Editorial Type:
Article
Article Type:
Research Article

Intraseasonal and Interannual Variability of Extreme Dry and Wet Events over Southeastern South America and the Subtropical Atlantic during Austral Summer

Michel N. Muza Department of Atmospheric Sciences, University of São Paulo, São Paulo, Brazil

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Leila M. V. Carvalho Department of Atmospheric Sciences, University of São Paulo, São Paulo, Brazil, and Institute for Computational Earth System Sciences, University of California, Santa Barbara, Santa Barbara, California

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Charles Jones Institute for Computational Earth System Sciences, University of California, Santa Barbara, Santa Barbara, California

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Brant Liebmann CIRES Climate Diagnostics Center, Boulder, Colorado

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Print Publication:
01 Apr 2009
DOI:
https://doi.org/10.1175/2008JCLI2257.1
Page(s):
1682–1699
Restricted access

Abstract

Intraseasonal and interannual variability of extreme wet and dry anomalies over southeastern Brazil and the western subtropical South Atlantic Ocean are investigated. Precipitation data are obtained from the Global Precipitation Climatology Project (GPCP) in pentads during 23 austral summers (December–February 1979/80–2001/02). Extreme wet (dry) events are defined according to 75th (25th) percentiles of precipitation anomaly distributions observed in two time scales: intraseasonal and interannual. The agreement between the 25th and 75th percentiles of the GPCP precipitation and gridded precipitation obtained from stations in Brazil is also examined. Variations of extreme wet and dry anomalies on interannual time scales are investigated along with variations of sea surface temperature (SST) and circulation anomalies. The South Atlantic SST dipole seems related to interannual variations of extreme precipitation events over southeastern Brazil. It is shown that extreme wet and dry events in the continental portion of the South Atlantic convergence zone (SACZ) are decoupled from extremes over the oceanic portion of the SACZ and there is no coherent dipole of extreme precipitation regimes between tropics and subtropics on interannual time scales. On intraseasonal time scales, the occurrence of extreme dry and wet events depends on the propagation phase of extratropical wave trains and consequent intensification (weakening) of 200-hPa zonal winds. Extreme wet and dry events over southeastern Brazil and subtropical Atlantic are in phase on intraseasonal time scales. Extreme wet events over southeastern Brazil and subtropical Atlantic are observed in association with low-level northerly winds above the 75th percentile of the seasonal climatology over central-eastern South America. Extreme wet events on intraseasonal time scales over southeastern Brazil are more frequent during seasons not classified as extreme wet or dry on interannual time scales.

Corresponding author address: Michel Nobre Muza, Department of Atmospheric Sciences, University of São Paulo, 1226, R. do Matão, São Paulo, SP 05508–900 Brazil. Email: michelnm@model.iag.usp.br

Abstract

Intraseasonal and interannual variability of extreme wet and dry anomalies over southeastern Brazil and the western subtropical South Atlantic Ocean are investigated. Precipitation data are obtained from the Global Precipitation Climatology Project (GPCP) in pentads during 23 austral summers (December–February 1979/80–2001/02). Extreme wet (dry) events are defined according to 75th (25th) percentiles of precipitation anomaly distributions observed in two time scales: intraseasonal and interannual. The agreement between the 25th and 75th percentiles of the GPCP precipitation and gridded precipitation obtained from stations in Brazil is also examined. Variations of extreme wet and dry anomalies on interannual time scales are investigated along with variations of sea surface temperature (SST) and circulation anomalies. The South Atlantic SST dipole seems related to interannual variations of extreme precipitation events over southeastern Brazil. It is shown that extreme wet and dry events in the continental portion of the South Atlantic convergence zone (SACZ) are decoupled from extremes over the oceanic portion of the SACZ and there is no coherent dipole of extreme precipitation regimes between tropics and subtropics on interannual time scales. On intraseasonal time scales, the occurrence of extreme dry and wet events depends on the propagation phase of extratropical wave trains and consequent intensification (weakening) of 200-hPa zonal winds. Extreme wet and dry events over southeastern Brazil and subtropical Atlantic are in phase on intraseasonal time scales. Extreme wet events over southeastern Brazil and subtropical Atlantic are observed in association with low-level northerly winds above the 75th percentile of the seasonal climatology over central-eastern South America. Extreme wet events on intraseasonal time scales over southeastern Brazil are more frequent during seasons not classified as extreme wet or dry on interannual time scales.

Corresponding author address: Michel Nobre Muza, Department of Atmospheric Sciences, University of São Paulo, 1226, R. do Matão, São Paulo, SP 05508–900 Brazil. Email: michelnm@model.iag.usp.br

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  • Carvalho, L. M. V., C. Jones, and B. Liebmann, 2002a: Extreme precipitation events in southeastern South America and large-scale convective patterns in the South Atlantic convergence zone. J. Climate, 15 , 2377–2394.

