The El Niño Impact on the Summer Monsoon in Brazil: Regional Processes versus Remote Influences

Grimm, Alice M.

doi:10.1175/1520-0442(2003)016<0263:teniot>2.0.co;2

Cited by 347 publications

(483 citation statements)

References 20 publications

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“…The transition between these climatic spaces happens roughly around the Rio Doce-a known biogeographic divide [38,39]. This major bioclimatic transition also matches patterns of species turnover between the northern and the southern portions of the AF based on locality data for 25 vertebrate species (figure 1), published observations of precipitation seasonality discontinuities [29], as well as faunal changes revealed by panbiogeographical analyses [40]. This demonstrates that the geographical patterns of environmental shifts along the AF are intimately linked to the current and former distribution of its fauna and flora, and may suggest a climate-physiological basis, rather than river-associated vicariance [41], for the observed patterns of diversity and endemism.…”

Section: Discussionsupporting

confidence: 75%

Prediction of phylogeographic endemism in an environmentally complex biome

et al. 2014

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Phylogeographic endemism, the degree to which the history of recently evolved lineages is spatially restricted, reflects fundamental evolutionary processes such as cryptic divergence, adaptation and biological responses to environmental heterogeneity. Attempts to explain the extraordinary diversity of the tropics, which often includes deep phylogeographic structure, frequently invoke interactions of climate variability across space, time and topography. To evaluate historical versus contemporary drivers of phylogeographic endemism in a tropical system, we analyse the effects of current and past climatic variation on the genetic diversity of 25 vertebrates in the Brazilian Atlantic rainforest. We identify two divergent bioclimatic domains within the forest and high turnover around the Rio Doce. Independent modelling of these domains demonstrates that endemism patterns are subject to different climatic drivers. Past climate dynamics, specifically areas of relative stability, predict phylogeographic endemism in the north. Conversely, contemporary climatic heterogeneity better explains endemism in the south. These results accord with recent speleothem and fossil pollen studies, suggesting that climatic variability through the last 250 kyr impacted the northern and the southern forests differently. Incorporating sub-regional differences in climate dynamics will enhance our ability to understand those processes shaping high phylogeographic and species endemism, in the Neotropics and beyond.

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Section: Discussionsupporting

confidence: 75%

Prediction of phylogeographic endemism in an environmentally complex biome

et al. 2014

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“…On the contrary, rainfall tends to be slightly more abundant during El Niño events in western and Figure 11. JJA differences between 1986-1997 and 1967-1976 in (a) southern Amazon, as reported by Ronchail (1998), Ronchail et al (2002Ronchail et al ( , 2005, Bendix et al (2003), Grimm (2003Grimm ( , 2004, and Ronchail and Gallaire (2006). The correlation between these PCs and the annual difference between the northern and SATL SSTs is also significant at the 99% level (r = −0.59 in DJF and r = −0.48 in MAM).…”

Section: Interannual Variabilitysupporting

confidence: 74%

“…In Brazil, regionalization is similar to that found by Hiez et al (1991). On the other hand, the use of annual pluviometric indexes from RVM allows the analysis period to be extended to 1964-2003.…”

Section: Interannual Variabilitymentioning

confidence: 99%

Spatio‐temporal rainfall variability in the Amazon basin countries (Brazil, Peru, Bolivia, Colombia, and Ecuador)

Espinoza

Ronchail

Guyot

et al. 2008

Intl Journal of Climatology

448

265

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Rainfall variability in the Amazon basin (AB) is analysed for the 1964-2003 period. It is based on 756 pluviometric stations distributed throughout the AB countries. For the first time it includes data from Bolivia, Peru, Ecuador, and Colombia. In particular, the recent availability of rainfall data from the Andean countries makes it possible to complete previous studies. The impact of mountain ranges on rainfall is pointed out. The highest rainfall in the AB is observed in low windward regions, and low rainfall is measured in leeward and elevated stations. Additionally, rainfall regimes are more diversified in the Andean regions than in the lowlands. Rainfall spatio-temporal variability is studied based on a varimax-rotated principal component analysis (PCA). Long-term variability with a decreasing rainfall since the 1980s prevails in June-July-August (JJA) and September-October-November (SON). During the rainiest seasons, i.e. December-January-February (DJF) and March-April-May (MAM), the main variability is at decadal and interannual time scales. Interdecadal variability is related to long-term changes in the Pacific Ocean, whereas decadal variability, opposing the northwest and the south of the AB, is associated with changes in the strength of the low-level jet (LLJ) along the Andes. Interannual variability characterizes more specifically the northeast of the basin and the southern tropical Andes. It is related to El Niño-Southern Oscillation (ENSO) and to the sea surface temperature (SST) gradient over the tropical Atlantic. Mean rainfall in the basin decreases during the 1975-2003 period at an annual rate estimated to be −0.32%. Break tests show that this decrease has been particularly important since 1982. Further insights into this phenomenon will permit to identify the impact of climate on the hydrology of the AB.

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“…ern Oscillation (ENSO) are also detected over parts of South America including the SACZ (Ropelewski and Halpert 1987;Grimm 2003;Robertson and Mechoso 2000;Liebmann et al 2001;Carvalho et al 2002).…”

Section: Introductionmentioning

confidence: 99%

The South Atlantic Convergence Zone: Intensity, Form, Persistence, and Relationships with Intraseasonal to Interannual Activity and Extreme Rainfall

2004

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The characteristics of intensity, geographical location, and persistence of the South Atlantic convergence zone (SACZ) during the austral summer are investigated. Intensity and spatial features of the SACZ are identified by performing a factor analysis of structural properties of outgoing longwave radiation (OLR) data. The first two leading factors explain 65% of the total variance of structural properties and characterize the SACZ according to intensity and location (oceanic versus continental). An index is constructed based on the magnitude of the factor scores to identify intense (weak) and oceanic (continental) SACZ. The intense SACZ category is associated with negative OLR anomalies over a large area of tropical South America, extending from the western Amazon to the Atlantic Ocean. The weak SACZ category is observed with positive OLR anomalies over tropical South America and negative OLR anomalies over southeastern South America. Oceanic and continental aspects of the SACZ are related to a midlatitude wave train pattern. The Madden-Julian oscillation (MJO) modulates intense SACZ events with persistence longer than 3 days. Interannual variability of persistent events indicates that the ratio of oceanic to continental SACZ as well as their frequency depends on the phase of El Niño-Southern Oscillation (ENSO). Occurrence of extreme rainfall in Brazil is discussed in the context of variations in the SACZ and MJO. Intense (weak) SACZ increases (decreases) the 95th daily rainfall percentile over centraleastern Brazil compared to the climatology. Oceanic (continental) SACZ increases (decreases) the 95th daily rainfall percentile over southeastern Brazil. The MJO phase characterized by suppression of convective activity over Indonesia and enhancement over the central Pacific increases the 95th daily rainfall percentile over northnortheastern Brazil, whereas opposite features are observed for the phase of the MJO characterized by the enhancement of convection over Indonesia and suppression over the central Pacific.

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The El Niño Impact on the Summer Monsoon in Brazil: Regional Processes versus Remote Influences

Cited by 347 publications

References 20 publications

Prediction of phylogeographic endemism in an environmentally complex biome

Prediction of phylogeographic endemism in an environmentally complex biome

Spatio‐temporal rainfall variability in the Amazon basin countries (Brazil, Peru, Bolivia, Colombia, and Ecuador)

The South Atlantic Convergence Zone: Intensity, Form, Persistence, and Relationships with Intraseasonal to Interannual Activity and Extreme Rainfall

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