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Climate Dynamics

, Volume 38, Issue 5–6, pp 985–1001 | Cite as

Tropical Atlantic biases and their relation to surface wind stress and terrestrial precipitation

  • Ingo RichterEmail author
  • Shang-Ping Xie
  • Andrew T. Wittenberg
  • Yukio Masumoto
Article

Abstract

Most coupled general circulation models (GCMs) perform poorly in the tropical Atlantic in terms of climatological seasonal cycle and interannual variability. The reasons for this poor performance are investigated in a suite of sensitivity experiments with the Geophysical Fluid Dynamics Laboratory (GFDL) coupled GCM. The experiments show that a significant portion of the equatorial SST biases in the model is due to weaker than observed equatorial easterlies during boreal spring. Due to these weak easterlies, the tilt of the equatorial thermocline is reduced, with shoaling in the west and deepening in the east. The erroneously deep thermocline in the east prevents cold tongue formation in the following season despite vigorous upwelling, thus inhibiting the Bjerknes feedback. It is further shown that the surface wind errors are due, in part, to deficient precipitation over equatorial South America and excessive precipitation over equatorial Africa, which already exist in the uncoupled atmospheric GCM. Additional tests indicate that the precipitation biases are highly sensitive to land surface conditions such as albedo and soil moisture. This suggests that improving the representation of land surface processes in GCMs offers a way of improving their performance in the tropical Atlantic. The weaker than observed equatorial easterlies also contribute remotely, via equatorial and coastal Kelvin waves, to the severe warm SST biases along the southwest African coast. However, the strength of the subtropical anticyclone and along-shore winds also play an important role.

Keywords

Tropical Atlantic GCM biases Coupled modeling Equatorial Atlantic Southeast Atlantic Surface winds Terrestrial precipitaiton 

Notes

Acknowledgments

The authors would like to thank Dr. Swadhin Behera for his helpful comments. Thanks to the two anonymous reviewers for their helpful comments. This work was supported by the NOAA Climate Variability Program, NASA, and JAMSTEC. IPRC/SOEST publication number #765/8109.

