Intraseasonal Modulation of South American Summer Precipitation

Paegle, Jan; Byerle, Lee A.; Mo, Kingtse C.

doi:10.1175/1520-0493(2000)128<0837:imosas>2.0.co;2

Cited by 187 publications

(93 citation statements)

References 15 publications

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“…Inversely, in southern South America and the adjacent subtropical Pacific there is an upper-level cyclonic circulation anomaly with diffluent moisture and suppressed convection below (Figure 8(a), (b)). This meridional convective dipole resembles the SACZ features that are well documented in the literature (Nogues- Paegle and Mo, 1997;Liebmann et al, 1999;Paegle et al, 2000;Carvalho et al, 2004) but with its climatological position slightly shifted northward. These regional mechanisms observed during the peak of the intraseasonal rainfall events over tropical Brazil are dynamically embedded within the eastward-propagating MJO-related large-scale convective envelope along tropical South America/the Atlantic Ocean.…”

Section: Regional Mechanisms Over South America/the Atlantic Oceanmentioning

confidence: 85%

“…Other studies with a regional focus were able to detect significant intraseasonal variability over tropical (Kousky and Kayano, 1994;Carvalho et al, 2002;Souza et al, 2005) and subtropical South America with emphasis on the South Atlantic Convergence Zone (SACZ) (Casarin and Kousky, 1986;Nogues-Paegle and Mo, 1997;Liebmann et al, 1999;Grimm et al, 2000;Paegle et al, 2000;Todd et al, 2003;Carvalho et al, 2004), which is dynamically linked with MJO events (Kiladis and Weickmann, 1992;Grimm and Silva Dias, 1995). In addition, Jones et al (2004) reported unambiguous and robust signals of an increased frequency of precipitation extremes in the eastern part of South America during active MJO events.…”

Section: Introductionmentioning

confidence: 99%

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Modulation of the intraseasonal rainfall over tropical Brazil by the Madden–Julian oscillation

Souza¹,

Ambrizzi

2006

Int. J. Climatol.

100

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Fifteen years (1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001) of rain gauge-based data are used to describe the intraseasonal rainfall variability over tropical Brazil and its associated dynamical structure. Wavelet analysis performed on rainfall time series showed significant peaks centered roughly in periods of 30-70 days, particularly in the eastern southeastern Amazon and northern northeast Brazil. A significant enhancement of precipitation with maximum anomalies in a northeastward oriented band over tropical Brazil is evidenced from empirical orthogonal function (EOF) analysis of 30-70-day filtered rainfall anomalies during rainy season (January to May). Lagged/lead composites revealed that, on a global scale, the Madden-Julian oscillation (MJO) is the main atmospheric-mechanism modulator of the pluviometric variations on intraseasonal timescale in the eastern Amazon and northeast Brazil. A coherent northward expansion of rainfall across tropical Brazil is evident during the passage of MJO over South America. Regionally, the establishment of a quasi-stationary deep convection band triggered by the simultaneous manifestation of south Atlantic convergence zone (SACZ) and intertropical convergence zone (ITCZ) explains the intensified rainfall over these regions. Such regional mechanisms are dynamically embedded within the eastward-propagating MJO-related large-scale convective envelope along tropical South America/the Atlantic Ocean. These features occur in association with a significant intraseasonal evolution of the lower-level wind and seasurface temperature (SST) patterns, particularly in the Atlantic Ocean, including a coherent dynamical connection with atmospheric circulation, deep convective activity over South America and rainfall over tropical Brazil.

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Section: Regional Mechanisms Over South America/the Atlantic Oceanmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Modulation of the intraseasonal rainfall over tropical Brazil by the Madden–Julian oscillation

Souza¹,

Ambrizzi

2006

Int. J. Climatol.

100

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“…Singular spectrum analysis is an extension of principal components for time series, ⇤ with applications in climatology (Allen and Smith, 1996), geophysics (Kondrashov and Ghil, 2006), and meteorology (Paegle et al, 2000); other applications include forecasting (Hassani et al, 2009). The business cycle indicator yielded through this method resembles band-pass filtered output, it is in line with the contraction periods dated by the NBER, and a real-time exercise indicates it possesses better revision performance than some competing filters.…”

Section: Introductionmentioning

confidence: 80%

Tracking the US business cycle with a singular spectrum analysis

2012

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“…The PSA modes contain both the MJO and the 22-day mode signals (N-Paegle and Mo, 1997;N-Paegle et al, 2000). However, the association with tropical convection is dominant by the MJO.…”

Section: Discussionmentioning

confidence: 99%

“…In the intraseasonal band, Mo and Higgins (1998) found that the PSA patterns are modulated by tropical convection associated with the Madden Julian Oscillation (MJO) during winter. N-Paegle and Mo (1997) and N-Paegle et al (2000) link some classes of summer precipitation over South America to the MJO.…”

Section: Introductionmentioning

confidence: 99%

The Pacific–South American modes and their downstream effects

Paegle

2001

Intl Journal of Climatology

Self Cite

322

228

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There are two pervasive modes of atmospheric variability in the Southern Hemisphere (SH) that influence circulation and rainfall anomalies over South America. They appear as leading empirical orthogonal functions (EOFs) of 500-hPa height or 200-hPa streamfunction anomalies and are found from intraseasonal to decadal time scales. Both patterns exhibit wave 3 hemispheric patterns in mid to high latitudes, and a well-defined wave train with large amplitude in the Pacific-South American (PSA) sector. Therefore, they are referred to as the PSA modes (PSA1 and PSA2).PSA1 is related to sea surface temperature anomalies (SSTAs) over the central and eastern Pacific at decadal scales, and it is the response to El Niñ o-Southern Oscillation (ENSO) in the interannual band. The associated rainfall summer pattern shows rainfall deficits over northeastern Brazil and enhanced rainfall over southeastern South America similar to rainfall anomalies during ENSO. PSA2 is associated with the quasi-biennial component of ENSO, with a period of 22-28 months and the strongest connections occur during the austral spring. The associated rainfall pattern shows a dipole pattern with anomalies out of phase between the South Atlantic Convergence Zone (SACZ) extending from central South America into the Atlantic and the subtropical plains centred at 35°S.These two modes are also apparent in tropical intraseasonal oscillations for both summer and winter. Eastward propagation of enhanced convection from the Indian Ocean through the western Pacific to the central Pacific is accompanied by a wave train that appears to originate in the convective regions. The positive PSA1 pattern is associated with enhanced convection over the Pacific from 150°E to the date line. The convection pattern associated with PSA2 is in quadrature with that of PSA1. Both PSA modes are influenced by the Madden Julian Oscillation and influence rainfall over South America.

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Intraseasonal Modulation of South American Summer Precipitation

Cited by 187 publications

References 15 publications

Modulation of the intraseasonal rainfall over tropical Brazil by the Madden–Julian oscillation

Modulation of the intraseasonal rainfall over tropical Brazil by the Madden–Julian oscillation

Tracking the US business cycle with a singular spectrum analysis

The Pacific–South American modes and their downstream effects

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