Land–atmosphere–ocean interactions in the southeastern Atlantic: interannual variability

Abstract

Land–atmosphere–ocean interactions in the southeastern South Atlantic and their connections to interannual variability are examined using a regional climate model coupled with an intermediate-level ocean model. In austral summer, zonal displacements of the South Atlantic subtropical high (SASH) can induce variations of mixed-layer currents in the Benguela upwelling region through surface wind stress curl anomalies near the Namibian coast, and an eastward shifted SASH is related to the first Pacific–South American mode. When the SASH is meridionally displaced, mixed layer vertically-integrated Ekman transport anomalies are mainly a response to the change of alongshore surface wind stress. The latitudinal shift of the SASH tends to dampen the anomalous alongshore wind by modulating the land-sea thermal contrast, while opposed by oceanic diffusion. Although the position of the SASH is closely linked to the phase of El Niño–Southern Oscillation (ENSO) and the southern annular mode (SAM) in austral summer, an overall relationship between Benguela upwelling strength and ENSO or SAM is absent. During austral winter, variations of the mixed layer Ekman transport in the Benguela upwelling region are connected to the strength of the SASH through its impact on both coastal wind stress curl and alongshore surface wind stress. Compared with austral summer, low-level cloud cover change plays a more important role. Although wintertime sea surface temperature fluctuations in the equatorial Atlantic are strong and may act to influence variability over the northern Benguela area, the surface heat budget analysis suggests that local air-sea interactions dominate.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15

References

  1. Andrews WRH, Hutchings L (1980) Upwelling in the southern Benguela Current. Prog Oceanogr 9:1–81

    Article  Google Scholar 

  2. Bakun A, Field D, Renondo-Rodriguez A, Weeks SJ (2010) Greenhouse gas, upwelling-favorable winds, and the future of upwelling systems. Glob Chang Biol 16:1213–1228

    Article  Google Scholar 

  3. Balmaseda MA, Vidard A, Anderson DL (2008) ECMWF ocean analysis system: ORA-S3. Mon Wea Rev 136:3018–3034

    Article  Google Scholar 

  4. Behringer DW, Xue Y (2004) Evaluation of the global ocean data assimilation system at NCEP: The Pacific Ocean. In: Proceedings of paper presented at the Eighth Symposium on Integrated Observing and Assimilation System for Atmosphere, Oceans, and Land Surface, American Meteorology of the Society, Seattle, Wash., 11–15 Jan

  5. Breugem W-P, Hazeleger W, Haarsma RJ (2006) Multimodel study of tropical Atlantic variability and change. Geophys Res Lett. https://doi.org/10.1029/2006GL027831

    Google Scholar 

  6. Cabos W, Stein DV, Pinto JG, Fink AH, Koldunov NV, Alvarez F, Izquierdo A, Keenlyside N, Jacob D (2017) The South Atlantic Anticyclone as a key player for the representation of the tropical Atlantic climate in coupled climate model. Clim Dyn 48:4051–4069

    Article  Google Scholar 

  7. Chen F, Dudhia J (2001) Coupling an advanced land-surface/ hydrology model with the Penn State/ NCAR MM5 modeling system. Part I: Model description and implementation. Mon Wea Rev 129:569–585

    Article  Google Scholar 

  8. Chen S-H, Sun W-Y (2002) A one-dimensional time dependent cloud model. J Meteor Soc Japan 80:99–118

    Article  Google Scholar 

  9. Collins WD, Rasch PJ, Boville BA, Hack JJ, et al. (2004) Description of the NCAR Community Atmosphere Model (CAM 3.0), NCAR Technical Note, NCAR/TN-464 + STR, p 226

  10. Cook KH (2000) The South Indian convergence zone and interannual rainfall variability over Southern Africa. J Clim 13:3789–3804

    Article  Google Scholar 

  11. Cook KH (2001) A Southern hemisphere wave response to ENSO with implications for southern Africa precipitation. J Atmos Sci 15:2146–2162

