https://doi.org/10.5194/os-15-891-2019, https://doi.org/10.5194/os-15-891-2019, 2019
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In a large-scale analysis, the spread of disinfection by-products from oxidative ballast water treatment is investigated, with a focus on Southeast Asia where major ports are located. Halogenated compounds such as bromoform (CHBr3) are produced in the ballast water and, once emitted into the environment, can participate in ozone depletion. Anthropogenic bromoform is rapidly emitted into the atmosphere and can locally double around large ports. A large-scale impact cannot be found.
Siren Rühs, Franziska U. Schwarzkopf, Sabrina Speich, and Arne Biastoch
Ocean Sci., 15, 489–512, https://doi.org/10.5194/os-15-489-2019, https://doi.org/10.5194/os-15-489-2019, 2019
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We revisit the sources for the upper limb of the overturning circulation in the South Atlantic by tracking fluid particles in a high-resolution ocean model. Our results suggest that the upper limb’s transport is dominantly supplied by waters with Indian Ocean origin, but the contribution of waters with Pacific origin is substantially larger than previously estimated with coarse-resolution models. Yet, a large part of upper limb waters obtains thermohaline properties within the South Atlantic.
Olaf Duteil, Andreas Oschlies, and Claus W. Böning
Biogeosciences, 15, 7111–7126, https://doi.org/10.5194/bg-15-7111-2018, https://doi.org/10.5194/bg-15-7111-2018, 2018
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Oxygen-depleted regions of the Pacific Ocean are currently expanding, which is threatening marine habitats. Based on numerical simulations, we show that the decrease in the intensity of the trade winds and the subsequent slowdown of the oceanic currents lead to a reduction in oxygen supply. Our study suggests that the prevailing positive conditions of the Pacific Decadal Oscillation since 1975, a major source of natural variability, may explain a significant part of the current deoxygenation.
Rafael Abel, Claus W. Böning, Richard J. Greatbatch, Helene T. Hewitt, and Malcolm J. Roberts
Ocean Sci. Discuss., https://doi.org/10.5194/os-2017-24, https://doi.org/10.5194/os-2017-24, 2017
Revised manuscript not accepted
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In coupled global atmosphere ocean models a feedback from ocean surface currents to atmospheric winds was found. Surface winds are energized by about 30 % of the ocean currents. We were able to implement this feedback in uncoupled ocean models which results in a realistic surface flux coupling. Due to changes in the dissipation the kinetic energy of the time-variable flow is increased up to 10 % when this feedback is implemented. Implementation in other models should be straightforward.
Stephen M. Griffies, Gokhan Danabasoglu, Paul J. Durack, Alistair J. Adcroft, V. Balaji, Claus W. Böning, Eric P. Chassignet, Enrique Curchitser, Julie Deshayes, Helge Drange, Baylor Fox-Kemper, Peter J. Gleckler, Jonathan M. Gregory, Helmuth Haak, Robert W. Hallberg, Patrick Heimbach, Helene T. Hewitt, David M. Holland, Tatiana Ilyina, Johann H. Jungclaus, Yoshiki Komuro, John P. Krasting, William G. Large, Simon J. Marsland, Simona Masina, Trevor J. McDougall, A. J. George Nurser, James C. Orr, Anna Pirani, Fangli Qiao, Ronald J. Stouffer, Karl E. Taylor, Anne Marie Treguier, Hiroyuki Tsujino, Petteri Uotila, Maria Valdivieso, Qiang Wang, Michael Winton, and Stephen G. Yeager
Geosci. Model Dev., 9, 3231–3296, https://doi.org/10.5194/gmd-9-3231-2016, https://doi.org/10.5194/gmd-9-3231-2016, 2016
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The Ocean Model Intercomparison Project (OMIP) aims to provide a framework for evaluating, understanding, and improving the ocean and sea-ice components of global climate and earth system models contributing to the Coupled Model Intercomparison Project Phase 6 (CMIP6). This document defines OMIP and details a protocol both for simulating global ocean/sea-ice models and for analysing their output.
H. Dietze, U. Löptien, and K. Getzlaff
Geosci. Model Dev., 7, 1713–1731, https://doi.org/10.5194/gmd-7-1713-2014, https://doi.org/10.5194/gmd-7-1713-2014, 2014
D. Le Bars, J. V. Durgadoo, H. A. Dijkstra, A. Biastoch, and W. P. M. De Ruijter
Ocean Sci., 10, 601–609, https://doi.org/10.5194/os-10-601-2014, https://doi.org/10.5194/os-10-601-2014, 2014
Related subject area
Approach: Numerical Models | Properties and processes: Overturning circulation | Depth range: All Depths | Geographical range: Deep Seas: North Atlantic | Challenges: Oceans and climate
Seasonal overturning variability in the eastern North Atlantic subpolar gyre: a Lagrangian perspective
On the ocean's response to enhanced Greenland runoff in model experiments: relevance of mesoscale dynamics and atmospheric coupling
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.
Torge Martin and Arne Biastoch
Ocean Sci., 19, 141–167, https://doi.org/10.5194/os-19-141-2023, https://doi.org/10.5194/os-19-141-2023, 2023
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How is the ocean affected by continued Greenland Ice Sheet mass loss? We show in a systematic set of model experiments that atmospheric feedback needs to be accounted for as the large-scale ocean circulation is more than twice as sensitive to the meltwater otherwise. Coastal winds, boundary currents, and ocean eddies play a key role in redistributing the meltwater. Eddy paramterization helps the coarse simulation to perform better in the Labrador Sea but not in the North Atlantic Current region.
Cited articles
Aksamit, N. O., Sapsis, T., and Haller, G.: Machine-Learning Mesoscale and
Submesoscale Surface Dynamics from Lagrangian Ocean Drifter Trajectories, J.
