Abstract
Many previous studies have shown that unforced climate model simulations exhibit decadal-scale fluctuations in the Atlantic meridional overturning circulation (AMOC), and that this variability can have impacts on surface climate fields. However, the robustness of these surface fingerprints across different models is less clear. Furthermore, with the potential for coupled feedbacks that may amplify or damp the response, it is not known whether the associated climate signals are linearly related to the strength of the AMOC changes, or if the fluctuation events exhibit nonlinear behaviour with respect to their strength or polarity. To explore these questions, we introduce an objective and flexible method for identifying the largest natural AMOC fluctuation events in multicentennial/multimillennial simulations of a variety of coupled climate models. The characteristics of the events are explored, including their magnitude, meridional coherence and spatial structure, as well as links with ocean heat transport and the horizontal circulation. The surface fingerprints in ocean temperature and salinity are examined, and compared with the results of linear regression analysis. It is found that the regressions generally provide a good indication of the surface changes associated with the largest AMOC events. However, there are some exceptions, including a nonlinear change in the atmospheric pressure signal, particularly at high latitudes, in HadCM3. Some asymmetries are also found between the changes associated with positive and negative AMOC events in the same model. Composite analysis suggests that there are signals that are robust across the largest AMOC events in each model, which provides reassurance that the surface changes associated with one particular event will be similar to those expected from regression analysis. However, large differences are found between the AMOC fingerprints in different models, which may hinder the prediction and attribution of such events in reality.
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References
Balan Sarojini B, Gregory JM, Tailleux R, Bigg GR, Blaker AT, Cameron DR, Edwards NR, Megann AP, Shaffrey LC, Sinha B (2011) High frequency variability of the Atlantic meridional overturning circulation. Ocean Sci 7:471–486. doi:10.5194/os-7-471-2011
Bingham RJ, Hughes CW, Roussenov V, Williams RG (2007) Meridional coherence of the North Atlantic meridional overturning circulation. Geophys Res Lett 34: doi:10.1029/2007GL031731
Born A, Stocker TF, Raible CC, Levermann A (2013) Is the Atlantic subpolar gyre bistable in comprehensive coupled climate models? Clim Dyn 40:2993–3007. doi:10.1007/s00382-012-1525-7
Bower AS, Lozier MS, Gary SF, Böning CW (2009) Interior pathways of the North Atlantic meridional overturning circulation. Nature 459:243–248
Condron A, Renfrew IA (2012) The impact of polar mesoscale storms on northeast Atlantic Ocean circulation. Nat Geosci 6:34–37
Cunningham SA, Kanzow T, Rayner D, Baringer MO, Johns WE, Marotzke J, Longworth HR, Grant EM, Hirschi JJ-M, Beal LM, Meinen CS, Bryden HL (2007) Temporal variability of the Atlantic Meridional overturning circulation at 26.5°N. Science 317:935–937
Czaja A, Frankignoul C (1999) Influence of the North Atlantic SST on the atmospheric circulation. Geophys Res Lett 26:2969–2972
Czaja A, Frankignoul C (2002) Observed impact of Atlantic SST anomalies on the North Atlantic oscillation. J Clim 15:606–623
de Coëtlogon G, Frankignoul C, Bentsen M, Delon C, Haak H, Masina S, Pardaens A (2006) Gulf stream variability in five Oceanic general circulation models. J Phys Oceanogr 36:2119–2135
Delworth T, Manabe S, Stouffer RJ (1993) Interdecadal variations of the thermohaline circulation in a coupled Ocean–Atmosphere model. J Clim 6:1993–2011
