Climate Dynamics

, Volume 53, Issue 3–4, pp 2339–2353 | Cite as

Is the boreal spring tropical Atlantic variability a precursor of the Equatorial Mode?

  • Marta Martín-ReyEmail author
  • Alban Lazar


The Equatorial Mode (EM) governs the tropical Atlantic inter-annual variability during boreal summer. It has profound impacts on the climate of adjacent and remote areas. However, predicting the EM is one of the most challenging and intriguing issues for the scientific community. Recent studies have suggested a possible connection between the boreal spring Meridional Mode (MM) and the EM through ocean wave propagation. Here, we use a set of sensitivity experiments with a medium-resolution ocean model to determine the precursor role of a MM to create equatorial SST variability. Our results demonstrate that boreal summer equatorial SSTs following a MM, are subject to two counteracting effects: the local wind forcing and remotely-excited oceanic waves. For a positive MM, the anomalous easterly winds blowing along the equator, shallow the thermocline, cooling the sea surface via vertical diffusion and meridional advection. Anomalous wind curl excites a downwelling Rossby wave north of equator, which is reflected at the western boundary becoming an equatorial Kelvin wave (KW). This downwelling KW propagates eastward, deepening the thermocline and activating the thermocline feedbacks responsible for the equatorial warming. Moreover, the local wind forcing and RW-reflected mechanism have a significant and comparable impact on the equatorial SST variability. Changes in the intensity and persistence of these distinct forcings will determine the equatorial SST response during boreal summer. Our results give a step forward to the improvement of the EM predictability.


Tropical Atlantic Meridional Mode Equatorial Mode Ocean waves SST variability 



The research leading to these results received funding from the EU FP7/2007-2013 under Grant Agreement 603521 (PREFACE project), the MORDICUS grant under contract ANR-13-SENV-0002-01, CNES/EUMETSAT (CNES—DIA/TEC-2016.8595, EUM/LEO-JAS3/DOC/16/852054) and the MSCA-IF-EF-ST FESTIVAL (H2020-EU project 797236). The observed SSTs from HadISST dataset were provided by the MetOffice Hadley Centre, from its website at The data from the INTER, MM-REF, MM-WIND and MM-WAVE simulations are available from the authors upon request.