Phys. Oceanogr., 50, 1179–1196, https://doi.org/10.1175/JPO-D-19-0238.1, 2020. a
Amante, C. and Eakins, B.: ETOPO1 1 Arc-Minute Global Relief Model:
Procedures, Data Sources and Analysis, NOAA Tech. Memo. NESDIS NGDC-24,
p. 19, https://doi.org/10.1594/PANGAEA.769615, 2009. a
Arakawa, A. and Hsu, Y.-J. G.: Energy Conserving and Potential-Enstrophy
Dissipating Schemes for the Shallow Water Equations, Mon. Weather Rev., 118, 1960–1969,
1990. a
Baltazar-Soares, M., Biastoch, A., Harrod, C., Hanel, R., Marohn, L., Prigge,
E., Evans, D., Bodles, K., Behrens, E., Böning, C. W., and Eizaguirre,
C.: Recruitment collapse and population structure of the european eel shaped
by local ocean current dynamics, Curr. Biol., 24, 104–108,
https://doi.org/10.1016/j.cub.2013.11.031, 2014. a
Bamber, J. L., Tedstone, A. J., King, M. D., Howat, I. M., Enderlin, E. M.,
van den Broeke, M. R., and Noel, B.: Land Ice Freshwater Budget of the
Arctic and North Atlantic Oceans: 1. Data, Methods, and Results, J. Geophys.
Res.-Ocean., 123, 1827–1837, https://doi.org/10.1002/2017JC013605, 2018. a
Barnier, B., Madec, G., Penduff, T., Molines, J.-M., Treguier, A.-M.,
Le Sommer, J., Beckmann, A., Biastoch, A., Böning, C., Dengg, J., Derval,
C., Durand, E., Gulev, S., Remy, E., Talandier, C., Theetten, S., Maltrud,
M., McClean, J., and De Cuevas, B.: Impact of partial steps and momentum
advection schemes in a global ocean circulation model at eddy-permitting
resolution, Ocean Dynam., 56, 543–567, 2006. a, b, c
Behrens, E., Biastoch, A., and Böning, C. W.: Spurious AMOC trends in
global ocean sea-ice models related to subarctic freshwater forcing, Ocean
Model., 69, 39–49, https://doi.org/10.1016/j.ocemod.2013.05.004, 2013. a, b, c, d
Behrens, E., Våge, K., Harden, B., Biastoch, A., and Böning, C. W.:
Composition and variability of the Denmark Strait Overflow Water in a
high-resolution numerical model hindcast simulation, J. Geophys. Res.-Ocean., 122, 2830–2846, https://doi.org/10.1002/2016JC012158, 2017. 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
Biastoch, A., Böning, C. W., Getzlaff, J., Molines, J.-M., and Madec, G.:
Causes of interannual-decadal variability in the meridional overturning
circulation of the mid-latitude North Atlantic Ocean, J. Clim., 21,
6599–6615, https://doi.org/10.1175/2008JCLI2404.1, 2008a. a, b, c, d
Biastoch, A., Böning, C. W., and Lutjeharms, J. R.: Agulhas leakage
dynamics affects decadal variability in Atlantic overturning circulation,
Nature, 456, 489–492, https://doi.org/10.1038/nature07426, 2008b. a
Biastoch, A., Böning, C. W., Schwarzkopf, F. U., and Lutjeharms, J.
R. E.: Increase in Agulhas leakage due to poleward shift of Southern
Hemisphere westerlies, Nature, 462, 495–498, https://doi.org/10.1038/nature08519,
2009. a
Biastoch, A, Schwarzkopf, F. U., Getzlaff, K., Rühs, S., Martin, T., Scheinert, M., Schulzki, T., Handmann, P., Hummels, R., and Claus W. Böning: Supplementary Data to Biastoch et al. (2021): Regional Imprints of Changes in the Atlantic Meridional Overturning Circulation in the Eddy-rich Ocean Model VIKING20X [data set], available at: https://hdl.handle.net/20.500.12085/a8f98a1a-473f-11ea-a036-c81f66eb46c3 (last access: 26 August 2021), 2021. a
Biló, T. C. and Johns, W. E.: Interior Pathways of Labrador Sea Water in
the North Atlantic From the Argo Perspective, Geophys. Res. Lett., 46,
3340–3348, https://doi.org/10.1029/2018GL081439, 2019. 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, 23, https://doi.org/10.1029/2007GL031731, 2007. a
Blanke, B. and Delecluse, P.: Variability of the Tropical Atlantic Ocean
Simulated by a General Circulation Model with Two Different Mixed-Layer
Physics, J. Phys. Oceanogr., 23, 1363–1388, 1993. a
Blindheim, J. and Osterhus, S.: The Nordic Seas, main oceanographic features, in :The Nordic Seas: An Integrated Perspective, Vol. 158,
Geophysical Monograph Series, 158, 11–37, 2005. a
Böning, C. W., Scheinert, M., Dengg, J., Biastoch, A., and Funk, A.:
Decadal variability of subpolar gyre transport and its reverberation in the
North Atlantic overturning, Geophys. Res. Lett., 33, 21,
https://doi.org/10.1029/2006GL026906, 2006. a, b, c
Böning, C. W., Behrens, E., Biastoch, A., Getzlaff, K., and Bamber,
J. L.: Emerging impact of Greenland meltwater on deepwater formation in the
North Atlantic Ocean, Nat. Geosci., 9, 523–527, https://doi.org/10.1038/ngeo2740,
2016. a, b, c, d
Bourdallé-Badie, R. and Treguier, A.: A climatology of runoff for the
global ocean-ice model ORCA025, Mercator-Ocean reference M0O-RP-425-365-MER,
2006. a
Bower, A., Lozier, S., Biastoch, A., Drouin, K., Foukal, N., Furey, H.,
Lankhorst, M., Rühs, S., and Zou, S.: Lagrangian Views of the Pathways
of the Atlantic Meridional Overturning Circulation, J. Geophys. Res.-Ocean.,
124, 5313–5335, https://doi.org/10.1029/2019JC015014, 2019. a
Bower, A. S., Lozier, M. S., Gary, S. F., and Böning, C. W.: Interior
pathways of the North Atlantic meridional overturning circulation., Nature,
459, 243–247, https://doi.org/10.1038/nature07979, 2009. a
Brandt, P., Schott, F. A., Funk, A., and Martins, C. S.: Seasonal to
