Climate Dynamics

, Volume 43, Issue 11, pp 2915–2930 | Cite as

Oceanic origin of southeast tropical Atlantic biases

  • Zhao Xu
  • Mingkui Li
  • Christina M. Patricola
  • Ping Chang
Article
First Online:
Received:
Accepted:

Abstract

Most coupled general circulation models suffer from a prominent warm sea surface temperature bias in the southeast tropical Atlantic Ocean off the coast of Africa. The origin of the bias is not understood and remains highly controversial. Previous studies suggest that the origin of the bias stems from systematic errors of atmospheric models in simulating surface heat flux and coastal wind, or poorly simulated coastal upwelling. In this study, we show, using different reanalysis and observational data sets combined with a set of eddy-resolving regional ocean model simulations, that systematic errors in ocean models also make a significant contribution to the bias problem. In particular (1) the strong warm bias at the Angola-Benguela front that is maintained by the local wind and the convergence of Angola and Benguela Currents is caused by an overshooting of the Angola Current in ocean models and (2) the alongshore warm bias to the south of the front is caused by ocean model deficiencies in simulating the sharp thermocline along the Angola coast, which is linked to biases in the equatorial thermocline, and the complex circulation system within the Benguela upwelling zone.

Keywords

Advance Very High Resolution Radiometer Advance Very High Resolution Radiometer Simple Ocean Data Assimilation Warm Bias Climate Forecast System Reanalysis 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in to check access.