    Article  Google Scholar 

  12. Cook KH, Vizy EK (2012) Impact of climate change on mid-twenty-first century growing seasons in Africa. Clim Dyn 39:2937–2955

    Article  Google Scholar 

  13. Cook KH, Vizy EK (2016) The Congo Basin Walker Circulation: Dynamics and connections to precipitation. Clim Dyn 47:697–717

    Article  Google Scholar 

  14. Cook C, Reason CJC, Hewitson B (2004) Wet and dry spells within particularly wet and dry summers in south African summer rainfall region. Clim Res 26:17–31

    Article  Google Scholar 

  15. Crétat J, Vizy EK, Cook KH (2014) How well are daily intense rainfall events captured by current climate models over Africa? Clim Dyn 42:2691–2711

    Article  Google Scholar 

  16. Crétat J, Vizy EK, Cook KH (2015) The relationship between African easterly waves and daily rainfall over West Africa. Observations and regional climate simulations. Clim Dyn 44:385–404

    Article  Google Scholar 

  17. Davey M, Huddleston M, Sperber K et al (2002) STOIC: a study of coupled model climatology and variability in tropical ocean regions. Clim Dyn 18:403–420

    Article  Google Scholar 

  18. Dee DP, Uppla SM, Simmons AJ, Berrisford P, Poli P, Kobayashi S et al (2011) The ERA-Interim reanalysis: configuration and performance of the data assimilation system. Q J R Meteorol Soc 137:553–597

    Article  Google Scholar 

  19. Dudhia J (1989) Numerical study of convection observed during the winter monsoon experiment using a mesoscale two-dimensional model. J Atmos Sci 46:3077–3107

    Article  Google Scholar 

  20. Enriquez AG, Friehe CA (1995) Effects of wind stress and wind stress curl variability on coastal upwelling. J Phys Oceanogr 25:1651–1671

    Article  Google Scholar 

  21. Fennel W (1999) Theory of the Benguela upwelling system. J Phys Oceanogr 25:177–190

    Article  Google Scholar 

  22. Fennel W, Tucker T, Schimdt M, Mohrholz V (2012) Response of the Benguela upwelling systems to spatial variations in the wind stress. Cont Shelf Res 45:65–77

    Article  Google Scholar 

  23. Florenchie P, Lutjeharms JRE, Reason CJC, Masson S, Rouault M (2003) The source of Bengula Niños in the South Atlantic Ocean. Geophys Res Lett 30: https://doi.org/10.1029/2003GL017172

  24. Florenchie P, Reason C, Lutjeharms J, Rouault M, Roy C, Masson S (2004) Evolution of interannual warm and cold events in the southeast Atlantic Ocean. J Clim 17:2318–2334

    Article  Google Scholar 

  25. Fogt RL, Bromwich DH (2006) Decadal variability of the ENSO teleconnection to the high-latitude South Pacific governed by coupling with the Southern Annular Mode. J Clim 19:979–997

    Article  Google Scholar 

  26. Garzoli SL, Gordon AL (1996) Origins and variability of the Benguela Current. J Geophys Res 101:987–906

    Article  Google Scholar 

  27. Gill AE (1977) Coastally trapped waves in the atmosphere. Quart J Roy Meteor Soc 103:431–440

    Article  Google Scholar 

  28. Gill AE (1980) Some simple solutions for the heat induced tropical circulation. Quart J Roy Meteor Soc 106:447–462

    Article  Google Scholar 

  29. Gong T, Feldstein SB, Luo D (2010) The impact of ENSO on wave breaking and southern annular mode events. J Atmos Sci 67:2854–2870

    Article  Google Scholar 

  30. Hagos SM, Cook KH (2009) Development of a coupled regional model and its application to the study of interactions between the West African monsoon and the eastern tropical Atlantic Ocean. J Clim 22:2591–2604

    Article  Google Scholar 

  31. Hansingo K, Reason CJC (2009) Modelling the atmospheric response over southern Africa to SST forcing in the southeast tropical Atlantic and southwest subtropical Indian Oceans. Int J Climatol 29:1001–1012