interannual variability of the eddy field in the Labrador Sea from satellite
altimetry, J. Geophys. Res., 109, C02028, https://doi.org/10.1029/2002JC001551, 2004. a
Breckenfelder, T., Rhein, M., Roessler, A., Böning, C. W., Biastoch, A.,
Behrens, E., and Mertens, C.: Flow paths and variability of the North
Atlantic Current: A comparison of observations and a high-resolution model,
J. Geophys. Res.-Ocean., 122, 2686–2708, https://doi.org/10.1002/2016JC012444, 2017. a, b, c
Breusing, C., Biastoch, A., Drews, A., Metaxas, A., Jollivet, D., Vrijenhoek,
R. C., Bayer, T., Melzner, F., Sayavedra, L., Petersen, J. M., Dubilier, N.,
Schilhabel, M. B., Rosenstiel, P., and Reusch, T. B. H.: Biophysical and
Population Genetic Models Predict the Presence of “Phantom” Stepping
Stones Connecting Mid-Atlantic Ridge Vent Ecosystems, Curr. Biol., 26,
2257–2267, https://doi.org/10.1016/j.cub.2016.06.062, 2016. a
Brodeau, L., Barnier, B., Treguier, A. M., Penduff, T., and Gulev, S.: An
ERA40-based atmospheric forcing for global ocean circulation models, Ocean
Model., 31, 88–104, https://doi.org/10.1016/j.ocemod.2009.10.005, 2010. a
Buckley, M. W. and Marshall, J.: Observations, inferences, and mechanisms of
the Atlantic Meridional Overturning Circulation: A review, Rev. Geophys.,
54, 5–63, https://doi.org/10.1002/2015RG000493, 2016. 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
Chanut, J., Barnier, B., Large, W., Debreu, L., Penduff, T., Molines, J. M.,
and Mathiot, P.: Mesoscale eddies in the Labrador Sea and their contribution
to convection and restratification, J. Phys. Oceanogr., 38, 1617–1643,
https://doi.org/10.1175/2008JPO3485.1, 2008. a
Chassignet, E. P. and Xu, X.: Impact of horizontal resolution (
Colombo, P., Barnier, B., Penduff, T., Chanut, J., Deshayes, J., Molines,
J. M., Le Sommer, J., Verezemskaya, P., Gulev, S., and Treguier, A. M.:
Representation of the Denmark Strait overflow in a z-coordinate eddying
configuration of the NEMO (v3.6) ocean model: Resolution and parameter
impacts, Geosci. Model Dev., 13, 3347–3371, https://doi.org/10.5194/gmd-13-3347-2020,
2020. a
Danabasoglu, G., Yeager, S. G., Bailey, D., Behrens, E., Bentsen, M., Bi, D.,
Biastoch, A., Böning, C., Bozec, A., Canuto, V. M., Cassou, C.,
Chassignet, E., Coward, A. C., Danilov, S., Diansky, N., Drange, H., Farneti,
R., Fernandez, E., Fogli, P. G., Forget, G., Fujii, Y., Griffies, S. M.,
Gusev, A., Heimbach, P., Howard, A., Jung, T., Kelley, M., Large, W. G.,
Leboissetier, A., Lu, J., Madec, G., Marsland, S. J., Masina, S., Navarra,
A., George Nurser, A. J., Pirani, A., y Mélia, D. S., Samuels, B. L.,
Scheinert, M., Sidorenko, D., Treguier, A. M., Tsujino, H., Uotila, P.,
Valcke, S., Voldoire, A., and Wang, Q.: North Atlantic simulations in
Coordinated Ocean-ice Reference Experiments phase II (CORE-II), Part I: Mean
states, Ocean Model., 73, 76–107, https://doi.org/10.1016/j.ocemod.2013.10.005, 2014. a, b, c
Danabasoglu, G., Yeager, S. G., Kim, W. M., Behrens, E., Bentsen, M., Bi, D.,
Biastoch, A., Bleck, R., Böning, C., Bozec, A., Canuto, V. M., Cassou,
C., Chassignet, E., Coward, A. C., Danilov, S., Diansky, N., Drange, H.,
Farneti, R., Fernandez, E., Fogli, P. G., Forget, G., Fujii, Y., Griffies,
S. M., Gusev, A., Heimbach, P., Howard, A., Ilicak, M., Jung, T., Karspeck,
A. R., Kelley, M., Large, W. G., Leboissetier, A., Lu, J., Madec, G.,
Marsland, S. J., Masina, S., Navarra, A., Nurser, A. J., Pirani, A., Romanou,
A., Mélia David, S., Samuels, B. L., Scheinert, M., Sidorenko, D.,
Sun, S., Treguier, A. M., Tsujino, H., Uotila, P., Valcke, S., Voldoire, A.,
Wang, Q., and Yashayaev, I.: North Atlantic simulations in Coordinated
Ocean-ice Reference Experiments phase II (CORE-II). Part II: Inter-annual to
decadal variability, Ocean Model., 97, 65–90,
https://doi.org/10.1016/j.ocemod.2015.11.007, 2016. a, b
Debreu, L., Vouland, C., and Blayo, E.: AGRIF: Adaptive grid refinement in
Fortran, Comput. Geosci., 34, 8–13,
https://doi.org/10.1016/j.cageo.2007.01.009, 2008. a
Dengler, M., Schott, F. A., Eden, C., Brandt, P., Fischer, J., and Zantopp,
R. J.: Break-up of the Atlantic deep western boundary current into eddies at
8∘ S, Nature, 432, 1018–1020, https://doi.org/10.1038/nature03134, 2004. a, b
Dickson, R. R. and Brown, J.: The production of North Atlantic Deep Water:
sources, rates, and pathways, J. Geophys. Res., 99, 12319–12341,
https://doi.org/10.1029/94jc00530, 1994. a
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,
https://doi.org/10.1175/2008JPO4001.1, 2009. a
Eden, C. and Böning, C.: Sources of eddy kinetic energy in the Labrador
Sea, J. Phys. Oceanogr., 32, 3346–3363,
https://doi.org/10.1175/1520-0485(2002)032<3346:SOEKEI>2.0.CO;2, 2002. a
Eyring, V., Bony, S., Meehl, G. A., Senior, C. A., Stevens, B., Stouffer,
R. J., and Taylor, K. E.: Overview of the Coupled Model Intercomparison
Project Phase 6 (CMIP6) experimental design and organization, Geosci. Model
Dev., 9, 1937–1958, https://doi.org/10.5194/gmd-9-1937-2016, 2016. a
Fichefet, T. and Morales Maqueda, M. A.: Sensitivity of a global sea ice