  1. Amaya DJ, DeFlorio MJ, Miller AJ, Xie S-P (2016) WES feedback and the Atlantic Meridional Mode: observations and CMIP5 comparisons. Clim Dyn 49(5–6):1665–1679Google Scholar
  2. Andreoli RV, Kayano MT (2003) Evolution of the equatorial and dipole modes of the sea-surface temperature in the Tropical Atlantic at decadal scale. Meteorol Atmos Phys 83:277–285Google Scholar
  3. Bjerknes J (1969) Atmospheric teleconnections from the equatorial Pacific. Mon Weather Rev 97:163–172CrossRefGoogle Scholar
  4. Brandt P, Funk A, Hormann V, Dengler M, Greatbatch RJ, Toole JM (2011) Interannual atmospheric variability forced by the deep equatorial Atlantic Ocean. Nature 473:497CrossRefGoogle Scholar
  5. Brodeau L, Barnier B, Treguier AM, Penduff T, Gulev S (2010) An ERA40-based atmospheric forcing for global ocean circulation models. Ocean Model 31:88–104CrossRefGoogle Scholar
  6. Burmeister K, Brandt P, Lübbecke J (2016) Revisiting the cause of the eastern equatorial Atlantic cold event in 2009. J Geophys Res Oceans 121:4777–4789CrossRefGoogle Scholar
  7. Butterworth S (1930) On the theory of filter amplifiers. Exp Wirel Wirel Eng 7:536–541Google Scholar
  8. Carton JA, Huang B (1994) Warm events in the Tropical Atlantic. J Phys Oceanogr 24:888–903CrossRefGoogle Scholar
  9. Carton JA., Cao X, Giese BS, Da Silva AM (1996) Decadal and interannual SST variability in the tropical Atlantic Ocean. J Phys Oceanogr 26(7):1165–1175CrossRefGoogle Scholar
  10. Chang P, Ji L, Li H (1997) A decadal climate variation in the tropical Atlantic Ocean from thermodynamic air-sea interactions. Nature 385(6616):516CrossRefGoogle Scholar
  11. Czaja A, Van der Vaart P, Marshall J (2002) A diagnostic study of the role of remote forcing in Tropical Atlantic variability. J Clim 15:3280–3290CrossRefGoogle Scholar
  12. Faye S, Lazar A, Sow B, Gaye A (2015) A model study of the seasonality of sea surface temperature and circulation in the Atlantic North-eastern Tropical Upwelling System. Front Phys 3:76CrossRefGoogle Scholar
  13. Foltz GR, McPhaden MJ (2010a) Interaction between the Atlantic meridional and Niño modes. Geophys Res Lett 37:L18604. Google Scholar
  14. Foltz GR, McPhaden MJ (2010b) Abrupt equatorial wave-induced cooling of the Atlantic cold tongue in 2009. Geophys Res Lett. Google Scholar
  15. Foltz GR, Grodsky SA, Carton JA, McPhaden MJ (2003) Seasonal mixed layer heat budget of the tropical Atlantic Ocean. J Geophys Res Oceans 108:3146CrossRefGoogle Scholar
  16. Handoh IC, Bigg GR, Matthews AJ, Stevens DP (2006) Interannual variability of the Tropical Atlantic independent of and associated with ENSO: Part II. The South Tropical Atlantic. Int J Climatol 26:1957–1976CrossRefGoogle Scholar
  17. Huang B, Shukla J (1997) Characteristics of the interannual and decadal variability in a general circulation model of the Tropical Atlantic Ocean. J Phys Oceanogr 27:1693–1712CrossRefGoogle Scholar
  18. Illig S et al (2004) Interannual long equatorial waves in the tropical Atlantic from a high-resolution ocean general circulation model experiment in 1981–2000. J Geophys Res Oceans. Google Scholar
  19. Jin D, Huo L (2018) Influence of tropical Atlantic sea surface temperature anomalies on the East Asian summer monsoon. Q J R Meteorol Soc 144:1490–1500CrossRefGoogle Scholar
  20. Jouanno J, Hernandez O, Sanchez-Gomez E (2017) Equatorial Atlantic interannual variability and its relation to dynamic and thermodynamic processes. Earth Syst Dyn 8:1061–1069CrossRefGoogle Scholar
  21. Keenlyside NS, Latif M (2007) Understanding equatorial Atlantic interannual variability. J Clim 20:131–142CrossRefGoogle Scholar
  22. Kucharski F, Bracco A, Yoo JH, Molteni F (2008) Atlantic forced component of the Indian monsoon interannual variability. Geophys Res Lett 35:L04706CrossRefGoogle Scholar
  23. Kucharski F, Bracco A, Yoo JH, Tompkins AM, Feudale L, Ruti P, Dell’Aquila A (2009) A Gill–Matsuno-type mechanism explains the tropical Atlantic influence on African and Indian monsoon rainfall. Q J R Meteorol Soc 135:569–579CrossRefGoogle Scholar
  24. Latif M, Grötzner A (2000) The equatorial Atlantic oscillation and its response to ENSO. Clim Dyn 16:213–218CrossRefGoogle Scholar
  25. Losada T, Rodríguez-Fonseca B, Kucharski F (2012a) Tropical influence on the summer Mediterranean climate. Atmos Sci Lett 13:36–42CrossRefGoogle Scholar
  26. Losada T, Rodriguez-Fonseca B, Mohino E, Bader J, Janicot S, Mechoso CR (2012b) Tropical SST and Sahel rainfall: a non-stationary relationship. Geophys Res Lett 39:L12705CrossRefGoogle Scholar
  27. Lübbecke J, McPhaden MJ (2012) On the inconsistent relationship between Pacific and Atlantic Niños. J Clim 25:4294–4303CrossRefGoogle Scholar
  28. Lübbecke JF, McPhaden MJ (2013) A comparative stability analysis of Atlantic and Pacific Niño modes. J Clim 26:5965–5980CrossRefGoogle Scholar
  29. Lübbecke J, Böning CW, Keenlyside NS, Xie S-P (2010) On the connection between Benguela and equatorial Atlantic Niños and the role of the South Atlantic anticyclone. J Geophys Res Oceans 115:C09015CrossRefGoogle Scholar