    Article  Google Scholar 

  32. Hong S-Y, Noh Y, Dudhia J (2006) A new vertical diffusion package with an explicit treatment of entrainment processes. Mon Wea Rev 134:2318–2341

    Article  Google Scholar 

  33. Huang B, Hu Z-Z (2007) Cloud-SST feedback in southeastern tropical Atlantic anomalous events. J Geophys Res. https://doi.org/10.1029/2006JC003626

    Google Scholar 

  34. Hutchings L, van der Lingen CD, Shannon LJ, Crawford RJM, Verheye HMS, Bartholomae CH et al (2009) The Benguela Current: An ecosystem of four components. Prog Oceanogr 83:15–32

    Article  Google Scholar 

  35. Jarre A, Hutchings L, Kirkman SP, Kreiner A, Tchipalanga P, Kainge P et al (2015) Synthesis: climate effects on biodiversity, abundance and distribution of marine organisms in the Benguela. Fish Oceanogr 24:122–149

    Article  Google Scholar 

  36. Kain JS (2004) The Kain-Fritsch convective parameterization: An update. J Appl Meteor 43:170–181

    Article  Google Scholar 

  37. Klein SA, Hartmann DL (1993) The seasonal cycle of low stratiform clouds. J Clim 6:1587–1606

    Article  Google Scholar 

  38. Lübbecke JF, 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. https://doi.org/10.1029/2009JC00596

    Google Scholar 

  39. Lutjeharms JRE, Meeuwis JM (1987) The extent and variability of South-East Atlantic upwelling. S Afr J Mar Sci 5:51–62

    Article  Google Scholar 

  40. Marshall GJ (2003) Trends in the Southern Annular Mode from observations and reanalyses. J Clim 16:4134–4143

    Article  Google Scholar 

  41. Mlawer EJ, Taubman SJ, Brown PD, Iacono MJ, Clough SA (1997) Radiative transfer for inhomogeneous atmosphere: RRTM, a validated correlated-k model for the longwave. J Geophys Res 102:16663–16682

    Article  Google Scholar 

  42. Mo KC, Paegle JN (2001) The Pacific-South American modes and their downstream effects. Int J Climatol 21:1211–1229

    Article  Google Scholar 

  43. Munday C, Washington R (2017) Circulation controls on southern African precipitation in coupled models: the role of the Angola Low. J Geophys Res 122:861–877

    Article  Google Scholar 

  44. Nelson G, Hutchings L (1983) The Benguela upwelling area. Prog Oceanog 12:333–356

    Article  Google Scholar 

  45. Nicholson SE (2010) A low-level jet along the Benguela Coast, an integral part of the Benguela current ecosystem. Clim Change 99:613–624

    Article  Google Scholar 

  46. Nicholson SE, Entekhabi D (1987) Rainfall variability in equatorial and Southern Africa: relationships with sea-surface temperatures along the southwestern coast of Africa. J Clim Appl Meteorol 26:561–578

    Article  Google Scholar 

  47. Ohishi S, Sugimoto S, Hanawa K (2015) Zonal movement of the Mascarene High in austral summer. Clim Dyn 45:1739–1745

    Article  Google Scholar 

  48. Patricola CM, Chang P (2016) Structure and dynamics of the Benguela low-level coastal jet. Clim Dyn. https://doi.org/10.1007/s00382-016-3479-7

    Google Scholar 

  49. Patricola CM, Li M, Xu Z, Chang P, Saravanan R, Hsieh J (2012) An invesitgation of tropical Atlantic bias in a high-resolution coupled regional climate model. Clim Dyn 39:2443–2463

    Article  Google Scholar 

  50. Polo I, Lazar A, Rodriguez-Fonseca B, Arnault S (2008a) Oceanic Kelvin waves and tropical Atlantic intraseasonal variability: 1. Kelvin wave characterization. J Geophys Res. https://doi.org/10.1029/2007JC004495

