Abstract
While numerous detailed studies have been conducted of the annual cycle of convection over other regions (e.g., the Asian summer monsoon and the West African summer monsoon regions), the annual cycle and its modulation in the tropical South American region has received attention only relatively recently. Most of the annual total rainfall observed over tropical South America occurs during the austral summer and autumn months. The large-scale meteorological systems that modulate rainfall during these periods are linked to the strength and movement of large-scale climatological features—in particular, the Intertropical Convergence Zone (ITCZ) and the South Atlantic Convergence Zone (SACZ). It is well known that the anomalous patterns related to the El Niño/Southern Oscillation (ENSO) influence the ITCZ and SACZ patterns, with strong interan-nual and seasonal variations over tropical and subtropical South America.
The goal of this chapter is to analyze the influence of ENSO events on the regional Hadley and Walker cells and their respective impacts on South American seasonal rainfall. As is well documented, ENSO events influence regional precipitation patterns over South America, with the strongest influences in the Amazon/Northeast Brazil and southern South America.
Basically, two separate responses can be composited for each phase of the ENSO cycle. El Niño (La Niña) Composite 1 is the canonical ENSO warm (cold) event with well-known impacts on large-scale atmospheric circulation and regional precipitation patterns over
South America, indicating that the central-eastern Pacific sea surface temperature anomaly (SSTa) is the dominating feature in this case. On the other hand, the El Niño and La Niña Composite 2 analyses characterize the influence of the intertropical Atlantic SST gradients as being significant in modulating the influence of ENSO by intensifying the SACZ and ITCZ in some cases. For these latter composites, evidence of a completely reversed atmospheric circulation and regional precipitation patterns is found during the summer and autumn seasons. The analysis demonstrates that interaction of ENSO events with the South American monsoon produces changes in the time and space evolution of convection and circulation over northern South America, which can also be reinforced by the Atlantic. Thus, depending on conditions in the Atlantic, the South American rainy season may be strongly affected. These results suggest that some care always must be taken in producing precipitation (and impacts) forecasts based on ENSO indices and composites alone.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
References
Aceituno, P. 1988. On the functioning of the Southern Oscillation in the South America sector. Monthly Weather Review 116(2): 505–524.
Alves, J.M.B., and C.A. Repelli. 1992. A variabilidade pluviométrica no setor norte do nordeste e os eventos El Niño/Oscilação Sul. Revista Brasileira de Meteorologia 7(2): 583–592.
Ambrizzi, T., and V. Magana. 1999. Dynamics of the impacts of El Niño/Southern Oscillation on the Americas climate: The December-January-February signal. In, 14th Conference on Hydrology, 79th AMS Annual Meeting, Dallas, Texas, 1: 307–308.
Ambrizzi, T., and V. Magana. Submitted. Climate variability in the tropical and subtropical mericas associated with El Niño/Southern Oscillation (ENSO). Climate Dynamics.
Bjerknes, J. 1969. Atmospheric teleconnections from the equatorial Pacific. Monthly Weather Review 97: 163–172.
Cane, M. 1992. Tropical Pacific ENSO models: ENSO as a mode of the coupled system. In, Renberth, K.E. (ed.). Climate System Modeling. Cambridge, UK: Cambridge University Press, pp. 583–614.
Casarin, D.P., and V.E. Kousky. 1986. Anomalias de precipitação no sul do Brasil e variações da circulação atmosférica. Revista Brasileira de Meteorologia 1: 83–90.
Chen, M., P. Xie, J.E. Janowiak, and P.A. Arkin. 2002. Global land precipitation: A 50 year onthly analysis based on gauge observations. Journal of Hydrometeorology 3(3): 49–266.
Chiang, J.C., Y. Kushnir, and A. Giannini. 2002. Deconstructing Atlantic Intertropical Convergence Zone ariability: Influence of the local cross-equatorial sea surface temperature gradient and remote forcing from the eastern equatorial Pacific. Journal of Geophysical Research 107(D 1): 1–19.
Coelho, C.A.S., A.R.M. Drumond, T. Ambrizzi, and G. Sampaio. 1998. Estudo climatológico sazonal da precipitação sobre o Brasil em episódios extremos da oscilação sul. Revista Brasileira de Meteorologia 14(1): 49–65.
Coelho, C.A.S., C.B. Uvo, and T. Ambrizzi. 2002. Exploring the impacts of the tropical Pacific SST on the precipitation patterns over South America during ENSO periods. Theoretical and Applied Climatology 71:185–197.
Diaz, A.F., C.D. Studzinski, and C.R. Mechoso. 1998. Relationships between precipitation anomalies in Uruguay and Southern Brazil and sea surface temperature in the Pacific and Atlantic Oceans. Journal of Climate 11: 251–271.
Dommenget, D., and M. Latif. 2000. Interannual to decadal variability in the tropical Atlantic. Journal of Climate 13: 777–792.
Enfield, D.B., and D.A. Mayer. 1997. Tropical Atlantic sea surface temperature variability and its relation to the El Niño-Southern Oscillation. Journal of Geophysical Research 102: 929–945.