Delworth T, Broccoli AJ, Rosati A, Stouffer RJ, Balaji V, Beesley JA, Cooke WF, Dixon KW, Dunne J, Dunne KA, Durachta JW, Findell KL, Ginoux P, Gnanadesikan A, Gordon CT, Griffies SM, Gudgel R, Harrison MJ, Held IM, Hemler RS, Horowitz LW, Klein SA, Knutson TR, Kushner PJ, Langenhorst AR, Lee H-C, Lin S-J, Lu J, Malyshev SL, Milly PCD, Ramaswamy V, Russell J, Schwarzkopf MD, Shevliakova E, Sirutis JJ, Spelman MJ, Stern WF, Winton M, Wittenberg AT, Wyman B, Zeng F, Zhang R (2006) GFDL’s CM2 global coupled climate models. Part I: formulation and simulation characteristics. J Clim 19:643–674
Delworth TL, Mann ME (2000) Observed and simulated multidecadal variability in the Northern Hemisphere. Clim Dyn 16:661–676
Delworth TL, Zhang R, Mann ME (2007) Decadal to centennial variability of the Atlantic from observations and models. Ocean circulation: mechanisms and impacts, geophysical monograph series 173. American Geophysical Union, Washington, pp 131–148
Dong B, Sutton RT (2005) Mechanism of interdecadal thermohaline circulation variability in a coupled Ocean–Atmosphere GCM. J Clim 18:1117–1135
Gamiz-Fortis SR, Sutton RT (2007) Quasi-periodic fluctuations in the Greenland-Iceland-Norwegian Seas region in a coupled climate model. Ocean Dyn 77:541–557
Gastineau G, Frankignoul C (2012) Cold-season atmospheric response to the natural variability of the Atlantic meridional overturning circulation. Clim Dyn 39:37–57. doi:10.1007/s00382-011-1109-y
Gastineau G, D’Andrea F, Frankignoul C (2013) Atmospheric response to the North Atlantic Ocean variability on seasonal to decadal time scales. Clim Dyn 40:2311–2330. doi:10.1007/s00382-012-1333-0
Getzlaff J, Böning CW, Eden C, Biastoch A (2005) Signal propagation related to the North Atlantic overturning. Geophys Res Lett 32: doi:10.1029/2004GL021002
Grist JP, Josey SA, Marsh R, Good SA, Coward AC, de Cuevas B, Alderson SG, New AL, Madec G (2010) The roles of surface heat flux and ocean heat transport convergence in determining Atlantic Ocean temperature variability. Ocean Dyn 60. doi:10.1007/s10236-010-0292-4
Gordon C, Cooper C, Senior CA, Banks H, Gregory J, Johns TC, Mitchell JFB, Wood RA (2000) The simulation of SST, sea ice extents and ocean heat transports in a version of the Hadley Centre coupled model without flux adjustments. Clim Dyn 16:147–168
Griffies SM, Bryan K (1997) A predictability study of simulated North Atlantic multidecadal variability. Clim Dyn 13:459–487
Häkkinen S, Rhines PB, Worthen DL (2011) Atmospheric blocking and Atlantic multidecadal Ocean variability. Science 334:655–659
Hátún H, Sandø AB, Drange H, Hansen B, Valdimarsson H (2005) Influence of the Atlantic subpolar gyre on the thermohaline circulation. Science 309:1841–1844
Hawkins E, Sutton R (2007) Variability of the Atlantic thermohaline circulation described by three-dimensional empirical orthogonal functions. Clim Dyn 29:745–762
Hawkins E, Sutton R (2008) Potential predictability of rapid changes in the Atlantic meridional overturning circulation. Geophys Res Lett 35: doi:10.1029/2008GL034059
Hazeleger W, Severijns C, Semmler T, Ştefănescu S, Yang S, Wang X, Wyser K, Dutra E, Baldasano JM, Bintanja R, Bougeault P, Caballero R, Ekman AML, Christensen JH, van den Hurk B, Jimenez P, Jones C, Kållberg P, Koenigk T, McGrath R, Miranda P, van Noije P, Palmer T, Parodi JA, Schmith T, Selten F, Storelvmo T, Sterl A, Tapamo H, Vancoppenolle M, Viterbo P, Willèn U (2010) EC-Earth: a seamless earth-system prediction approach in action. Bull Am Meteorol Soc 91:1357–1363
Hirschi JJ-M, Blaker AT, Sinha B, Coward A, de Cuevas B, Alderson S, Madec G (2013) Chaotic variability of the meridional overturning circulation on subannual to interannual timescales. Ocean Sci 9:805–823. doi:10.5194/os-9-805-2013
Hodson DLR, Sutton R (2012) The impact of resolution on the adjustment and decadal variability of the Atlantic Meridional overturning circulation in a coupled climate model. Clim Dyn 39:3057–3073. doi:10.1007/s00382-012-1309-0
Johns WE, Baringer MO, Beal LM, Cunningham SA, Kanzow T, Bryden HL, Hirschi JJM, Marotzke J, Meinen CS, Shaw B, Curry R (2011) Continuous, array-based estimates of Atlantic Ocean heat transport at \(26.5^\circ\)N. J Clim 24:2429–2449