    Google Scholar 

  51. Polo I, Rodríguez-Fonseca B, Losada T, García-Serrano J (2008b) Tropical Atlantic Variability Modes (1979–2002). Part I: time-evolving SST modes related to West African rainfall. J Clim 21:6457–6475

    Article  Google Scholar 

  52. Ranjha R, Svensson G, Tjernström M, Semedo A (2013) Global distribution and seasonal variability of coastal low-level jets derived from ERA-Interim reanalysis. Tellus A 65:20412

    Article  Google Scholar 

  53. Richter I, Xie S (2008) On the origin of equatorial Atlantic biases in coupled general circulation models. Climate Dyn 31:587–598

    Article  Google Scholar 

  54. Richter I, Mechoso CR, Robertson AW (2008) What determines the position and intensity of the South Atlantic Anticyclone in austral winter? An AGCM Study. J Clim 21:214–229

    Article  Google Scholar 

  55. Richter I, Behera SK, Masumoto Y, Taguchi B, Komori N, Yamagata T (2010) On the triggering of Benguela Niños: Remote equatorial versus local influences. Geophys Res Lett. https://doi.org/10.1029/2010GL044461

    Google Scholar 

  56. Richter I, Xie S, Wittenberg AT, Masumoto Y (2012) Tropical Atlantic biases and their relation to surface wind stress and terrestrial precipitation. Clim Dyn 38:985–1001

    Article  Google Scholar 

  57. Rodwell MJ, Hoskins BJ (2001) Subtropical anticyclones and summer monsoons. J Clim 14:3192–3211

    Article  Google Scholar 

  58. Rouault M, Illig S, Bartholomae C, Reason CJC, Bentamy A (2007) Propagation and origin of warm anomalies in the Angola Benguela upwelling system in 2001. J Mar Syst 68:473–488

    Article  Google Scholar 

  59. Shannon LV (1985) The Benguela ecosystem Part I. Evolution of the Benguela, physical features and processes. Oceanogr Mar Biol Ann Rev 23:105–182

    Google Scholar 

  60. Shannon LV, Boyd AJ, Bundrit GB, Taunton-Clark J (1986) On the existence of an El Niño-type phenomenon in the Benguela system. J Mar Sci 44:495–520

    Google Scholar 

  61. Skamarock W, Klemp J, Dudhia J, Gill D, Barker D (2008) A description of the Advanced Research WRF version 3. Tech. rep., NCAR/TN-4751STR, p. 113

  62. Small RJ, Curchitser E, Hedstrom K, Kauffman B, Large WG (2015) The Benguela upwelling system: quantifying the sensitivity to resolution and coastal wind representation in a global climate model. J Clim 28:9409–9432

    Article  Google Scholar 

  63. Sterl A, Hazeleger W (2003) Coupled variability and air-sea interaction in the South Atlantic Ocean. Clim Dyn 21:559–571

    Article  Google Scholar 

  64. Stramma L, Peterson RG (1990) The South Atlantic Current. J Phys Oceanogr 20:846–859

    Article  Google Scholar 

  65. Sun X, Cook KH, Vizy EK (2017) The South Atlantic Subtropical High: climatology and interannual variability. J Clim 30:3279–3296

    Article  Google Scholar 

  66. Taljaard JJ, Schmitt W, Van Loon H (1961) Frontal analysis with application to the Southern Hemisphere. Notos 10:25–58

    Google Scholar 

  67. Thompson DWJ, Wallace JM (2000) Annular modes in the extratropical circulation. part I: month-to-month variability. J Clim 13:1000–1016

    Article  Google Scholar 

  68. Toniazzo T, Woolnough S (2013) Development of warm SST errors in the southern tropical Atlantic in CMIP5 decadal hindcasts. Clim Dyn 43:2889–2913

    Article  Google Scholar 

  69. Trzaska S, Robertson AW, Farrara JD, Mechoso CR (2007) South Atlantic variability arising from air–sea coupling: local mechanisms and tropical–subtropical interactions. J Clim 20:3345–3365