Figueroa, S.N., P. Satyamurty, and P.L. Silva Dias. 1995. Simulations of the summer circulation over the South American region with an ETA coordinate model. Journal of the Atmospheric Sciences 52: 1573–1584.
Grimm, A.M., V.R. Barros, and M. Doyle. 2000. Climate variability in Southern South America associated with El Niño and La Nina events. Journal of Climate 13: 35–58.
Grimm, A.M., S.E.T. Ferraz, and J. Gomes. 1998. Precipitation anomalies in Southern Brazil associated with El Niño and La Nina events. Journal of Climate 11: 2863–2880.
Harrison, D.E., and N.K. Larkin. 1998. El Niño-Southern Oscillation sea surface temperature and wind anomalies, 1946–1993. Reviews of Geophysics 36(3): 353–399.
Hastenrath, S. 1985. Climate and Circulation of the Tropics. Dordrecht: D. Riedel, 312 pp.
Hastenrath, S. 2001. In search of zonal circulation in the equatorial Atlantic sector from the NCEP-NCAR reanalysis. International Journal of Climatology 21: 37–47.
Hastenrath, S. 2002. Dipoles, temperature gradients, and tropical climate anomalies. Bulletin of the American Meteorological Society 83(5): 735–738.
Hastenrath, S., and L. Greischar. 1993. Circulation mechanisms related to northeast Brazil rainfall anomalies. Journal of Geophysical Research 98(D3): 5093–5102.
Hastenrath, S., and L. Heller. 1977. Dynamics of climatic hazards in Northeast Brazil. Quarterly Journal of the Royal Meteorological Society 103(435): 77–92.
Hastenrath, S., and P. Lamb. 1977. Climatic Atlas of the Tropical Atlantic and Eastern Pacific Oceans. Madison: University of Wisconsin Press.
Hoerling, M.P., and A. Kumar. 2000. Understanding and predicting extratropical teleconnections related to ENSO. In, Diaz, H.F., and V. Markgraf (eds.). El Niño and the Southern Oscillation: Multiscale Variability and Global and Regional Impacts. Cambridge, UK: Cambridge University Press, pp. 57–88.
Kalnay, E., and co-authors. 1996. The NCEP/NCAR reanalysis project. Bulletin of the American Meteorological Society 77: 437–471.
Kayano, M.T., N.J. Ferreira, and M.C.V. Ramirez. 1997. Summer circulation patterns related to the upper tropospheric vortices over the tropical South Atlantic. Meteorology and Atmospheric Physics 64: 203–213.
Kidson, J.W. 1975. Tropical eigenvector analysis and the Southern Oscillation. Monthly Weather Review 103: 187–196.
Kiladis, G., and H.F. Diaz. 1989. Global climatic anomalies associated with extremes in the Southern Oscillation. Journal of Climate 2: 1069–1090.
Kousky, V.E., and M.A. Gan. 1981. Upper tropospheric cyclonic vortices in the tropical South Atlantic. Tellus 33: 538–551.
Kousky, V.E., and C. Ropelewski. 1989. Extremes in the Southern Oscillation and their relationship to precipitation with emphasis on the South American region. Revista Brasileira de Meteorologia 4: 351–363.
Kousky, V.E., I.F.A. Cavalcanti, and M.T. Kayano. 1984. A review of the Southern Oscillation: Oceanic-atmospheric circulation changes and related rainfall anomalies. Tellus 36A: 490–504.
Lau, K., and J. Zhou. 2003. Anomalies of the South American summer monsoon associated with the 1997–1999 ENSO. International Journal of Climatology 23: 529–539
Lau, N.G. 1997. Interactions between global SST anomalies and the midlatirude atmospheric circulation. Bulletin of the American Meteorological Society 78: 21–34.
Lau, N.G., and M.J. Nath. 1994. A modeling study of the relative roles of tropical and extratropical SST anomalies in the variability of the global atmosphere-ocean system. Journal of Climate 7: 1184–1207.
Liebmann, B., G.K. Kiladis, J.A. Marengo, T. Ambrizzi, and J.D. Glick. 1999. Submonthly convective variability over South America and the South Atlantic Convergence Zone. Journal of Climate 12: 1877–1891.
Moura, A.D., and J. Shukla. 1981. On the dynamics of droughts in northeast Brazil: Observations, theory and numerical experiments with a general circulation model. Journal of the Atmospheric Sciences 38(7): 2653–2675.
Nobre, P., and J. Shukla. 1996. Variations of sea surface temperature, wind stress and rainfall over the tropical Atlantic and South America. Journal of Climate 10(4): 2664–2479.
Nogués-Paegle, J., and K.C. Mo. 1997. Alternating wet and dry conditions over South America during summer. Monthly Weather Review 107: 279–291.
Oort, A.H., and J.J. Yienger. 1996. Observed interannual variability in the Hadley circulation and its connection to ENSO. Journal of Climate 9: 2751–2767.