References

  1. Bourlès B, Lumpkin R, McPhaden MJ, Hernandez F, Nobre P, Campos E et al (2008) The Pirata program: history, accomplishments, and future directions. Bull Am Meteorol Soc 89:1111–1125CrossRefGoogle Scholar
  2. Breugem WP, Chang P, Jang CJ, Mignot J, Hazeleger W (2008) Barrier layers and tropical Atlantic SST biases in coupled GCMs. Tellus A 60:885–897CrossRefGoogle Scholar
  3. Carton JA, Giese BS (2008) A reanalysis of ocean climate using simple ocean data assimilation (SODA). Mon Weather Rev 136:2999–3017CrossRefGoogle Scholar
  4. Carton JA, Giese BS, Grodsky SA (2005) Sea level rise and the warming of the oceans in the simple ocean data assimilation (SODA) ocean reanalysis. J Geophys Res 110:C09006. doi: 10.1029/2004JC002817 Google Scholar
  5. Chang C-Y, Carton JA, Grodsky SA, Nigam S (2007) Seasonal climate of the tropical Atlantic sector in the NCAR community climate system model 3: error structure and probable causes of errors. J Clim 20:1053–1070CrossRefGoogle Scholar
  6. Chassignet EP, Hurlburt HE, Smedstad OM, Halliwell GR, Hogan PJ, Wallcraft AJ et al (2007) The HYCOM (HYbrid Coordinate Ocean Model) data assimilative system. J Mar Syst 65:60–83CrossRefGoogle Scholar
  7. Colberg F, Reason CJC (2006) A model study of the Angola Benguela Frontal Zone: Sensitivity to atmospheric forcing. Geophys Res Lett 33. doi: 10.1029/2006GL027463
  8. Davey MK, Huddleston M, Sperber KR, Braconnot P, Bryan F, Chen D et al (2002) STOIC: a study of coupled model climatology and variability in tropical ocean regions. Clim Dyn 18:403–420CrossRefGoogle Scholar
  9. DeWitt DG (2005) Diagnosis of the tropical Atlantic near-equatorial SST bias in a directly coupled atmosphere-ocean general circulation model. Geophys Res Lett 32. doi: 10.1029/2004GL021707
  10. Doi T, Tozuka T, Sasaki H, Masumoto Y, Yamagata T (2007) Seasonal and interannual variations of oceanic conditions in the Angola Dome. J Phys Oceanogr 37:2698–2713CrossRefGoogle Scholar
  11. Durski SM, Glenn SM, and Haidvogel DB (2004) Vertical mixing schemes in the coastal ocean: comparison of the level 2.5 Mellor-Yamada scheme with an enhanced version of the K profile parameterization. J Geophys Res Oceans 109. doi: 10.1029/2002JC001702
  12. Florenchie P, Lutjeharms JRE, Reason CJC, Masson S, Rouault M (2003) The source of Benguela Niños in the South Atlantic Ocean. Geophys Res Lett 30(10):1505. doi: 10.1029/2003GL017172 CrossRefGoogle Scholar
  13. Grodsky SA, Carton JA, Nigam S, Okumura YM (2012) Tropical Atlantic biases in CCSM4. J Clim 25:3684–3701CrossRefGoogle Scholar
  14. Huang B, Hu Z–Z, Jha B (2007) Evolution of model systematic errors in the tropical Atlantic basin from coupled climate hindcasts. Clim Dyn 28:661–682CrossRefGoogle Scholar
  15. John HC, Zelck C, Erasmi W (2000) Poleward transport of equatorial fish larvae in the Atlantic Eastern boundary current system. Arch Fish Mar Res 48(1):61–88Google Scholar
  16. Large WG, Danabasoglu G (2006) Attribution and impacts of upper-ocean biases in CCSM3. J Clim 19:2325–2346CrossRefGoogle Scholar
  17. Large WG, Yeager SG (2008) The global climatology of an interannually varying air–sea flux data set. Clim Dyn 33:341–364CrossRefGoogle Scholar
  18. Large WG, Mcwilliams JC, Doney SC (1994) Oceanic vertical mixing: a review and a model with a nonlocal boundary-layer parameterization. Rev Geophys 32:363–403CrossRefGoogle Scholar
  19. Lass HU, Schmidt M, Mohrholz V, Nausch G (2000) Hydrographic and current measurements in the area of the Angola–Benguela front. J Phys Oceanogr 30:2589–2609CrossRefGoogle Scholar
  20. Lemarié F, Kurian J, Shchepetkin A, Molemaker J, Colas F, McWilliams JC (2012) Are there inescapable issues prohibiting the use of terrain-following coordinates in climate models? Ocean Model 42:57–79CrossRefGoogle Scholar
  21. Lübbecke, JF., Böning CW, Keenlyside NS, and Xie S-P (2010), On the connection between Benguela and equatorial Atlantic Niños and the role of the South Atlantic Anticyclone, J Geophys Res, 115. doi: 10.1029/2009JC005964
  22. Mazeika PA (1967) Thermal domes in the eastern tropical Atlantic Ocean. Limnol Oceanogr 12:537–539CrossRefGoogle Scholar
  23. McClain CR, Firestone J (1993) An investigation of Ekman upwelling in the North Atlantic. J Geophys Res 98:12327–12339CrossRefGoogle Scholar
  24. Mohrholz V, Schmidt M, Lutjeharms JRE (2001) The hydrography and dynamics of the Angola-Benguela frontal zone and environment in April 1999. S Afr J Sci 97:199–208Google Scholar
  25. Mohrholz V, Batholomae CH, van der Plas AK, Lass HU (2008) The seasonal variability of the northern Benguela undercurrent and its relation to the oxygen budget on the shelf. Cont Shelf Res 28:424–441CrossRefGoogle Scholar
  26. Patricola CM, Li M, Xu Z, Chang P, Saravanan R, Hsieh J-S (2012) An investigation of tropical Atlantic bias in a high-resolution coupled regional climate model. Clim Dyn 39:2443–2463CrossRefGoogle Scholar
  27. Penven P, Echevin V, Pasapera J, Colas F, and Tam J (2005) Average circulation, seasonal cycle, and mesoscale dynamics of the Peru current system: a modeling approach. J Geophys Res Oceans 110. doi: 10.1029/2005JC002945
  28. Peterson RG, Stramma L (1991) Upper-level circulation in the South Atlantic Ocean. Prog Oceanogr 26:1–73CrossRefGoogle Scholar
  29. Reynolds RW, Smith TM, Liu C, Chelton DB, Casey KS, Schlax MG (2007) Daily high-resolution-blended analyses for sea surface temperature. J Clim 20:5473–5496CrossRefGoogle Scholar
  30. Richter I, Xie S-P (2008) On the origin of equatorial Atlantic biases in coupled general circulation models. Clim Dyn 31:587–598CrossRefGoogle Scholar
  31. Richter I, Xie S-P, Wittenberg AT, Masumoto Y (2011) Tropical Atlantic biases and their relation to surface wind stress and terrestrial precipitation. Clim Dyn 38:985–1001CrossRefGoogle Scholar
  32. Saha S, Moorthi S, Pan H-L, Wu X, Wang J, Nadiga S et al (2010) The NCEP climate forecast system reanalysis. Bull Am Meteorol Soc 91:1015–1057CrossRefGoogle Scholar
  33. Seo H, Jochum M, Murtugudde R, and Miller AJ (2006) Effect of ocean mesoscale variability on the mean state of tropical Atlantic climate. Geophys Res Lett 33. doi: 10.1029/2005GL025651
  34. Shannon LV, Agenbag JJ, Buys MEL (1987) Large- and mesoscale features of the Angola-Benguela front. S Afr J Mar Sci 5:11–34CrossRefGoogle Scholar
  35. Shchepetkin AF, McWilliams JC (2003) A method for computing horizontal pressure-gradient force in an oceanic model with a nonaligned vertical coordinate. J Geophys Res Oceans 108. doi: 10.1029/2001JC001047
  36. Shchepetkin AF, McWilliams JC (2005) The regional oceanic modeling system (ROMS): a split-explicit, free-surface, topography-following-coordinate oceanic model. Ocean Model 9:347–404CrossRefGoogle Scholar
  37. Veitch J, Penven P, Shillington F (2010) Modeling equilibrium dynamics of the Benguela current system. J Phys Oceanogr 40:1942–1964CrossRefGoogle Scholar
  38. Wacongne S, Piton B (1992) The near-surface circulation in the northeastern corner of the South Atlantic ocean. Deep Sea Res Part A Oceanogr Res Pap 39:1273–1298CrossRefGoogle Scholar
  39. Wahl S, Latif M, Park W, Keenlyside N (2009) On the tropical Atlantic SST warm bias in the Kiel climate model. Clim Dyn 36:891–906CrossRefGoogle Scholar
  40. Yamagata T, Iizuka S (1995) Simulation of the tropical thermal domes in the Atlantic—a seasonal cycle. J Phys Oceanogr 25:2129–2140CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Zhao Xu
    • 1
    • 2
  • Mingkui Li
    • 1
    • 2
  • Christina M. Patricola
    • 3
  • Ping Chang
    • 1
    • 2
    • 3
  1. 1.Physical Oceanography LaboratoryOcean University of ChinaQingdaoChina
  2. 2.Department of OceanographyTexas A&M UniversityCollege StationUSA
  3. 3.Department of Atmospheric ScienceTexas A&M UniversityCollege StationUSA

Personalised recommendations