Climatic Change

, Volume 98, Issue 3–4, pp 331–357 | Cite as

CMIP3 projected changes in the annual cycle of the South American Monsoon

  • Anji Seth
  • Maisa Rojas
  • Sara A. Rauscher


Nine models from the Coupled Model Intercomparison Project version 3 dataset are employed to examine projected changes in the South American Monsoon System annual cycle by comparing the 20th Century and SRES A2 scenarios. The following hypotheses are examined: (1) the warm season climate responses in the Southeast, Continental South Atlantic Convergence Zone (CSACZ) and Monsoon regions are related by regional circulation and moisture transport changes which, in turn, must be consistent with robust large-scale changes in the climate system, and (2) an increased threshold for convection in a warmer world may affect the timing of warm season rains. The present analysis reaffirms that the Southeast region is likely to experience increased precipitation through the warm season. Additional results exhibit more uncertainty due to large inter-model variance and disagreement in the A2 scenarios. Nevertheless several statistically significant results are found. In the Monsoon and to a lesser extent in the CSACZ region, the multi-model median suggests reduced precipitation during spring (Sep–Nov). These continental precipitation changes are accompanied by a southward shift of the maximum precipitation in the South Atlantic Convergence Zone. Changes in circulation include a poleward displaced South Atlantic Anticyclone (SAAC) and enhanced moisture transport associated with a strengthened northerly low level flow east of the Andes during spring. Moisture transport divergence calculations indicate unchanged divergence in the Monsoon region during spring and increased convergence in the Southeast throughout the warm season. The circulation and moisture transport changes suggest the increased precipitation in the Southeast during spring may be related to changes in the SALLJ and SAAC, which both enhance moisture transport to the Southeast. The seasonally dry Monsoon region is further affected by an increased threshold for convection in the warmer, more humid and stable climate of the 21st century, which combined with the circulation changes may weaken the onset of the rainy season. Although there is substantial variability among the models, and the results are represented by small changes compared with the multi-model variance, their statistical significance combined with their consistency with expected robust large scale changes provides a measure of confidence in otherwise tentative results. Further testing of the relationships presented here will be required to fully understand projected changes in the South American Monsoon.