    Article  Google Scholar 

  70. Venegas SA, Mysak LA, Straub DN (1997) Atmosphere–ocean coupled variability in the South Atlantic. J Clim 10:2904–2920

    Article  Google Scholar 

  71. Vigaud N, Richard Y, Rouault M, Fauchereau N (2009) Moisture transport between the South Atlantic Ocean and Southern Africa: relationships with summer rainfall and associated dynamics. Clim Dyn 32:113–123

    Article  Google Scholar 

  72. Vizy EK, Cook KH (2001) Mechanisms by which the Gulf of Guinea and eastern North Atlantic sea surface temperature anomalies can influence African rainfall. J Clim 14:795–821

    Article  Google Scholar 

  73. Vizy EK, Cook KH (2002) Development and application of a mesoscale climate model for the tropics: influence of sea surface temperature anomalies on the West African monsoon. J Geophys Res. https://doi.org/10.1029/2001JD000686

    Google Scholar 

  74. Vizy EK, Cook KH (2012) Mid-twenty-first-century changes in extreme events over northern and tropical Africa. J Clim 25:5748–5767

    Article  Google Scholar 

  75. Vizy EK, Cook KH (2014) Capturing the Atlantic cold tongue and coastal upwelling in an intermediate-level ocean model coupled to a regional climate model. Clim Dyn 42:345–366

    Article  Google Scholar 

  76. Vizy EK, Cook KH, Crétat J, Neupane N (2013) Projections of a wetter Sahel in the twenty-first century from global and regional models. J Clim 26:4664–4687

    Article  Google Scholar 

  77. Vizy EK, Cook KH, Chimphamba J, McCusker B (2015) Projected changes in Malawi’s growing season. Clim Dyn 45:1673–1698

    Article  Google Scholar 

  78. Vizy EK, Cook KH, Sun X (2018) Decadal change of the south Atlantic ocean Angola-Benguela frontal zone since 1980. Clim Dyn. https://doi.org/10.1007/s00382-018-4077-7

    Google Scholar 

  79. Weisman ML, Skamarock WC, Klemp JB (1997) The resolution dependence of explicitly modeled convective systems. Mon Weather Rev 125:527–548

    Article  Google Scholar 

  80. Wolter K, Timlin M (2011) El Niño/Southern oscillation behaviour since 1871 as diagnosed in an extended multivariate enso index (MEI.ext). Int J Climatol 31:1074–1087

    Article  Google Scholar 

  81. Xie P, Arkin PA (1997) Global precipitation: a 17-year monthly analysis based on gauge observations, satellite estimates, and numerical model outputs. Bull Am Meteorol Soc 78:2539–2558

    Article  Google Scholar 

  82. Xu Z, Chang P, Richter I, Kim W, Tang G (2014) Diagnosing southeast tropical Atlantic SST and ocean circulation biases in the CMIP5 ensemble. Clim Dyn 43:3123–3145

    Article  Google Scholar 

  83. Zebiak SE (1993) Air-sea interaction in the equatorial Atlantic region. J Clim 6:1567–1586

    Article  Google Scholar 

Download references

Acknowledgements

This research was supported by award NNX13AQ76G from NASA’s Physical Oceanography Program. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of NASA. We thank the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing high performance computing and data storage resources. The ERA-Interim product was obtained from the Computational and Information System Laboratory (CISL) at the National Center for Atmospheric Research (NCAR).

Author information

Affiliations

Authors

Corresponding author

Correspondence to Kerry H. Cook.

Electronic supplementary material

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Sun, X., Vizy, E.K. & Cook, K.H. Land–atmosphere–ocean interactions in the southeastern Atlantic: interannual variability. Clim Dyn 52, 539–561 (2019). https://doi.org/10.1007/s00382-018-4155-x

Download citation

Keywords

  • Ocean Atmosphere Land Interactions
  • Surface Wind Stress Curl
  • El Niño Southern Oscillation (ENSO)
  • Equatorial Atlantic
  • Ocean Mixed Layer Temperature