model to the treatment of ice thermodynamic and dynamics, J. Geophys. Res.,
102, 12609–12646, https://doi.org/10.1029/97JC00480, 1997. a
Fischer, J., Schott, F. A., and Dengler, M.: Boundary circulation at the exit
of the Labrador Sea, J. Phys. Oceanogr., 34, 1548–1570,
https://doi.org/10.1175/1520-0485(2004)034<1548:BCATEO>2.0.CO;2, 2004. a, b, c
Fischer, J., Karstensen, J., Zantopp, R., Visbeck, M., Biastoch, A., Behrens,
E., Böning, C. W., Quadfasel, D., Jochumsen, K., Valdimarsson, H.,
Jónsson, S., Bacon, S., Holliday, N. P., Dye, S., Rhein, M., and
Mertens, C.: Intra-seasonal variability of the DWBC in the western subpolar
North Atlantic, Prog. Oceanogr., 132, 233–249,
https://doi.org/10.1016/j.pocean.2014.04.002, 2015. a
Fox-Kemper, B., Adcroft, A., Böning, C. W., Chassignet, E. P.,
Curchitser, E., Danabasoglu, G., Eden, C., England, M. H., Gerdes, R.,
Greatbatch, R. J., Griffies, S. M., Hallberg, R. W., Hanert, E., Heimbach,
P., Hewitt, H. T., Hill, C. N., Komuro, Y., Legg, S., Sommer, J. L., Masina,
S., Marsland, S. J., Penny, S. G., Qiao, F., Ringler, T. D., Treguier, A. M.,
Tsujino, H., Uotila, P., and Yeager, S. G.: Challenges and prospects in
ocean circulation models, Front. Mar. Sci., 6, 65, https://doi.org/10.3389/fmars.2019.00065, 2019. 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, b
Gary, S. F., Lozier, M., Böning, C. W., and Biastoch, A.: Deciphering
the pathways for the deep limb of the Meridional Overturning Circulation,
Deep-Sea Res. Pt. II, 58, 1781–1797,
https://doi.org/10.1016/j.dsr2.2010.10.059, 2011. a
Gary, S. F., Fox, A. D., Biastoch, A., Roberts, J. M., and Cunningham, S. A.:
Larval behaviour, dispersal and population connectivity in the deep sea,
Sci. Rep., 10, 10675, https://doi.org/10.1038/s41598-020-67503-7, 2020. a
Garzoli, S. L. and Matano, R.: The South Atlantic and the Atlantic Meridional
Overturning Circulation, Deep-Sea Res. Pt. II, 58,
1837–1847, https://doi.org/10.1016/j.dsr2.2010.10.063, 2011. a
Getzlaff, K., Böning, C. W., and Dengg, J.: Lagrangian perspectives of
deep water export from the subpolar North Atlantic, Geophys. Res. Lett., 33, 21,
https://doi.org/10.1029/2006GL026470, 2006. a
Griffies, S. M., Biastoch, A., Böning, C., Bryan, F., Danabasoglu, G.,
Chassignet, E. P., England, M. H., Gerdes, R., Haak, H., Hallberg, R. W.,
Hazeleger, W., Jungclaus, J., Large, W. G., Madec, G., Pirani, A., Samuels,
B. L., Scheinert, M., Gupta, A. S., Severijns, C. a., Simmons, H. L.,
Treguier, A. M., Winton, M., Yeager, S., and Yin, J.: Coordinated Ocean-ice
Reference Experiments (COREs), Ocean Model., 26, 1–46,
https://doi.org/10.1016/j.ocemod.2008.08.007, 2009. a, b, c, d, e, f
Griffies, S. M., Danabasoglu, G., Durack, P. J., Adcroft, A. J., Balaji, V.,
Böning, C. W., Chassignet, E. P., Curchitser, E., Deshayes, J., Drange,
H., Fox-Kemper, B., Gleckler, P. J., Gregory, J. M., Haak, H., Hallberg,
R. W., Heimbach, P., Hewitt, H. T., Holland, D. M., Ilyina, T., Jungclaus,
J. H., Komuro, Y., Krasting, J. P., Large, W. G., Marsland, S. J., Masina,
S., McDougall, T. J., George Nurser, A. J., Orr, J. C., Pirani, A., Qiao,
F., Stouffer, R. J., Taylor, K. E., Treguier, A. M., Tsujino, H., Uotila, P.,
Valdivieso, M., Wang, Q., Winton, M., and Yeager, S. G.: OMIP contribution
to CMIP6: Experimental and diagnostic protocol for the physical component of
the Ocean Model Intercomparison Project, Geosci. Model Dev., 9, 3231–3296,
https://doi.org/10.5194/gmd-9-3231-2016, 2016. a, b
Hallberg, R.: Using a resolution function to regulate parameterizations of
oceanic mesoscale eddy effects, Ocean Model., 72, 92–103,
2013. a
Handmann, P., Fischer, J., Visbeck, M., Karstensen, J., Biastoch, A.,
Böning, C., and Patara, L.: The Deep Western Boundary Current in the
Labrador Sea From Observations and a High-Resolution Model, J. Geophys. Res.-Ocean., 123, 2829–2850, https://doi.org/10.1002/2017JC013702, 2018. a, b, c, d, e, f, g
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, b
Harden, B. E., Pickart, R. S., Valdimarsson, H., Våge, K., de Steur, L.,
Richards, C., Bahr, F., Torres, D., Børve, E., Jónsson, S.,
Macrander, A., Østerhus, S., Håvik, L., and Hattermann, T.: Upstream
sources of the Denmark Strait Overflow: Observations from a high-resolution
mooring array, Deep-Sea Res. Pt. I, 112, 94–112,
https://doi.org/10.1016/j.dsr.2016.02.007, 2016. a, b
Herrford, J., Brandt, P., Kanzow, T., Hummels, R., Araujo, M., and Durgadoo,
J. V.: Seasonal variability of the Atlantic Meridional Overturning
Circulation at 11∘ S inferred from bottom pressure measurements,
Ocean Sci., 17, 265–284, https://doi.org/10.5194/os-17-265-2021, 2021. a, b, c
Hewitt, H. T., Roberts, M., Mathiot, P., Biastoch, A., Blockley, E.,
Chassignet, E. P., Fox-Kemper, B., Hyder, P., Marshall, D. P., Popova, E.,
Treguier, A. M., Zanna, L., Yool, A., Yu, Y., Beadling, R., Bell, M.,
Kuhlbrodt, T., Arsouze, T., Bellucci, A., Castruccio, F., Gan, B.,
Putrasahan, D., Roberts, C. D., Van Roekel, L., and Zhang, Q.: Resolving
and Parameterising the Ocean Mesoscale in Earth System Models, Curr. Clim.