Pezzi, L.P., and I.F.A. Cavalcanti. 2001. The relative importance of ENSO and tropical Atlantic SST anomalies for seasonal precipitation over South America: A numerical study. Climate Dynamics 17: 205–212.
Pulwarty, R.S. 1994. Annual and interannual variability of convection over tropical South America. Ph.D. thesis, University of Colorado, Boulder, 220 pp.
Pulwarty, R., and H. Diaz. 1993. A study of the seasonal cycle and its perturbation by ENSO events over the tropical Americas. In, Fourth International Conference on Southern Hemisphere Meteorology and Oceanography, March 29-April 2, 1993, Hobart, Australia.
Rao, V.B., and K. Hada. 1990. Characteristics of rainfall over Brazil: Annual variation and connections with the Southern Oscillation. Theoretical and Applied Climatology 42:81–91.
Rao, V.B., I.F.A. Cavalcanti, and K. Hada. 1996. Annual variations of rainfall over Brazil and water vapor characteristics of South America. Journal of Geophysical Research 101:36350–36551.
Ropelewski, C, and M.S. Halpert. 1987. Global and regional scale precipitation patterns associated with the El Niño-Southern Oscillation. Monthly Weather Review 115(2): 1606–1626.
Ropelewski, C, and M.S. Halpert. 1989. Precipitation patterns associated with the high index phase of the Southern Oscillation. Journal of Climate 2: 268–284.
Servain, J. 1991. Simple climate indices for the tropical Atlantic Ocean and some applications. Journal of Geophysical Research 96: 15137–15146.
Smith, T.M., R.W. Reynolds, R.E. Livezey, and D.C. Stokes. 1996. Reconstruction of historical sea surface temperature using empirical orthogonal functions. Journal of Climate 9: 1403–1420.
Souza, E.B., and T. Ambrizzi. 2002. ENSO impacts on the South American rainfall during 1980s: Hadley and Walker circulation. Atmñsfera 15: 105–120.
Souza, E.B., and P. Nobre. 1998. Uma revisão sobre o Padrão de Dipolo no Oceano Atlântico tropical. Revista Brasileira de Meteorologia 13(1): 31–44.
Souza, E.B., T. Ambrizzi, and C.A.S. Coelho. In press. Two ENSO episodes with reversed impacts on the regional precipitation of the northeastern South America. Meteorológica.
Souza, E.B., J.M.B. Alves, and P. Nobre. 1998. Anomalias de precipitação no norte e leste do Nordeste Brasileiro em associação aos eventos do Padrão de Dipolo observados no Atlântico tropical. Revista Brasileira de Meteorologia 13(1): 31–44.
Souza, E.B., M.T. Kayano, J. Tota, L. Pezzi, G. Fisch, and C. Nobre. 2000. On the influences of the El Niño, La Nina and Atlantic dipole pattern on the Amazonian rainfall during 1960–1998. Acta Amazonica 30(2): 305–318.
Trenberth, K.E. 1997. The definition of El Niño. Bulletin of the American Meteorological Society 78: 2771–2777.
Trenberth, K.E., and J.M. Caron. 2000. The Southern Oscillation revisited: Sea level pressures, surface temperatures and precipitation. Journal of Climate 13: 4358–4365.
Trenberth, K.E., and D.P. Stepaniak. 2003. Seamless poleward atmospheric energy transports and implications for the Hadley circulation. Journal of Climate 16: 3706–3722.
Trenberth, K.E., D.P. Stepaniak, and J.M. Caron. 2000. The global monsoon as seen through the divergent atmospheric circulation. Journal of Climate 13: 3969–3993.
Uvo, C.R.B., C.A. Repelli, S. Zebiak, and Y. Kushnir. 1998. The relationships between tropical Pacific and Atlantic SST and northeast Brazil monthly precipitation. Journal of Climate 11(4): 551–562.
Virji, H. 1981. A preliminary study of summertime tropospheric circulation patterns over South America estimated from cloud winds. Monthly Weather Review 109: 599–610.
Wagner, R.G. 1996. Mechanisms controlling variability of the interhemispheric sea surface temperature gradient in the tropical Atlantic. Journal of Climate 9(7): 2010–2019.
Wang, C. 2002. Atmospheric circulation cells associated with the El Niño-Southern Oscillation. Journal of Climate 15: 399–419.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2004 Kluwer Academic Publishers
About this chapter
Cite this chapter
Ambrizzi, T., de Souza, E.B., Pulwarty, R.S. (2004). The Hadley and Walker Regional Circulations and Associated ENSO Impacts on South American Seasonal Rainfall. In: Diaz, H.F., Bradley, R.S. (eds) The Hadley Circulation: Present, Past and Future. Advances in Global Change Research, vol 21. Springer, Dordrecht. https://doi.org/10.1007/978-1-4020-2944-8_8
Download citation
DOI: https://doi.org/10.1007/978-1-4020-2944-8_8
Publisher Name: Springer, Dordrecht
Print ISBN: 978-90-481-6752-4
Online ISBN: 978-1-4020-2944-8
eBook Packages: Springer Book Archive