Moisture Transport Monsoon Region South Atlantic Convergence Zone South American Monsoon South American Monsoon System 
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.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Allen MR, Stott PA, Mitchell JFB, Schnur R, Delworth TL (2000) Quantifying the uncertainty in forecasts of anthropogenic climate change. Nature 407:617–620. doi: 10.1038/35036559 CrossRefGoogle Scholar
  2. Berbery EH, Barros VR (2002) The hydrologic cycle of the La Plata basin in South America. J Hydrometeorol 3:630–645CrossRefGoogle Scholar
  3. Carvalho LMV, Jones C, Liebmann B (2002) Extreme precipitation in southeastern South America and large scale convective patterns in the South Atlantic convergence zone. J Climate 15:2377–2394CrossRefGoogle Scholar
  4. Carvalho LMV, Jones C, Liebmann B (2004) The South Atlantic Convergence Zone: intensity, form, persistence, and relationships with intraseasonal to interannual activity and extreme rainfall. J Climate 17:88–108CrossRefGoogle Scholar
  5. Christensen JH, Hewitson B, Busuioc A, Chen A, Gao X, Held I, Jones R, Kolli RK, Kwon WT, Laprise R, Rueda VM, Mearns L, Menéndez CG, Räisänen J, Rinke A, Sarr A, Whetton P (2007) Regional climate projections. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt K, Tignor M, Miller H (eds) Climate change 2007: the physical science basis. Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change, chap. 11. Cambridge University Press, New York, pp 235–336Google Scholar
  6. Cook KH, Vizy EK, Launer ZS, Patricola CM (2008) Springtime intensification of the great plains low-level jet and midwest precipitation in GCM simulations of the 21st century. J Climate. doi: 10.1175/2008JCLI2355.1 Google Scholar
  7. Diaz A, Aceituno P (2003) Atmospheric circulation anomalies during episodes of enhanced and reduced convective cloudiness over Uruguay. J Climate 16:3171–3185CrossRefGoogle Scholar
  8. Gan MA, Kousky VE, Ropelewski CF (2004) The South American Monsoon circulation and its relationship to rainfall over West-Central Brazil. J Climate 17:47–66CrossRefGoogle Scholar
  9. Gan MA, Rao VB, Moscati CL (2006) South American Monsoon indices. Atmos Sci Lett 6:219–223. doi: 10.1002/asl.119 CrossRefGoogle Scholar
  10. Giorgi F, Bi X (2005) Updated regional precipitation and temperature changes for the 21st century from ensembles of AOGCM simulations. Geophys Res Lett 33:l21715CrossRefGoogle Scholar
  11. Held IM, Soden BJ (2006) Robust responses of the hydrological cycle to global warming. J Climate 19:5686–5699CrossRefGoogle Scholar
  12. Herdies DL, da Silva A, Silva Dias MAF, Nieto Ferreira R (2002) Moisture budget of the bimodal pattern of the summer circulation over South America. J Geophys Res 107(D20):8075. doi: 10.1029/2001JD000997 CrossRefGoogle Scholar
  13. Kalnay E, Kanamitsu M, Kistler R, Collins W, Deaven D, Gandin L, Iredell M, Saha S, White G, Woollen J, Zhu Y, Leetmaa A, Reynolds B, Chelliah M, Ebisuzaki W, Higgins W, Janowiak J, Mo KC, Ropelewski C, Wang J, Jenne R, Joseph D (1996) The NCEP/NCAR 40-year reanalysis project. Bull Am Meteorol Soc 77:437–472CrossRefGoogle Scholar
  14. Kharin VV, Zwiers FW, Zhang X, Hegerl GC (2007) Changes in temperature and precipitation extremes in the IPCC ensemble of global coupled model simulations. J Climate 20:1419–1444CrossRefGoogle Scholar
  15. Kodama YM (1992) Large-scale common features of subtropical precipitation zones (the Baiu frontal zone, the SPCZ, and the SACZ). Part I: characteristics of the subtropical frontal zones. J Meteorol Soc Jpn 70:813–836Google Scholar
  16. Kodama YM (1993) Large-scale common features of subtropical precipitation zones (the Baiu frontal zone, the SPCZ, and the SACZ). Part II: conditions of the circulation for generating the STCZs. J Meteorol Soc Jpn 71:581–610Google Scholar
  17. Kousky VE, Kagano MT, Cavalcanti IFA (1984) A review of the Southern Oscillation: oceanic-atmospheric circulation changes and related rainfall anomalies. Tellus Series A 36:490CrossRefGoogle Scholar
  18. Li W, Fu R, Dickinson RE (2006) Rainfall and its seasonality over the Amazon in the 21st century as assessed by the coupled models for the IPCC AR4. J Geophys Res 111:D02111. doi: 10.1029/2005JD006355 CrossRefGoogle Scholar