Chang. Report., 6, 137–152, https://doi.org/10.1007/s40641-020-00164-w, 2020. a, b
Hirschi, J. J., 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, b
Hirschi, J. J., Barnier, B., Böning, C., Biastoch, A., Blaker, A. T.,
Coward, A., Danilov, S., Drijfhout, S., Getzlaff, K., Griffies, S. M.,
Hasumi, H., Hewitt, H., Iovino, D., Kawasaki, T., Kiss, A. E., Koldunov, N.,
Marzocchi, A., Mecking, J. V., Moat, B., Molines, J. M., Myers, P. G.,
Penduff, T., Roberts, M., Treguier, A. M., Sein, D. V., Sidorenko, D., Small,
J., Spence, P., Thompson, L. A., Weijer, W., and Xu, X.: The Atlantic
Meridional Overturning Circulation in High-Resolution Models, J. Geophys.
Res.-Ocean., 125, e2019JC015522, https://doi.org/10.1029/2019JC015522, 2020. a, b, c, d
Hollingsworth, A., Kållberg, P., Renner, V., and Burridge, D. M.: An
internal symmetric computational instability, Q. J. Roy.
Meteor. Soc., 109, 417–428, 1983. a
Hummels, R., Brandt, P., Dengler, M., Fischer, J., Araujo, M., Veleda, D., and
Durgadoo, J. V.: Interannual to decadal changes in the western boundary
circulation in the Atlantic at 11∘ S, Geophys. Res. Lett., 42, 7615–7622,
https://doi.org/10.1002/2015GL065254, 2015. a, b, c, d
Jackson, L. C., Dubois, C., Forget, G., Haines, K., Harrison, M., Iovino, D.,
Köhl, A., Mignac, D., Masina, S., Peterson, K. A., Piecuch, C. G.,
Roberts, C. D., Robson, J., Storto, A., Toyoda, T., Valdivieso, M., Wilson,
C., Wang, Y., and Zuo, H.: The Mean State and Variability of the North
Atlantic Circulation: A Perspective From Ocean Reanalyses, J.
Geophys. Res.-Ocean., 124, 9141–9170,
https://doi.org/10.1029/2019JC015210, 2019. a
Jochumsen, K., Moritz, M., Nunes, N., Quadfasel, D., Larsen, K. M. H., Hansen,
B., Valdimarsson, H., and Jonsson, S.: Revised transport estimates of the
Denmark Strait overflow, J. Geophys. Res.-Ocean., 122, 3434–3450,
https://doi.org/10.1002/2017JC012803, 2017. a
Karspeck, A. R., Stammer, D., Köhl, A., Danabasoglu, G., Balmaseda, M.,
Smith, D. M., Fujii, Y., Zhang, S., Giese, B., Tsujino, H., and Rosati, A.:
Comparison of the Atlantic meridional overturning circulation between 1960
and 2007 in six ocean reanalysis products, Clim. Dynam., 49, 957–982,
https://doi.org/10.1007/s00382-015-2787-7, 2015. a
Käse, R. H., Girton, J. B., and Sanford, T. B.: Structure and
variability of the Denmark Strait Overflow: Model and observations, J.
Geophys. Res.-Ocean., 108, 3181, https://doi.org/10.1029/2002jc001548, 2003. a
Kersalé, M., Meinen, C. S., Perez, R. C., Piola, A. R., Speich, S., Campos, E. J. D., Garzoli, S. L., Ansorge, I., Volkov, D. L., Le Hénaff, M., Dong, S., Lamont, T., Sato, O. T., and van den Berg, M.: Multi-year estimates of daily heat transport by the Atlantic meridional overturning circulation at 34.5∘ S, J. Geophys. Res.-Ocean., 126, 5, https://doi.org/10.1029/2020JC016947, 2021. a
Kirchner, K., Rhein, M., Hüttl-Kabus, S., and Böning, C. W.: On
the spreading of South Atlantic Water into the Northern Hemisphere, J.
Geophys. Res.-Ocean., 114, C05019, https://doi.org/10.1029/2008JC005165, 2009. a
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
Latif, M., Böning, C., Willebrand, J., Biastoch, A., Dengg, J.,
Keenlyside, N., Schwecjendiek, U., and Madec, G.: Is the thermohaline
circulation changing?, J. Clim., 19, 4631–4637,
https://doi.org/10.1175/JCLI3876.1, 2006. a
Lavender, K. L., Davis, R. E., and Owens, W. B.: Mid-depth recirculation
observed in the interior Labrador and Irminger seas by direct velocity
measurements, Nature, 407, 66–69, https://doi.org/10.1038/35024048, 2000. a
Le Bras, I. A., Yashayaev, I., and Toole, J. M.: Tracking Labrador Sea Water
property signals along the Deep Western Boundary Current, J. Geophys. Res.-Ocean., 122, 5348–5366, https://doi.org/10.1002/2017JC012921, 2017. a
Lee, T. N. and Williams, E.: Wind-Forced Transport Fluctuations of the Florida
Current, J. Phys. Oceanogr., 18, 937–946,
https://doi.org/10.1175/1520-0485(1988)018<0937:wftfot>2.0.co;2, 1988. a
Legg, S., Hallberg, R. W., and Girton, J. B.: Comparison of entrainment in
overflows simulated by z-coordinate, isopycnal and non-hydrostatic models,
Ocean Model., 11, 69–97, https://doi.org/10.1016/j.ocemod.2004.11.006, 2006. a, b, c
Lemarié, F.: NEMO/AGRIF Nesting tools, User’s Guide (30 January 2006), available at: http://forge.ipsl.jussieu.fr/nemo/attachment/wiki/Users/SetupNewConfiguration/AGRIF-nesting-tool/doc_nesting_tools.pdfforge.ipsl.jussieu.fr/nemo/attachment/ (last access: 25 August 2021), 2006. a
Levitus, S., Boyer, T. P., Conkright, M. E., Brien, T. O., Antonov, J.,
Stephens, C., Stathoplos, L., Johnson, D., and Gelfeld, R.: World Ocean Database 1998, Vol. 1, Introduction, NOAA Atlas NESDIS 18, U.S. Government Printing Office, Washington, D.C., 1998. a
Locarnini, R. A., Mishonov, A. V., Antonov, J. I., Boyer, T. P., Garcia, H. E.,
Baranova, O. K., Zweng, M. M., Paver, C. R., Reagan, J. R., Johnson, D. R.,
Hamilton, M., Seidov, D., and Levitus, S.: World ocean atlas 2013,
Vol. 1, NOAA Atlas, Temperature, 73, https://doi.org/10.7289/V55X26VD, 2013. a
Lozier, M. S.: Deconstructing the conveyor belt, Science, 328,
1507–1511, https://doi.org/10.1126/science.1189250, 2010. a
Lozier, M. S., Gary, S. F., and Bower, A. S.: Simulated pathways of the
overflow waters in the North Atlantic: Subpolar to subtropical export, Deep-Sea
Res. Pt. II, 85, 147–153,
https://doi.org/10.1016/j.dsr2.2012.07.037, 2013. a
Lozier, M. S., Bacon, S., Bower, A. S., Cunningham, S. A., De Jong, M. F.,
De Steur, L., De Young, B., Fischer, J., Gary, S. F., Greenan, B. J.,
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, Bull. Am. Meteorol. Soc., 98,
737–752, https://doi.org/10.1175/BAMS-D-16-0057.1, 2017. a
Lozier, M. S., Li, F., Bacon, S., Bahr, F., Bower, A. S., Cunningham, S. A.,
De Jong, M. F., De Steur, L., DeYoung, B., Fischer, J., Gary, S. F.,
Greenan, B. J., Holliday, N. P., Houk, A., Houpert, L., Inall, M. E., Johns,
W. E., Johnson, H. L., Johnson, C., Karstensen, J., Koman, G., Le Bras,
I. A., Lin, X., Mackay, N., Marshall, D. P., Mercier, H., Oltmanns, M.,
Pickart, R. S., Ramsey, A. L., Rayner, D., Straneo, F., Thierry, V., Torres,
D. J., Williams, R. G., Wilson, C., Yang, J., Yashayaev, I., and Zhao, J.: A
sea change in our view of overturning in the subpolar North Atlantic,
Science, 363, 516–521, https://doi.org/10.1126/science.aau6592, 2019. a
Madec, G.: NEMO ocean engine, Note du Pôle modélisation, Inst.