    • Search Google Scholar
    • Export Citation

  • Carvalho, L. M. V., C. Jones, and M. A. F. Silva Dias, 2002b: Intraseasonal large-scale circulations and mesoscale convective activity in tropical South America during the TRMM-LBA campaign. J. Geophys. Res., 107 , 8042. doi:10.1029/2001JD000745.

    • Search Google Scholar
    • Export Citation

  • Carvalho, L. M. V., D. Lavallée, and C. Jones, 2002c: Multifractal properties of evolving convective systems over tropical South America. Geophys. Res. Lett., 29 , 1743. doi:10.1029/2001GL014276.

    • Search Google Scholar
    • Export Citation

  • Carvalho, L. M. V., C. Jones, and B. Liebman, 2004: The South Atlantic convergence zone: Intensity, form, persistence, relationships with intraseasonal to interannual activity and extreme rainfall. J. Climate, 17 , 88–108.

    • Search Google Scholar
    • Export Citation

  • Carvalho, L. M. V., D. Lavallée, and T. Ambrizzi, 2005: Opposite phases of the Antarctic Oscillation and relationships with intraseasonal to interannual activity in the tropics during the austral summer. J. Climate, 18 , 702–718.

    • Search Google Scholar
    • Export Citation

  • Casarin, D. P., and V. E. Kousky, 1986: Anomalias de precipitação no sul do Brasil e variações na circulação atmosférica. Res. Bras. Meteor., 1 , 83–90.

    • Search Google Scholar
    • Export Citation

  • Ferranti, L., T. N. Palmer, F. Monteni, and E. Klinker, 1990: Tropical–extratropical interaction associated with the 30–60-day oscillation and its impact on medium range and extended range prediction. J. Atmos. Sci., 47 , 2177–2199.

    • Search Google Scholar
    • Export Citation

  • Figueroa, S. N., P. Satyamyrty, and P. L. Silva-Dias, 1995: Simulations of the summer circulation over the South American region with an ETA coordinate model. J. Atmos. Sci., 52 , 1573–1584.

    • Search Google Scholar
    • Export Citation

  • Gan, M. A., V. E. Kousky, and C. F. Ropelewski, 2004: The South America monsoon circulation and its relationship to rainfall over west-central Brazil. J. Climate, 17 , 47–66.

    • Search Google Scholar
    • Export Citation

  • Grimm, A. M., 2003: The El Niño impact on the summer monsoon in Brazil: Regional processes versus remote influences. J. Climate, 16 , 263–280.

    • Search Google Scholar
    • Export Citation

  • Grimm, A. M., and P. L. Silva Dias, 1995: Analysis of tropical–extratropical interactions with influence functions of a barotropic model. J. Atmos. Sci., 52 , 3538–3555.

    • Search Google Scholar
    • Export Citation

  • Herdies, D. L., A. da Silva, A. Silva Dias, and R. Nieto-Ferrari, 2002: Moisture budget of the bimodal pattern of the summer circulation over South America: Large-scale biosphere–atmosphere experiment in Amazonia (LBA). J. Geophys. Res., 107 , 8075. doi:10.1029/2001JD000997.

    • Search Google Scholar
    • Export Citation

  • Jones, C., and L. M. V. Carvalho, 2002: Active and break phases in the South American monsoon system. J. Climate, 15 , 905–914.

  • Jones, C., D. E. Waliser, and E. C. Gautier, 1998: The influence of the Madden–Julian oscillation on ocean surface heat fluxes and sea surface temperature. J. Climate, 11 , 1057–1072.

    • Search Google Scholar
    • Export Citation

  • Jones, C., D. E. Waliser, K. M. Lau, and W. Stern, 2004: Global occurrences of extreme precipitation events and the Madden–Julian oscillation: Observations and predictability. J. Climate, 17 , 4575–4589.

    • Search Google Scholar
    • Export Citation

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR Reanalysis 40-Year Project. Bull. Amer. Meteor. Soc., 77 , 437–471.

  • Karoly, D. J., 1989: Southern Hemisphere circulation features associated with El Niño–Southern Oscillation events. J. Climate, 2 , 1239–1252.

    • Search Google Scholar
    • Export Citation

  • Kodama, Y. M., 1992: Large-scale common features of subtropical precipitation zones (the Baiu frontal zone, the SPCZ, and the SACZ). Part I: Characteristics of subtropical frontal zones. J. Meteor. Soc. Japan, 70 , 813–835.

    • Search Google Scholar
    • Export Citation

  • Kodama, Y. M., 1993: Large-scale common features of subtropical precipitation zones (the Baiu frontal zone, the SPCZ, and the SACZ). Part II: Conditions of the circulation and tropical convection over the Pacific. J. Meteor. Soc. Japan, 71 , 581–610.