Johnson HL, Marshall DP (2002) A theory for the surface Atlantic response to thermohaline variability. J Phys Oceanogr 32:1121–1132
Jungclaus JH, Haak H, Latif M, Mikolajewicz U (2005) Arctic–North Atlantic interactions and multidecadal variability of the meridional overturning circulation. J Clim 18:4013–4031
Jungclaus JH, Keenlyside N, Botzet M, Haak H, Luo J-J, Latif M, Marotzke J, Mikolajewicz U, Roeckner E (2006) Ocean circulation and tropical variability in the coupled model ECHAM5/MPI-OM. J Clim 19:3952–3972
Knight JR, Allan RJ, Folland CK, Vellinga M, Mann ME (2005) A signature of persistent natural thermohaline circulation cycles in observed climate. Geophys Res Lett 32: doi:10.1029/2005GL024233
Kwon Y-O, Alexander MA, Bond NA, Frankignoul C, Nakamura H, Qiu B, Thompson L (2010) Role of the Gulf Stream and Kuroshio-Oyashio systems in large-scale atmosphere–ocean interaction: a review. J Clim 23:3249–3281
Langehaug HR, Medhaug I, Eldevik T, Otterå OH (2012) Arctic/Atlantic exchanges vie the subpolar gyre. J Clim 25:2421–2439
Lavin A, Bryden HL, Parilla G (1998) Meridional transport and heat flux variations in the subtropical North Atlantic. Global Atmos Ocean Syst 6:269–293
Lohmann K, Drange H, Bentsen M (2009) Response of the North Atlantic subpolar gyre to persistent North Atlantic oscillation like forcing. Clim Dyn 32:273–285
Lozier MS, Roussenov V, Reed MSC, Williams RG (2010) Opposing decadal changes for the North Atlantic meridional overturning circulation. Nat Geosci 3:728–734
MacMartin DG, Tziperman E, Zanna L (2013) Frequency-domain multi-model analysis of the response of Atlantic meridional overturning circulation to surface forcing. J Clim 26:8323–8340
Mahajan S, Zhang R, Delworth TL (2011) Impact of the Atlantic meridional overturning circulation (AMOC) on Arctic surface air temperature and sea ice variability. J Clim 24:6573–6581
Marti O, Braconnot P, Dufresne J-L, Bellier J, Benshila R, Bony S, Brockmann P, Cadule P, Caubel A, Codron F, de Noblet N, Denvil S, Fairhead L, Fichefet T, Foujols M-A, Friedlingstein P, Goosse H, Grandpeix J-Y, Guilyardi E, Hourdin F, Idelkadi A, Kageyama M, Krinner G, Lvy C, Madec G, Mignot J, Musat I, Swingedouw D, Talandier C (2010) Key features of the IPSL ocean atmosphere model and its sensitivity to atmospheric resolution. Clim Dyn 34:1–26
McCarthy G, Frajka-Williams E, Johns WE, Baringer MO, Meinen CS, Bryden HL, Rayner D, Duchez A, Roberts C, Cunningham SA (2012) Observed interannual variability of the Atlantic meridional overturning circulation at 26.5°N. Geophys Res Lett 39: doi:10.1029/2012GL052933
Medhaug I, Furevik T (2011) North Atlantic 20th century multidecadal variability in coupled climate models: sea surface temperature and ocean overturning circulation. Ocean Sci 7:389–404
Medhaug I, Langehaug HR, Eldevik T, Furevik T, Bentsen M (2012) Mechanisms for decadal scale variability in a simulated Atlantic meridional overturning circulation. Clim Dyn 39:77–93
Menary MB, Park W, Lohmann K, Vellinga M, Palmer MD, Latif M, Jungclaus JH (2012) A multimodel comparison of centennial Atlantic meridional overturning circulation variability. Clim Dyn 38:2377–2388
Msadek R, Frankignoul C (2009) Atlantic multidecadal oceanic variability and its influence on the atmosphere in a coupled climate model. Clim Dyn 33:45–62
Msadek R, Frankignoul C, Li LZX (2011) Mechanisms of the atmospheric response to North Atlantic multidecadal variability: a model study. Clim Dyn 36:1255–1276
Msadek R, Johns WE, Yeager SG, Danabasoglu G, Delworth TL, Rosati A (2013) 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
Ortega P, Hawkins E, Sutton R (2011) Processes governing the predictability of the Atlantic meridional overturning circulation in a coupled GCM. Clim Dyn 37:1771–1782
Pohlmann H, Sienz F, Latif M (2006) Influence of the multidecadal Atlantic meridional overturning circulation variability on European climate. J Clim 19:6062–6067