References

  1. Abramowitz G, Pitman A, Gupta H, Kowalczyk E, Wang Y (2007) Systematic bias in land surface models. J Hydrometeor 8:989–1001CrossRefGoogle Scholar
  2. Abramowitz G, Leuning R, Clark M, Pitman A (2008) Evaluating the performance of land surface models. J Clim 21:5468–5481CrossRefGoogle Scholar
  3. Breugem WP, Hazeleger W, Haarsma RJ (2006) Multimodel study of tropical Atlantic variability and change. Geophys Res Lett 33. doi: 10.1029/2006GL027831
  4. Breugem WP, Chang P, Jang CJ, Mignot J, Hazeleger W (2008) Barrier layers and tropical Atlantic SST biases in coupled GCMs. Tellus 60A:885–897Google Scholar
  5. Chang P et al (2006) Climate fluctuations of tropical coupled system—the role of ocean dynamics. J Clim 19:5122–5174CrossRefGoogle Scholar
  6. Chang CY, 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
  7. Chang CY, Nigam S, Carton JA (2008) Origin of the springtime westerly bias in equatorial Atlantic surface winds in the Community Atmosphere Model version 3 (CAM3) simulation. J Clim 21:4766–4778CrossRefGoogle Scholar
  8. Davey MK et al (2002) STOIC: a study of coupled model climatology and variability in tropical ocean regions. Clim Dyn 18:403–420CrossRefGoogle Scholar
  9. Delworth TL et al (2006) GFDL’s CM2 global coupled climate models. Part I: formulation and simulation characteristics. J Climate 19:643–674CrossRefGoogle Scholar
  10. Dirmeyer PA, Koster RD, Guo Z (2006) Do global models properly represent the feed-back between land and atmosphere? J Hydrometeor 7:1177–1198CrossRefGoogle Scholar
  11. 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. doi: 10.1029/2003GL017,172
  12. GFDL Global Atmospheric Model Development Team (2004) The new GFDL global atmosphere and land model AM2/LM2: evaluation with prescribed SST simulations. J Clim 17:4641–4673CrossRefGoogle Scholar
  13. Hu Z-Z, Huang B, Hou Y-T, Wang W, Yang F, Stan C, Schneider EK (2010) Sensitivity of tropical climate to low-level clouds in the NCEP climate forecast system. Clim Dyn doi  10.1007/s00382-010-0797-z
  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. Keenlyside NS, Latif M (2007) Understanding equatorial Atlantic interannual variability. J Clim 20:131–142CrossRefGoogle Scholar
  16. Kousky VE (1980) Diurnal rainfall variation in northeast Brazil. Mon Weather Rev 108:488–498CrossRefGoogle Scholar
  17. Large WG, Danabasoglu G (2006) Attribution and impacts of upper-ocean biases in CCSM3. J Clim 19:2325–2346CrossRefGoogle Scholar
  18. Laurent H, Machado LAT, Morales CA, Durieux L (2002) Characteristics of the Amazonian mesoscale convective systems observed from satellite and radar during the WETAMC/LBA experiment. J Geophys Res 107. doi: 10.1029/2001JD000337
  19. Locarnini RA, Mishonov AV, Antonov JI, Boyer TP, Garcia HE (2006) World Ocean Atlas 2005, vol 1: temperature. In: Levitus S (ed) NOAA Atlas NESDIS 61. U.S. Government Printing Office, Washington, DC, p 182Google Scholar
  20. Lübbecke JF, Böning CW, Keenlyside NS, Xie S-P (2010) On the connection between Benguela and equatorial Nñios and the role of the South Atlantic anticyclone. J Geophys Res 115. doi: 10.1029/2009JC005964
  21. Lumpkin R, Garzoli S (2005) Near-surface circulation in the Tropical Atlantic Ocean Deep Sea Res I 52:495–518. doi: 10.1016/j.dsr.2004.09.001
  22. Misra V, Marx L, Brunke M, Zeng X (2008) The equatorial Pacific cold tongue bias in a coupled climate model. J Clim 21:5852–5869CrossRefGoogle Scholar
  23. Moore D, Hisard P, McCreary J, Merle J, O’Brien J, Picaut J, Verstraete J-M, Wunsch C (1978) Equatorial adjustment in the eastern Atlantic. Geophys Res Lett 5:637–640CrossRefGoogle Scholar
  24. Pinty B, Lavergne T, Dickinson RE, Widlowski J-L, Gobron N, Verstraete MM (2006) Simplifying the interaction of land surfaces with radiation for relating remote sensing products to climate models. J Geophys Res 111. doi: 10.1029/2005JD005952
  25. Polo I, Rodríguez-Fonseca B, Losada T, García-Serrano J (2008) Tropical Atlantic variability modes (1979–2002). Part I: time-evolving SST modes related to West African rainfall. J Clim 21:6457–6475CrossRefGoogle Scholar
  26. Repelli CA, Nobre P (2004) Statistical prediction of sea surface temperature over the tropical Atlantic. Int J Climatol 24:45–55CrossRefGoogle Scholar
  27. Richter I, Xie S-P (2008) On the origin of equatorial Atlantic biases in coupled general circulation models. Clim Dyn 31:587–598CrossRefGoogle Scholar
  28. Richter I, Behera SK, Masumoto Y, Taguchi B, Komori N, Yamagata T (2010) On the triggering of Benguela Niños—remote equatorial vs. local influences. Geophys Res Lett 37. doi: 10.1029/2010GL044461
  29. 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 68:473–488CrossRefGoogle Scholar
  30. Stockdale TN, Balmaseda MA, Vidard A (2006) Tropical Atlantic SST prediction with coupled ocean–atmosphere GCMs. J Clim 19:6047–6061CrossRefGoogle Scholar
  31. Wahl S, Latif M, Park W, Keenlyside N (2009) On the tropical Atlantic SST warm bias in the Kiel Climate Model. Clim Dyn. doi: 10.1007/s00382-009-0690-9
  32. Wang D, Wang G, Agnostou EN (2005) Use of satellite-based precipitation observation in improving the parameterization of canopy hydrological processes in land surface models. J Hydrometeor 6:745–763CrossRefGoogle Scholar
  33. Wittenberg AT, Rosati A, Lau N-C, Ploshay JJ (2006) GFDL’s CM2 global coupled climate models. Part III: Tropical Pacific climate and ENSO. J Clim 19:698–722CrossRefGoogle Scholar
  34. Xie S-P, Carton JA (2004) Tropical Atlantic variability: patterns, mechanisms, and impacts. In: Earth climate: the ocean–atmosphere interaction geophysical monograph, vol 147. AGU, Washington, DC, pp 121–142Google Scholar
  35. Yamagata T, Iizuka S (1995) Simulation of the tropical thermal domes in the Atlantic: a seasonal cycle. J Phys Oceanogr 25:2129–2140CrossRefGoogle Scholar
  36. Yuan J, Houze A Jr (2010) Global variability of mesoscale convective system anvil structure from A-train satellite data. J Clim 23:5864–5888CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Ingo Richter
    • 1
    • 2
    Email author
  • Shang-Ping Xie
    • 2
    • 3
  • Andrew T. Wittenberg
    • 4
  • Yukio Masumoto
    • 5
  1. 1.Research Institute for Global Change, JAMSTECYokohamaJapan
  2. 2.International Pacific Research CenterUniversity of Hawaii at ManoaHonoluluUSA
  3. 3.Department of MeteorologyUniversity of Hawaii at ManoaHonoluluUSA
  4. 4.NOAA/Geophysical Fluid Dynamics LaboratoryPrincetonUSA
  5. 5.Research Institute for Global Change, JAMSTECYokohamaJapan

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