    • Search Google Scholar
    • Export Citation

  • Kousky, V. E., and M. T. Kayano, 1994: Principal modes of outgoing longwave radiation and 250-mb circulation for the South American sector. J. Climate, 7 , 1131–1143.

    • Search Google Scholar
    • Export Citation

  • Lenters, J. D., and K. H. Cook, 1999: Summertime precipitation variability over South America: Role of the large-scale circulation. Mon. Wea. Rev., 127 , 409–431.

    • Search Google Scholar
    • Export Citation

  • Liebmann, B., and C. Smith, 1996: Description of a complete (interpolated) outgoing longwave radiation dataset. Bull. Amer. Meteor. Soc., 77 , 1275–1277.

    • Search Google Scholar
    • Export Citation

  • Liebmann, B., and J. A. Marengo, 2001: Interannual variability of the rainy season and rainfall in the Brazilian Amazon basin. J. Climate, 14 , 4308–4318.

    • Search Google Scholar
    • Export Citation

  • Liebmann, B., and D. Allured, 2005: Daily precipitation grids for South America. Bull. Amer. Meteor. Soc., 86 , 1567–1570.

  • Liebmann, B., G. N. Kiladis, J. A. Marengo, T. Ambrizzi, and J. D. Glick, 1999: Submonthly convective variability over South America and the South Atlantic convergence zone. J. Climate, 12 , 1877–1891.

    • Search Google Scholar
    • Export Citation

  • Liebmann, B., C. Jones, and L. M. V. Carvalho, 2001: Interannual variability of extreme precipitation events in the state of São Paulo, Brazil. J. Climate, 14 , 208–218.

    • Search Google Scholar
    • Export Citation

  • Liebmann, B., G. N. Kiladis, C. S. Vera, A. C. Saulo, and L. M. V. Carvalho, 2004: Subseasonal variations of rainfall in South America in the vicinity of the low-level jet east of the Andes and comparison to those in the South Atlantic convergence zone. J. Climate, 17 , 3829–3842.

    • Search Google Scholar
    • Export Citation

  • Marengo, J. A., B. Liebmann, V. E. Kousky, N. P. Filizola, and I. C. Wainer, 2001: Onset and end of the rainy season in the Brazilian Amazon basin. J. Climate, 14 , 833–852.

    • Search Google Scholar
    • Export Citation

  • Mo, K. C., and J. Nogués-Paegle, 2001: The Pacific–South American modes and their downstream effects. Int. J. Climatol., 21 , 1211–1229.

    • Search Google Scholar
    • Export Citation

  • Nogués-Paegle, J., and K. C. Mo, 1997: Alternating wet and dry conditions over South America during summer. Mon. Wea. Rev., 125 , 279–291.

    • Search Google Scholar
    • Export Citation

  • Nogués-Paegle, J., L. A. Byerle, and K. C. Mo, 2000: Intraseasonal modulation of South American summer precipitation. Mon. Wea. Rev., 128 , 837–850.

    • Search Google Scholar
    • Export Citation

  • Robertson, A. W., and C. R. Mechoso, 2000: Interannual and interdecadal variability of the South Atlantic convergence zone. Mon. Wea. Rev., 128 , 2947–2957.

    • Search Google Scholar
    • Export Citation

  • Ropelewski, C. F., and M. S. Halpert, 1987: Global and regional scale precipitation patterns associated with the El Niño/Southern Oscillation. Mon. Wea. Rev., 115 , 1606–1626.

    • Search Google Scholar
    • Export Citation

  • Silva, A. E., and L. M. V. Carvalho, 2007: Large-scale index for South America monsoon (LISAM). Atmos. Sci. Lett., 8 , 51–57.

  • Spiegel, M. R., J. J. Schiller, and A. L. Srinivasan, 2000: Schaum’s Outline of Probability and Statistics. McGraw-Hill, 220 pp.

  • Vera, C., and Coauthors, 2006: Toward a unified view of the American monsoon systems. J. Climate, 19 , 4977–5000.

  • Weickmann, K. M., G. R. Lussky, and J. E. Kutzbach, 1985: Intraseasonal (30–60 day) fluctuation of outgoing longwave radiation and 250-mb streamfunction during northern winter. Mon. Wea. Rev., 113 , 941–961.

    • Search Google Scholar
    • Export Citation

  • Wilks, D. S., 1995: Statistical Methods in the Atmospheric Sciences. Academic Press, 467 pp.

  • Xie, P., and Coauthors, 2003: GPCP pentad precipitation analyses: An experimental dataset based on gauge observations and satellite estimates. J. Climate, 16 , 2197–2214.

    • Search Google Scholar
    • Export Citation

  • Zhou, J., and K. M. Lau, 1998: Does a monsoon climate exist over South America? J. Climate, 11 , 1020–1040.

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