Pierre-Simon Laplace, p. 406, 2016. a
Maltrud, M. E., Smith, R. D., Semtner, A. J., and Malone, R. C.: Global
eddy-resolving ocean simulations driven by 1985–1995 atmospheric winds, J.
Geophys. Res.-Ocean., 103, 30825–30853, https://doi.org/10.1029/1998jc900013,
1998. a
Martin, T.: Runoff remapping for ocean model forcing, GEOMAR [data set], https://doi.org/10.3289/SW_2_2021, last access: 27 August 2021. a
Matthes, K., Biastoch, A., Wahl, S., Harlaß, J., Martin, T., Brücher,
T., Drews, A., Ehlert, D., Getzlaff, K., Krüger, F., Rath, W.,
Scheinert, M., U. Schwarzkopf, F., Bayr, T., Schmidt, H., and Park, W.:
The Flexible Ocean and Climate Infrastructure version 1 (FOCI1): Mean state
and variability, Geosci. Model Dev., 13, 2533–2568,
https://doi.org/10.5194/gmd-13-2533-2020, 2020. a
McCarthy, G., Frajka-Williams, E., Johns, W. E., Baringer, M. O., Meinen,
C. S., Bryden, H. L., Rayner, D., Duchez, A., Roberts, C., and Cunningham,
S. A.: Observed interannual variability of the Atlantic meridional
overturning circulation at 26.5∘ N, Geophys. Res. Lett., 39, L19609,
https://doi.org/10.1029/2012GL052933, 2012. 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, 2010. a
Meinen, C. S., Speich, S., Piola, A. R., Ansorge, I., Campos, E.,
Kersalé, M., Terre, T., Chidichimo, M. P., Lamont, T., Sato, O. T.,
Perez, R. C., Valla, D., van den Berg, M., Le Hénaff, M., Dong, S.,
and Garzoli, S. L.: Meridional Overturning Circulation Transport Variability
at 34.5∘ S During 2009–2017: Baroclinic and Barotropic Flows and the
Dueling Influence of the Boundaries, Geophys. Res. Lett., 45, 4180–4188,
https://doi.org/10.1029/2018GL077408, 2018. a, b, c
Mertens, C., Rhein, M., Walter, M., Böning, C. W., Behrens, E., Kieke,
D., Steinfeldt, R., and Stöber, U.: Circulation and transports in the
Newfoundland Basin, western subpolar North Atlantic, J. Geophys. Res.-Ocean., 119, 7772–7793, https://doi.org/10.1002/2014JC010019, 2014. a
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
Msadek, R., Johns, W. E., Yeager, S. G., Danabasoglu, G., Delworth, T. L., and
Rosati, A.: The Atlantic meridional heat transport at 26.5∘ N and its
relationship with the MOC in the RAPID array and the GFDL and NCAR coupled
models, J. Clim., 26, 4335–4356, https://doi.org/10.1175/JCLI-D-12-00081.1, 2013. a
NEMO System Team: NEMO version 3.6 [data set], available at: https://forge.ipsl.jussieu.fr/nemo/svn/NEMO/releases/release-3.6, last access: 27 August 2021. 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. a
Peña-Molino, B., Joyce, T. M., and Toole, J. M.: Variability in the Deep
Western boundary current: Local versus remote forcing, J. Geophys. Res.-Ocean., 117, C12022, https://doi.org/10.1029/2012JC008369, 2012. a
Penduff, T., Le Sommer, J., Barnier, B., Treguier, A. M., Molines, J. M., and
Madec, G.: Influence of numerical schemes on current-topography interactions
in
Rabe, B., Karcher, M., Kauker, F., Schauer, U., Toole, J. M., Krishfield,
R. A., Pisarev, S., Kikuchi, T., and Su, J.: Arctic Ocean basin liquid
freshwater storage trend 1992–2012, Geophys. Res. Lett., 41, 961–968,
https://doi.org/10.1002/2013GL058121, 2014. a
Rahmstorf, S. and Willebrand, J.: The role of temperature feedback in
stabilizing the thermohaline circulation, J. Phys. Oceanogr.,
25, 787–805, 1995. a
Rayner, N. A., Parker, D. E., Horton, E. B., Folland, C. K., Alexander, L. V.,
Rowell, D. P., Kent, E. C., and Kaplan, A.: Global analyses of sea surface
temperature, sea ice, and night marine air temperature since the late
nineteenth century, J. Geophys. Res.-Atmos., 108, 4407,
https://doi.org/10.1029/2002jd002670, 2003. a
Reichstein, M., Camps-Valls, G., Stevens, B., Jung, M., Denzler, J.,
Carvalhais, N., and Prabhat: Deep learning and process understanding for
data-driven Earth system science, Nature, 566, 195–204,
https://doi.org/10.1038/s41586-019-0912-1, 2019. a
Rossby, T., Flagg, C., Chafik, L., Harden, B., and Søiland, H.: A Direct
Estimate of Volume, Heat, and Freshwater Exchange Across the
Greenland‐Iceland‐Faroe‐Scotland Ridge, J. Geophys.