  19. Liebmann B, Vera CS, Carvalho LMV, Camilloni IA, Hoerling MP, Allured D, Barros VR, Báez J, Bidegain M (2004) An observed trend in Central South American precipitation. J Climate 17:4357–4367CrossRefGoogle Scholar
  20. Lintner BR, Neelin JD (2006) A prototype for convective margin shifts. Geophys Res Lett 34. doi: 10.1029/2006GL027305 Google Scholar
  21. Marengo J (1992) Interannual variability of surface climate in the Amazon basin. Int J Climatol 12:853–863CrossRefGoogle Scholar
  22. Marengo JA, Douglas M, Silva Dias P (2002) The South American low level jet East of the Andes during LBA-TRMM and WET AMC campaign of January–April 1999. J Geophys Res 107(47):1–11Google Scholar
  23. Marengo JA, Soares WR, Saulo C, Nicolini M (2004) Climatology of the low level jet East of the Andes as derived from NCEP-NCAR reanalyses: characteristics of temporal variability. J Climate 17(12):2261–2280CrossRefGoogle Scholar
  24. Meehl GA, Covey C, Delworth T, Mojib L, McAvaney B, Mitchell JFB, Stouffer RJ, Taylor KE (2007) The WCRP CMIP3 multimodel dataset: a new era in climate change research. Bull Am Meteorol Soc 88:1383–1394CrossRefGoogle Scholar
  25. Neelin JD, Chou C, Su H (2003) Tropical drought regions in global warming and El Niño teleconnections. Geophys Res Lett 30(24):2275. doi: 10.1029/2003GL018625 CrossRefGoogle Scholar
  26. Nogués-Paegle J, Mo KC (1997) Alternating wet and dry conditions over South America during summer. Mon Weather Rev 125:279–291CrossRefGoogle Scholar
  27. Paegle J (1998) A comparative review of South American low-level jets. Meteorologica 23:73–81Google Scholar
  28. Rauscher SA, Giorgi F, Diffenbaugh NS, Seth A (2008) Extension and intesification of the Meso-American mid-summer drought in the twenty-first century. Clim Dyn 31:551–571. doi: 10.1007/s00382-007-0359-1 CrossRefGoogle Scholar
  29. Ropelewski CF, Halpert MS (1987) Global and regional scale precipitation patterns associated with the El Niño Southern Oscillation. Mon Weather Rev 115:1606–1626CrossRefGoogle Scholar
  30. Solomon S, Qin D (2007) Climate change 2007: the physical science basis. In: Working group I report to the fourth assessment of the Intergovernmental Panel on Climate Change (IPCC). Cambridge University Press, CambridgeGoogle Scholar
  31. Vecchi GA, Soden BJ (2007) Global warming and the weakening of the tropical circulation. J Climate 20:4316–4340CrossRefGoogle Scholar
  32. Vera C, Baez J, Douglas M, Emmanuel CB, Marengo J, Meitin J, Nicolini M, Nogues-Paegle J, Paegle J, Penalba O, Salio P, Saulo C, Silva Dias MA, Silva Dias P, Zipser E (2006a) The South American low-level jet experiment. Bull Am Meteorol Soc 87:63–77CrossRefGoogle Scholar
  33. Vera C, Higgins W, Amador J, Ambrizzi T, Garreaud R, Gochis D, Gutzler D, Lettenmaier D, Marengo J, Nogues-Paegle J, Silva Dias P, Zhang C (2006b) Toward a unified view of the American monsoon systems. J Climate 19:4977–5000CrossRefGoogle Scholar
  34. Vera C, Silvestri G, Liebmann B, Gonzalez P (2006c) Climate change scenarios for seasonal precipitation in South America from IPCC-AR4 models. Geophys Res Lett 33. doi: 10.1029/2006GL025759 Google Scholar
  35. Virji H (1981) A preliminary study of summertime tropospheric circulation patterns over South America estimated from cloud winds. Mon Weather Rev 109:599–610CrossRefGoogle Scholar
  36. Wilks DS (2005) Statistical methods in the atmospheric sciences, vol 91, 2nd edn. Academic, LondonGoogle Scholar
  37. Xie P, Arkin P (1996) Analysis of global monthly precipitation using gauge observation, satellite estimates and numerical model predictions. J Climate 9:840–858CrossRefGoogle Scholar
  38. Yin JH (2005) A consistent poleward shift of the storm tracks in simulations of 21st century climate. Geophys Res Lett 32:L18701. doi: 10.1029/2005GL023684 CrossRefGoogle Scholar
  39. Zhou J, Lau KM (1998) Does a monsoon climate exist over South America? J Climate 11:1020–1040CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  1. 1.Department of GeographyUniversity of ConnecticutStorrsUSA
  2. 2.Universidad de ChileSantiagoChile
  3. 3.Earth System Physics SectionThe Abdus Salam International Centre for Theoretical PhysicsTriesteItaly

Personalised recommendations