Abstract
The climatic impacts of an enhanced evaporation prescribed during 50 years in the tropical Atlantic are investigated in a coupled ocean–atmosphere general circulation model. Locally, the salinity increase leads to a rapid deepening and cooling of the surface mixed layer. This induces a deepening of the equatorial undercurrent and an intensification of the south equatorial current. A remote atmospheric response to the tropical Atlantic perturbation is detected in the North Atlantic sector after ten years. It has the form of a robust wave-like tropospheric perturbation seemingly excited by the weakening of atmospheric deep convection over the Amazonian basin. Meanwhile, the salt anomaly is carried northward by the mean oceanic circulation. It is traced up to the convection sites and then on its return path at depth towards lower latitudes. Consistent with the density increase, deep convection is enhanced after the arrival of the salt anomaly and the Atlantic meridional overturning circulation (AMOC) intensifies about 20 years after the beginning of the perturbation. The adjustment of the tropical Atlantic to the AMOC intensification then modifies its initial response to the freshwater forcing, leading to a weaker cooling in the northern tropical Atlantic than in the southern tropical Atlantic, a slight northward shift of the tropical Atlantic precipitation pattern and an intensification of the North Brazil current. On the other hand, no significant anomalous precipitations are found in the Pacific. The initial remote atmospheric response is also modulated, by an NAO-like response to the AMOC intensification.
Similar content being viewed by others
References
Black DE, Thunell RC, Kaplan A, Peterson LC, Tappa EJ (2004) A 2000-year record of Caribbean and tropical North Atlantic hydrographic variability. Paleoceanog 19. doi:10.1029/2003PA000982
Bond G, Heinrich H, Broecker W, Labeyrie L, McManus J, Andrews J, Huon S, Jantschik R, Clasen S, Simet C, Tedesco K, Klas M, Bonani G, S, and Ivy (1992) Evidence for massive discharge of icebergs into the North Atlantic Ocean during the last glacial. Nature 360:245–249
Bryden HL, Longworth HR, Cunningham SA (2005) Slowing down of the Atlantic meridional overturning circulation at 25°N. Nature 438:655–657. doi:10.1038/nature04385
Chang P, Ji L, LI H (1997) A decadal climate variation in the tropical Atlantic Ocean from thermodynamic air–sea interactions. Nature 385:516–518
Clarke PU, Pisias NG, Stocker TF, Weaver AJ (2002) The role of the thermohaline circulation in abrupt climate change. Nature 415:863–869
Cook KH, and Vizy EK, (2006) Coupled model simulations of the west african monsoon system: twentieth- and twenty-first-century simulations. J Clim 19(15):3681–3703
Cunningham AS, 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 317:935–938. doi:10.1126/science.1141304
Delworth TL, Greatbatch RJ (2000) Multidecadal thermohaline circulation variability driven by atmospheric surface flux forcing. J Clim 13:1481–1495
Deshayes J, Frankignoul C (2008) Simulated variability of the circulation in the North Atlantic from 1953 to 2003. J Clim 21:4919–4933
Eden C, Willebrand J (2001) Mechanisms of interannual to decadal variability of the North Atlantic circulation. J Clim 14:2266–2280
Fichefet T, Morales-Maqueda MAM (1997) Sensitivity of a global sea ice model to the treatment of ice thermodynamics and dynamics. J Geophys Res 102C6:12609–12646
Frankignoul C, Kestenare E (2002) The surface heat flux feedback. Part I: estimates from observations in the Atlantic and the North Pacific. Clim Dyn 19:633–647
Frankignoul C, Kestenare E (2005) Observed atlantic SST anomaly impact on the NAO: an update. J Clim 18(19):4089–4094
Ganachaud A, Wunsch C (2000) Improved estimates of global ocean circulation, heat transport and mixing from hydrographic data. Nature 408:453–456
Ganachaud A, Wunsch C (2003) Large-scale ocean heat and freshwater transports during the World Ocean Circulation Experiment. J Clim 16:696–705
Ganopolski A, Rahmstorf S (2001) Rapid changes of glacial climate simulated in a coupled climate model. Nature 409:153–158
Goelzer H, Mignot J, Levermann A, Rahmstorf S (2006) Tropical versus high latitude freshwater influence on the thermohaline circulation. Clim Dyn 27:715–725
Haarsma RJ, Hazeleger W (2007) Extra-tropical atmospheric response to equatorial Atlantic cold tongue anomalies. J Clim 20, 10:2076–2091
Hakkinen S (2001) Variability in sea surface height: a qualitative measure for the meridional overturning in the North Atlantic. J Geophys Res 106(C7):13837–13848
Hakkinen S, Rhines PB (2004) Surface salinity variability in the northern North Atlantic during recent decades. Science 304(5670):555–559