Res.-Ocean., 123, 7139–7153, 2018. a
Roullet, G. and Madec, G.: Salt conservation, free surface and varying levels:
a new formulation for ocean general circulation models, J. Geophys. Res.,
105, 23927–23942, 2000. a
Rühs, S., Getzlaff, K., Durgadoo, J. V., Biastoch, A., and Böning,
C. W.: On the suitability of North Brazil Current transport estimates for
monitoring basin-scale AMOC changes, Geophys. Res. Lett., 42,
8072–8080, https://doi.org/10.1002/2015GL065695, 2015. a, b, c
Rühs, S., Oliver, E. C. J., Biastoch, A., Böning, C. W., Dowd, M.,
Getzlaff, K., Martin, T., and Myers, P. G.: Changing spatial patterns of
deep convection in the subpolar North Atlantic, J. Geophys. Res.-Ocean.,
126, e2021JC017245, https://doi.org/10.1029/2021jc017245, 2021. a, b
Schott, F. and Brandt, P.: Circulation and deep water export of the subpolar
North Atlantic during the 1990's, in: Ocean Circulation: Mechanisms and Impacts – Past and Future Changes of Meridional Overturning, edited by: Schmittner, A., Chiang, J. C. H., and Hemming, S. R., Vol.
173 of Geophysical Monograph Series,
Washington, DC, 91–118, 2007. a
Schott, F. A., Mccreary Jr., J. P., and Johnson, G. C.: Shallow Overturning
Circulations of the Tropical-Subtropical Oceans, American
Geophysical Union (AGU), in: Earth's Climate: The Ocean-Atmosphere Interaction, Vol. 147,
edited by: Wang, C., Xie, S. P., and Carton, J. A., Geophysical Monograph Series, 261–304, https://doi.org/10.1029/147GM15, 2004. a
Schubert, R., Biastoch, A., Cronin, M. F., and Greatbatch, R. J.:
Instability-driven benthic storms below the separated gulf stream and the
North Atlantic current in a high-resolution ocean model, J. Phys. Oceanogr.,
48, 2283–2303, https://doi.org/10.1175/JPO-D-17-0261.1, 2018. a
Schulzki, T., Getzlaff, K., and Biastoch, A.: On the Variability of the DWBC
Transport Between 26.5∘ N and 16∘ N in an Eddy‐Rich Ocean
Model, J. Geophys. Res.-Ocean., 126, e2021JC017372,
https://doi.org/10.1029/2021jc017372, 2021. a, b
Schwarzkopf, F. U.: Ventilation pathways in the tropical Atlantic and Pacific
Oceans with a focus on the Oxygen Minimum Zones: development and application
of a nested high-resolution global model system, Phd/doctoral thesis,
Christian-Albrechts-Universität Kiel, available at:
http://oceanrep.geomar.de/34702/ (last access: 25 August 2021), 2016. a
Schwarzkopf, F. U., Biastoch, A., Böning, C. W., Chanut, J., Durgadoo,
J. V., Getzlaff, K., Harlaß, J., Rieck, J. K., Roth, C., Scheinert,
M. M., and Schubert, R.: The INALT family – A set of high-resolution nests
for the Agulhas Current system within global NEMO ocean/sea-ice
configurations, Geosci. Model Dev., 12, 3329–3355,
https://doi.org/10.5194/gmd-12-3329-2019, 2019. a, b, c, d
Send, U., Lankhorst, M., and Kanzow, T.: Observation of decadal change in the
Atlantic meridional overturning circulation using 10 years of continuous
transport data, Geophys. Res. Lett., 38, L24606, https://doi.org/10.1029/2011GL049801,
2011. a
Sinha, B., Smeed, D. A., McCarthy, G., Moat, B. I., Josey, S. A., Hirschi,
J. J., Frajka-Williams, E., Blaker, A. T., Rayner, D., and Madec, G.: The
accuracy of estimates of the overturning circulation from basin-wide mooring
arrays, Prog. Oceanogr., 160, 101–123,
https://doi.org/10.1016/j.pocean.2017.12.001, 2018. a
Smith, R. D., Maltrud, M. E., Bryan, F. O., and Hecht, M. W.: Numerical
simulation of the North Atlantic Ocean at
Solodoch, A., McWilliams, J. C., Stewart, A. L., Gula, J., and Renault, L.:
Why does the deep western boundary current ‘‘leak” around flemish
cap?, J. Phys. Oceanogr., 50, 1989–2016, https://doi.org/10.1175/JPO-D-19-0247.1,
2020. a
Sonnewald, M., Wunsch, C., and Heimbach, P.: Unsupervised Learning Reveals
Geography of Global Ocean Dynamical Regions, Earth Sp. Sci., 6, 784–794,
https://doi.org/10.1029/2018EA000519, 2019. a
Srokosz, M., Danabasoglu, G., and Patterson, M.: Atlantic Meridional
Overturning Circulation: Reviews of Observational and Modeling Advances –
an Introduction, J. Geophys. Res.-Ocean., 126, 1, https://doi.org/10.1029/2020jc016745, 2020. a
Steele, M., Morley, R., and Ermold, W.: PHC: A global ocean hydrography with a
high quality Arctic Ocean, J. Clim., 14, 2079–2087, 2001. a
Steinle, L., Graves, C. A., Treude, T., Ferré, B., Biastoch, A.,
Bussmann, I., Berndt, C., Krastel, S., James, R. H., Behrens, E.,
Böning, C. W., Greinert, J., Sapart, C. J., Scheinert, M., Sommer, S.,
Lehmann, M. F., and Niemann, H.: Water column methanotrophy controlled by a
rapid oceanographic switch, Nat. Geosci., 8, 378–382,
https://doi.org/10.1038/ngeo2420, 2015. a
Stommel, H.: The abyssal circulation, Deep-Sea Res., 5, 80–82,
https://doi.org/10.1016/S0146-6291(58)80014-4, 1958. a
Thoma, M., Gerdes, R., Greatbatch, R. J., and Ding, H.: Partially coupled
spin-up of the MPI-ESM: implementation and first results, Geosci. Model
Dev., 8, 51–68, https://doi.org/10.5194/gmd-8-51-2015, 2015. a