Rayner D, Hirschi JJ-M, Kanzow T, Johns WE, Wright PG, Frajka-Williams E, Bryden HL, Meinen CS, Baringer MO, Marotzke J, Beal LM, Cunningham SA (2011) Monitoring the Atlantic meridional overturning circulation. Deep Sea Res 58:1744–1753
Rhines P, Häkkinen S, Josey SA (2008) Is the oceanic heat transport significant in the climate system? In: Dickson RR, Meincke J, Rhines P (eds) Arctic-subarctic ocean fluxes: defining the role of the northern Seas in climate. Springer, Dordrecht
Robson J, Sutton R, Lohmann K, Smith D, Palmer MD (2012a) Causes of the rapid warming of the North Atlantic Ocean in the mid-1990s. J Clim 25:4116–4134
Robson J, Sutton R, Smith D (2012b) Initialized decadal predictions of the rapid warming of the North Atlantic Ocean in the mid 1990s. Geophys Res Lett 39: doi:10.1029/2012GL053370
Schlesinger ME, Ramankutty N (1994) An oscillation in the global climate system of period 65–70 years. Nature 367:723–726. doi:10.1038/367723a0
Sime LC, Stevens DP, Heywood KJ, Oliver KIC (2006) A decomposition of the Atlantic meridional overturning. J Phys Oceanogr 36:2253–2270
Sinha B, Topliss B, Blaker AT, Hirschi J-M (2013) A numerical model study of the effects of interannual time scale wave propagation on the predictability of the Atlantic meridional overturning circulation. J Geophys Res Oceans 118:131–146. doi:10.1029/2012JC008334
Smith RS, Gregory JM, Osprey A (2008) A description of the FAMOUS (version XDBUA) climate model and control run. Geosci Model Dev Discuss 3:846–849
Strong C, Magnusdottir G (2010) Modeled winter sea ice variability and the North Atlantic oscillation: a multi-century perspective. Clim Dyn 34:515–525. doi:10.1007/s00382-009-0550-7
Timmermann A, Latif M, Voss R, Grötzner A (1998) Northern hemispheric interdecadal variability: a coupled air–sea mode. J Clim 11:1906–1931
Vellinga M, Wu P (2004) Low-latitude freshwater influence on centennial variability of the Atlantic thermohaline circulation. J Clim 17:4498–4511
Wouters B, Drijfhout S, Hazeleger W (2012) Interdecadal North-Atlantic meridional overturning circulation variability in EC-EARTH. Clim Dyn 39:2695–2712
Yeager S, Karspeck A, Danabasoglu G, Tribbia J, Teng H (2012) A decadal prediction case study: late twentieth-century North Atlantic ocean heat content. J Clim 25:5173–5189
Zhang R (2008) Coherent surface-subsurface fingerprint of the Atlantic meridional overturning circulation. Geophys Res Lett 35: doi:10.1029/2008GL035463
Zhang R (2010) Latitudinal dependence of Atlantic meridional overturning (AMOC) variations. Geophys Res Lett 37: doi:10.1029/2010GL044474
Zhang R, Vallis GK (2007) The role of bottom vortex stretching on the path of the North Atlantic western boundary current and on the northern recirculation gyre. J Phys Oceanogr 37:2053–2080
Acknowledgments
This work was funded by the UK Natural Environment Research Council (NERC) RAPID-WATCH RAPIT project. We are grateful to Laura Jackson for many helpful discussions and to Jon Robson and David Ferreira for comments on the manuscript. We thank MPI, IPSL, GFDL and the Met Office for making their model data available. We are grateful to Robin Smith, Daniela Matei, Juliette Mignot and Bert Wouters for the simulations of FAMOUS, ECHAM5/MPI-OM, IPSL CM4, and EC-EARTH respectively. We acknowledge the Program for Climate Model Diagnosis and Intercomparison (PCMDI) and the WCRP’s Working Group on Coupled Modelling (WGCM) for their roles in making available the WCRP CMIP3 multi-model dataset. Support of this dataset is provided by the Office of Science, U.S. Department of Energy. We thank two anonymous reviewers for comments and suggestions that improved the manuscript.
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Allison, L., Hawkins, E. & Woollings, T. An event-based approach to understanding decadal fluctuations in the Atlantic meridional overturning circulation. Clim Dyn 44, 163–190 (2015). https://doi.org/10.1007/s00382-014-2271-9
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DOI: https://doi.org/10.1007/s00382-014-2271-9