Haug GH, Konrad AH, Sigman DM, Peterson LC, Röhl U (2001) Southward migration of the intertropical convergence zone through the Holocene. Science 293:1304–1308
Hourdin F, Musat I, Bony S, Braconnot P, Codron F, Dufresne JL, Fairhead L, Filiberti MA, Friedlingstein P, Grandpeix JY, Krinner G, Levan P, Li ZX, Lott F (2006) The LMDZ4 general circulation model: climate performance and sensitivity to parametrized physics with emphasis on tropical convection. Clim Dyn 27(7–8):787–813
Kageyama M, Mignot J, Swingedouw D, Marzin C, Alkama R, Marti O (2009) Glacial sensitivity to different states of the Atlantic Meridional Overturning Circulation: results from the IPSL model. Clim Past Disc 5(2):1055–1107
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:L20708. doi:10.1029/2005GL024233
Krebs U, Timmermann A (2007) Tropical air–sea interactions accelerate the recovery of the Atlantic Meridional Overturning Circulation after a major shutdown. J Clim 20:4940–4956
Latif M (2001) Tropical Pacific/Atlantic ocean interactions at multi-decadal time scales. Geophys Res Lett 28(3):539–542
Latif M, Roeckner E, Mikolajewicz U, Voss R (2000) Tropical stabilization of the thermohaline circulation in a greenhouse warming simulation. J Clim 13:1809–1813
Latif M, B"øning C, Willebrand J, Biastoch A, Dengg J, Keenlyside NS, Schweckendiek U, Madec G (2006) Is the thermohaline circulation changing? J Clim 9(18):4631–4637
Laurian A, Lazar A, Reverdin G, Rodgers K, Terray P (2006) Poleward propagation of spiciness anomalies in the north atlantic ocean. Geophys Res Lett 33:L13603. doi:10.1029/2006GL026155
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
Lherminier P, Mercier H, Gourcuff C, Alvarez M, Bacon S, Kermabon C (2007) Transports across the 2002 Greenland–Portugal Ovide section and comparison with 1997. J Geophys Res 112:C07003 doi:10.1029/2006JC00371616
Lin JL (2007) The double-ITCZ problem in IPCC AR4 coupled GCMs: ocean–atmosphere feedback analysis. J Clim 20:4497–4525
Macdonald AM (1998) The global ocean circulation: a hydrographic estimate and regional analysis. Prog Oceanogr 41:281–382
Madec G, Imbard M (1996) A global ocean mesh to overcome the North Pole singularity. Clim Dyn 12(6):381–388
Madec G, Delecluse P, Imbard M, Levy M (1998) OPA 8. 1, ocean general circulation model reference manual. Notes du pole de modelisation, n. 11 Institut Pierre-Simon Laplace (IPSL), Paris, France
Manabe S, Stouffer RJ (1988) Two stable equilibria of a coupled ocean–atmosphere model. J Clim 1:841–866
Marti O, Braconnot P, Dufresne JL, Bellier J, Benshila R, Bony S, Brockmann P, Cadule P, Caubel A, Codron F, de Noblet N, Denvil S, Fairhead L, Fichefet T, Foujols MA, Friedlingstein P, Goosse H, Grandpeix JY, Guilyardi E, Hourdin F, Krinner G, Lévy C, Madec G, Mignot J, Musat I, Swingedouw D, Talandier C (2009) Key features of the IPSL ocean atmosphere model and its sensitivity to atmospheric resolution. Clim Dyn (in revision)
Merryfield WJ (2006) Changes to ENSO under CO2 doubling in a multimodel ensemble. J Clim 19:4009–4027
Mignot J, Frankignoul C (2005) On the variability of the Atlantic meridional overturning circulation, the North Atlantic Oscillation and the El Niño-Southern Oscillation in the Bergen Climate Model. J Clim 18(13):2361–2375
Mignot J, Ganopolski A, Levermann A (2007) Atlantic subsurface temperatures: response to a shut-down of the overturning circulation and consequences for its recovery. J Clim 20:4884–4898
Msadek R, Frankignoul C (2009) Variability of the meridional overturning circulation and its influence onto the atmosphere in the IPSL climate model. Clim Dyn (accepted). doi:10.1007/s00382-008-0452-0
Otterå OH, Drange H, Bentsen M, Kvamstø NG, Jiang D (2003) The sensitivity of the present-day Atlantic meridional overturning circulation to freshwater forcing. Geophys Res Lett 30(17) (1898)
Peng S, Robinson WA, Li S, Alexander MP (2006) Effects of ekman transport on the NAO response to a tropical Atlantic SST anomaly. J Clim 19:4803–4818
Peterson LC, Haig GH, Hughen KA Röhl U (2000) Rapid changes in the hydrologic cycle of the tropical Atlantic during the last glacial. Science 290:1947–1951
Reverdin G, Kestenare E, Frankignoul C, Delcroix T (2007) Surface salinity in the Atlantic Ocean (30°S–50°N). Prog Oceanog 73:311–340
Saenko OA (2007) Warming of the subpolar atlantic triggered by freshwater discharge at the continental boundary. J Geophys Res 34:L15604
Schmidt MW, Spero HJ, Lea DW (2004) Links between salinity variation in the caribbean and north atlantic thermohaline circulation. Nature 428:160–163
Schneider B, Latif M, Schmittner A (2007) Evaluation of different methods to assess model projections of the future evolution of the atlantic meridional overturning circulation. J Clim 20:2121–2132