Toole, J. M., Andres, M., Le Bras, I. A., Joyce, T. M., and McCartney, M. S.:
Moored observations of the Deep Western Boundary Current in the NW Atlantic:
2004–2014, J. Geophys. Res.-Ocean., 122, 7488–7505,
https://doi.org/10.1002/2017JC012984, 2017. a
Treguier, A. M., Theetten, S., Chassignet, E. P., Penduff, T., Smith, R.,
Talley, L., Beismann, J. O., and Böning, C.: The North Atlantic
subpolar gyre in four high-resolution models, J. Phys. Oceanogr., 35,
757–774, https://doi.org/10.1175/JPO2720.1, 2005. a
Tsujino, H., Urakawa, S., Nakano, H., Small, R. J., Kim, W. M., Yeager, S. G.,
Danabasoglu, G., Suzuki, T., Bamber, J. L., Bentsen, M., Böning, C. W.,
Bozec, A., Chassignet, E. P., Curchitser, E., Boeira Dias, F., Durack,
P. J., Griffies, S. M., Harada, Y., Ilicak, M., Josey, S. A., Kobayashi, C.,
Kobayashi, S., Komuro, Y., Large, W. G., Le Sommer, J., Marsland, S. J.,
Masina, S., Scheinert, M., Tomita, H., Valdivieso, M., and Yamazaki, D.:
JRA-55 based surface dataset for driving ocean–sea-ice models (JRA55-do),
Ocean Model., 130, 79–139, https://doi.org/10.1016/j.ocemod.2018.07.002, 2018. a, b
Tsujino, H., Urakawa, L. S., Griffies, S. M., Danabasoglu, G., Adcroft, A. J., Amaral, A. E., Arsouze, T., Bentsen, M., Bernardello, R., Böning, C. W., Bozec, A., Chassignet, E. P., Danilov, S., Dussin, R., Exarchou, E., Fogli, P. G., Fox-Kemper, B., Guo, C., Ilicak, M., Iovino, D., Kim, W. M., Koldunov, N., Lapin, V., Li, Y., Lin, P., Lindsay, K., Liu, H., Long, M. C., Komuro, Y., Marsland, S. J., Masina, S., Nummelin, A., Rieck, J. K., Ruprich-Robert, Y., Scheinert, M., Sicardi, V., Sidorenko, D., Suzuki, T., Tatebe, H., Wang, Q., Yeager, S. G., and Yu, Z.: Evaluation of global ocean–sea-ice model simulations based on the experimental protocols of the Ocean Model Intercomparison Project phase 2 (OMIP-2), Geosci. Model Dev., 13, 3643–3708, https://doi.org/10.5194/gmd-13-3643-2020, 2020. a, b, c, d
Van Sebille, E., Johns, W. E., and Beal, L. M.: Does the vorticity flux from
Agulhas rings control the zonal pathway of NADW across the South Atlantic?,
J. Geophys. Res.-Ocean., 117, C05037, https://doi.org/10.1029/2011JC007684, 2012. 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
Wunsch, C. and Heimbach, P.: Two decades of the atlantic meridional
overturning circulation: Anatomy, variations, extremes, prediction, and
overcoming its limitations, J. Clim., 26, 7167–7186,
https://doi.org/10.1175/JCLI-D-12-00478.1, 2013. a
Xu, X., Schmitz, W. J., Hurlburt, H. E., Hogan, P. J., and Chassignet, E. P.:
Transport of Nordic Seas overflow water into and within the Irminger Sea: An
eddy-resolving simulation and observations, J. Geophys. Res.-Ocean., 115,
C12048, https://doi.org/10.1029/2010JC006351, 2010. a
Yashayaev, I.: Hydrographic changes in the Labrador Sea, 1960–2005, Prog.
Oceanogr., 73, 242–276, https://doi.org/10.1016/j.pocean.2007.04.015, 2007. a
Yeager, S. and Danabasoglu, G.: The origins of late-twentieth-century
variations in the large-scale North Atlantic circulation, J. Clim., 27,
3222–3247, https://doi.org/10.1175/JCLI-D-13-00125.1, 2014.
a
Zalesak, S. T.: Fully multidimensional flux-corrected transport algorithms for
fluids, J. Comput. Phys., 31, 335–362, 1979. a
Zantopp, R., Fischer, J., Visbeck, M., and Karstensen, J.: From interannual to
decadal: 17 years of boundary current transports at the exit of the Labrador
Sea, J. Geophys. Res.-Ocean., 122, 1724–1748, https://doi.org/10.1002/2016JC012271,
2017. a, b, c, d
Zou, S., Lozier, S., Zenk, W., Bower, A., and Johns, W.: Observed and modeled
pathways of the Iceland Scotland Overflow Water in the eastern North
Atlantic, Prog. Oceanogr., 159, 211–222,
https://doi.org/10.1016/j.pocean.2017.10.003, 2017. a
Zou, S., Lozier, M. S., and Buckley, M.: How Is Meridional Coherence
Maintained in the Lower Limb of the Atlantic Meridional Overturning
Circulation?, Geophys. Res. Lett., 46, 244–252, https://doi.org/10.1029/2018GL080958,
2019. a
Zweng, M. M., Reagan, J. R., Antonov, J. I., Locarnini, R. A., Mishonov, A. V.,
Boyer, T. P., Garcia, H. E., Baranova, O. K., Johnson, D. R., Seidov 1948-,
D., Biddle, M. M., and Levitus, S.: World ocean atlas 2013, Vol. 2,
Salinity, NOAA Atlas NESDIS series, no. 74, https://doi.org/10.7289/V5251G4D, 2013. a
Short summary
The Atlantic Meridional Overturning Circulation (AMOC) quantifies the impact of the ocean on climate and climate change. Here we show that a high-resolution ocean model is able to realistically simulate ocean currents. While the mean representation of the AMOC depends on choices made for the model and on the atmospheric forcing, the temporal variability is quite robust. Comparing the ocean model with ocean observations, we able to identify that the AMOC has declined over the past two decades.
The Atlantic Meridional Overturning Circulation (AMOC) quantifies the impact of the ocean on...