  30. Lübbecke J, Rodríguez-Fonseca B, Richter I, Martín-Rey M, Losada T, Polo I, Keenlyside N (2018) Equatorial Atlantic variability—modes, mechanisms and global teleconnections. WIREs Clim Change 9(4):e527. CrossRefGoogle Scholar
  31. Madec G (2008) NEMO ocean engine, Note du Pole de modèlisationGoogle Scholar
  32. Martín-Rey M, Rodríguez-Fonseca B, Polo I, Kucharski F (2014) On the Atlantic-Pacific Niños connection: a multidecadal modulated mode. Clim Dyn 43:3163–3178CrossRefGoogle Scholar
  33. Martín-Rey M, Rodríguez-Fonseca B, Polo I (2015) Atlantic opportunities for ENSO prediction. Geophys Res Lett 42:6802–6810CrossRefGoogle Scholar
  34. Martín-Rey M, Polo I, Rodríguez-Fonseca B, Lazar A, Losada T (2019) Ocean dynamics shapes the structure and timing of tropical Atlantic variability modes. Geophys Res Lett (under review) Google Scholar
  35. Mohino E, Losada T (2015) Impacts of the Atlantic equatorial mode in a warmer climate. Clim Dyn 45:2255–2271CrossRefGoogle Scholar
  36. Murtugudde RG, Ballabrera-Poy J, Beauchamp J, Busalacchi AJ (2001) Relationship between zonal and meridional modes in the tropical Atlantic. Geophys Res Lett 28:4463–4466CrossRefGoogle Scholar
  37. Nnamchi H, Li J, Kucharski F, Kang I-S, Keenlyside NS, Chang P, Farneti R (2015) Thermodynamic controls of the Atlantic Niño. Nat Commun 6:8895CrossRefGoogle Scholar
  38. Nnamchi HC, Li J, Kucharski F, Kang IS, Keenlyside NS, Chang P, Farneti R (2016) An equatorial-extratropical dipole structure of the Atlantic Niño. J Clim 29:7295–7311CrossRefGoogle Scholar
  39. Nobre P, Shukla J (1996) Variations in sea surface temperatura, wind stress, and rainfall over the tropical Atlantic and South America. J Clim 9:2464–2479CrossRefGoogle Scholar
  40. Peter A-C et al (2006) A model study of the seasonal mixed layer heat budget in the equatorial Atlantic. J Geophys Res Oceans 111:C06014Google Scholar
  41. Polo I, Rodríguez-Fonseca B, Losada T, García-Serrano J (2008a) Tropical Atlantic variability modes (1979–2002). Part I: time-evolving SST modes related to West African rainfall. J Clim 21:6457–6475CrossRefGoogle Scholar
  42. Polo I, Lazar A, Rodriguez-Fonseca B, Arnault S (2008b) Oceanic Kelvin waves and tropical Atlantic intraseasonal variability: 1. Kelvin wave characterization. J Geophys Res Oceans 113:07009CrossRefGoogle Scholar
  43. Polo I, Lazar A, Rodriguez-Fonseca B, Mignot J (2015a) Growth and decay of the equatorial Atlantic SST mode by means of closed heat budget in a coupled general circulation model. Front Earth Sci 3:37CrossRefGoogle Scholar
  44. Polo I, Martín-Rey M, Rodriguez-Fonseca B, Kucharski F, Mechoso C (2015b) Processes in the Pacific La Niña onset triggered by the Atlantic Niño. Clim Dyn 44:115–131CrossRefGoogle Scholar
  45. Rayner NA et al (2003) Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J Geophys Res Atmos 108:4407CrossRefGoogle Scholar
  46. Richter I, Behera SK, Masumoto Y, Taguchi B, Sasaki H, Yamagata T (2013) Multiple causes of interannual sea surface temperature variability in the equatorial Atlantic Ocean. Nat Geosci 6:43–47CrossRefGoogle Scholar
  47. Rodríguez-Fonseca B, Polo I, García-Serrano J, Losada T, Mohino E, Mechoso CR, Kucharski F (2009) Are Atlantic Niños enhancing Pacific ENSO events in recent decades? Geophys Res Lett 36:L20705CrossRefGoogle Scholar
  48. Rodríguez-Fonseca B et al (2015) Variability and predictability of West African droughts: a review on the role of sea surface temperature anomalies. J Clim 28:4034–4060CrossRefGoogle Scholar
  49. Ruiz-Barradas A, Carton JA, Nigam S (2000) Structure of interannual-to-decadal climate variability in the tropical Atlantic sector. J Clim 13:3285–3297CrossRefGoogle Scholar
  50. Servain J, Wainer I, McCreary JP, Dessier A (1999) Relationship between the equatorial and meridional modes of climatic variability in the tropical Atlantic. Geophys Res Lett 26:485–488CrossRefGoogle Scholar
  51. Suarez MJ, Schopf PS (1988) A delayed action oscillator for ENSO. J Atmos Sci 45:3283–3287CrossRefGoogle Scholar
  52. von Storch H, Zwiers F (2001) Statistical analysis in climate research. Cambridge University Press, Cambridge, p 484Google Scholar
  53. Wagner RG (1996) Mechanisms controlling variability of the interhemispheric sea surface temperature gradient in the tropical Atlantic. J Clim 9(9):2010–2019CrossRefGoogle Scholar
  54. Zebiak SE (1993) Air–sea interaction in the equatorial Atlantic Region. J Clim 6:1567–1586CrossRefGoogle Scholar
  55. Zhu J, Huang B, Wu Z (2012) The role of ocean dynamics in the interaction between the Atlantic meridional and equatorial modes. J Clim 25:3583–3598CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Laboratoire d’Oceanographie et du Climat: Expérimentation et Approches Numériques (LOCEAN)Université Pierre et Marie Curie (UPMC), Universités SorbonnesParisFrance
  2. 2.UMR5318 CECI CNRS-CERFACSToulouseFrance
  3. 3.Departamento de Oceanografía Física y TecnológicaInstituto de Ciencias del Mar (ICM-CSIC)BarcelonaSpain

Personalised recommendations