Solomon S, Qin D, Manning M, Chen Z, Marquis M, Aveeryt KB, Tignor M, Miller HL et al (eds) (2007) Intergovernmental Panel on Climate Change: Climate Change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, 996 pp
Spence JP, Weaver AJ (2006) The impact of tropical atlantic freshwater fluxes on the north atlantic meridional overturning circulation. J Clim 19:4592–4604
Spence JP, Mike E, Weaver AJ (2008) The sensitivity of the Atlantic meridional overturning circulation to freshwater forcing at eddy-permitting resolutions. J Clim 21:2697–2710
Stouffer RJ, Yin J, Gregory JM, Dixon KW, Spelman MJ, Hurlin W, Weaver AJ, Eby M, Flato GM, Hasumi H, Hu A, Jungclaus JH, Kamenkovich IV, Levermann A, Montoya M, Murakami S, Nawrath S, Oka A, Peltier WR, Robitaille DY, Sokolov AP, Vettoretti G, Weber N (2006) Investigating the causes of the response of the thermohaline circulation to past and future climate changes. J Clim 19:1365–1387
Stouffer RJ, Yin J, Gregory JM, Dixon KW, Spelman MJ, Hurlin W, Weaver AJ, Eby M, Flato GM, Hasumi H, Hu A, Jungclaus JH, Kamenkovich IV, Levermann A, Montoya M, Murakami S, Nawrath S, Oka A, Peltier WR, Robitaille DY, Sokolov AP, Vettoretti G, Weber N (2006) Investigating the causes of the response of the thermohaline circulation to past and future climate changes. J Clim 19:1365–1387
Sutton RT, Hodson DLR (2007) Climate response to basin-scale warming and cooling of the North Atlantic ocean. J Clim 20:891–907. doi:10.1175/JCLI4038.1
Swingedouw D, Braconnot P, Delecluse P, Guilyardi E, Marti O (2007) The impact of global freshwater forcing on the thermohaline circulation: adjustment of north atlantic convection sites in a CGCM. Clim Dyn 28:291–305
Swingedouw D, Mignot J, Braconnot P, Mosquet E, Kageyama M, Alkama R (2009) Impact of freshwater release in the North Atlantic under different climate conditions in an OAGCM. Clim Dyn (accepted)
Talley LD, Reid JL, Robbins PE (2003) Data-based meridional overturning streamfunctions for the global oceans. J Clim 16:3213–3226
Terray L Cassou C (2002) Tropical atlantic sea surface temperature forcing of the quasi-decadal climate variability over the north Atlantic-Europe region. J Clim 15:3170–3187
Thorpe RB, Gregory JM, Johns TC, Wood RA, Mitchell JFB (2001) Mechanisms determining the Atlantic thermohaline circulation response to greenhouse gas forcing in a non-adjusted coupled climate model. J Clim 14:3102–3116
Timmermann A, Okumura Y, An S-I, Clement A, Dong B, Guilyardi E, Hu A, Jungclaus J, Krebs U, Renold M, Stocker TF, Stouffer RJ, Sutton R, Xie S-P, Yin J (2007) The influence of a weakening of the Atlantic meridional overturning circulation on ENSO. J Clim 20:4899–4919
Vellinga M, Wood R (2002) Global climatic impacts of a collapse of the Atlantic thermohaline circulation. Clim Change 54:251–267
Vellinga M, Wood R, Gregory J (2002) Processes governing the recovery of a perturbed thermohaline circulation in HadCM3. J Clim 15(7):764–780
Vellinga M, Wu P (2004) Low latitude freshwater influence on centennial variability of the Atlantic Thermohaline Circulation. J Clim 17(23):4498–4511
Weber NL, Drijfhout SS (2007) Stability of the atlantic meridional overturning circulation in the last glacial climate maximum climate. Geophys Res Lett 34:L22706
Wu L, He F, Liu Z, Li C (2007) Atmospheric teleconnections of tropical Atlantic variability: interhemispheric, tropical–extratropical and cross-basin interactions. J Clim 20
Wunsch C, Heimbach P (2006) Estimated decadal changes in the North Atlantic meridional overturning circulation and heat flux 1993–2004. J Phys Oceanogr 36(11)
Xie S-P, Okumura Y, Miyama T Timmermann A (2008) Influences of Atlantic climate change of the tropical Pacific via the Central American Isthmus. J Clim (in press)
Yang J (1999) A linkage between decadal climate variations in the Labrador Sea and the tropical Atlantic Ocean. Geophys Res Lett 26(8):1023–1026
Zhang R (2007) Anticorrelated multidecadal variations between surface and subsurface tropical North Atlantic. Geophys Res Lett 34(L12713). doi:10.1029/2007GL030225
Acknowledgements
We would like to thank S. Denvil for his help and assistance in running the coupled model. This work was supported in part by the EU Framework 6 program under contract 003903-GOCE (DYNAMITE), the LEFE program and, for C.F., by the Institut Universitaire de France.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Mignot, J., Frankignoul, C. Local and remote impacts of a tropical Atlantic salinity anomaly. Clim Dyn 35, 1133–1147 (2010). https://doi.org/10.1007/s00382-009-0621-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00382-009-0621-9