The joint impacts of Atlantic and Pacific multidecadal variability on South American precipitation and temperature

2021 ◽  
pp. 1-55
Author(s):  
Zhaoxiangrui He ◽  
Aiguo Dai ◽  
Mathias Vuille
Keyword(s):  
South America ◽  
The Other ◽  
South American ◽  
Atlantic Multidecadal Variability ◽  
Multidecadal Variability ◽  
Temperature Anomalies ◽  
Central Brazil ◽  
Eastern Brazil ◽  
Precipitation Anomalies ◽  
Central Eastern

AbstractSouth American climate is influenced by both Atlantic multidecadal variability (AMV) and Pacific multidecadal variability (PMV). But how they jointly affect South American precipitation and surface air temperature is not well understood. Here we analyze composite anomalies to quantify their combined impacts using observations and reanalysis data. During an AMV warm (cold) phase, PMV-induced JJA precipitation anomalies are more positive (negative) over 0°-10°S and southeastern South America, but more negative (positive) over the northern Amazon and central Brazil. PMV-induced precipitation anomalies in DJF are more positive (negative) over Northeast Brazil and southeastern South America during the warm (cold) AMV phase, but more negative (positive) over the central Amazon Basin and central-eastern Brazil. PMV’s impact on AMV-induced precipitation anomalies shows similar dipole patterns. The precipitation changes result from perturbations of the local Hadley and Walker Circulations. In JJA, PMV- and AMV-induced temperature anomalies are more positive (negative) over entire South America when the other basin is in a warm (cold) phase, but in DJF temperature anomalies are more positive (negative) only over the central Andes and central-eastern Brazil and more negative (positive) over southeastern South America and Patagonia. Over central Brazil in JJA and southern Bolivia and northern Argentina in DJF, the temperature and precipitation anomalies are negatively correlated. Our results show that the influence of Pacific and Atlantic multidecadal variability need to be considered jointly, as significant departures from the mean AMV or PMV fingerprint can occur during a cold or warm phase of the other basin’s mode.

scholarly journals Interdecadal Variability of Southeastern South America Rainfall and Moisture Sources during the Austral Summertime

2016 ◽  
Vol 29 (18) ◽  
pp. 6751-6763 ◽  
Author(s):  
Verónica Martín-Gómez ◽  
Emilio Hernández-Garcia ◽  
Marcelo Barreiro ◽  
Cristóbal López
Keyword(s):  
South America ◽  
Rainfall Variability ◽  
Austral Summer ◽  
Eastern Shore ◽  
Central Brazil ◽  
Moisture Sources ◽  
Tropical Oceans ◽  
Eastern Brazil ◽  
Central Eastern ◽  
Atmospheric Circulation Anomalies

Abstract Sea surface temperature (SST) anomalies over the tropical oceans are able to generate extratropical atmospheric circulation anomalies that can induce rainfall variability and changes in the sources of moisture. The work reported here evaluates the interdecadal changes in the moisture sources for southeastern South America (SESA) during austral summer, and it is divided into two complementary parts. In the first part the authors construct a climate network to detect synchronization periods among the tropical oceans and the precipitation over SESA. Afterward, taking into account these results, the authors select two periods with different degrees of synchronization to compare the spatial distribution of the SESA moisture sources. Results show that during the last century there were three synchronization periods among the tropical oceans and the precipitation over SESA (during the 1930s, 1970s, and 1990s) and suggest that the main moisture sources of SESA are the recycling over the region, the central-eastern shore of Brazil together with the surrounding Atlantic Ocean, and the southwestern South Atlantic surrounding the SESA domain. Comparison of SESA moisture sources for the 1980s (a period of nonsignificant synchronization) and the 1990s (a synchronized period) shows that the principal differences are in the intensity of the recycling and in the strength of the central-eastern shore of Brazil. Moreover, the authors find that a region centered at (20°S, 300°E) is a moisture source for SESA only during the 1990s. These differences can be associated with the development of a low-level anticyclonic (cyclonic) anomaly circulation over central-eastern Brazil that favors the transport of moisture from central Brazil (central-eastern shore of Brazil) toward SESA in the 1990s (1980s).

scholarly journals Multiple incursion pathways for Helicoverpa armigera in Brazil show its genetic diversity spreading in a connected world

2019 ◽  
Author(s):  
Jonas A. Arnemann ◽  
Stephen H. Roxburgh ◽  
Tom Walsh ◽  
Jerson V.C. Guedes ◽  
Karl H.J. Gordon ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Gene Flow ◽  
South America ◽  
New World ◽  
Flow Patterns ◽  
South American ◽  
Southern Brazil ◽  
American Continent ◽  
Central Brazil ◽  
South American Continent

AbstractThe Old World cotton bollworm Helicoverpa armigera was first detected in Brazil with subsequent reports from Paraguay, Argentina, Bolivia, and Uruguay. This pattern suggests that the H. armigera spread across the South American continent following incursions into northern/central Brazil, however, this hypothesis has not been tested. Here we compare northern and central Brazilian H. armigera mtDNA COI haplotypes with those from southern Brazil, Uruguay, Argentina, and Paraguay. We infer spatial genetic and gene flow patterns of this dispersive pest in the agricultural landscape of South America. We show that the spatial distribution of H. armigera mtDNA haplotypes and its inferred gene flow patterns in the southwestern region of South America exhibited signatures inconsistent with a single incursion hypothesis. Simulations on spatial distribution patterns show that the detection of rare and/or the absence of dominant mtDNA haplotypes in southern H. armigera populations are inconsistent with genetic signatures observed in northern and central Brazil. Incursions of H. armigera into the New World are therefore likely to have involved independent events in northern/central Brazil, and southern Brazil/Uruguay-Argentina-Paraguay. This study demonstrates the significant biosecurity challenges facing the South American continent, and highlights alternate pathways for introductions of alien species into the New World.

scholarly journals Multiple incursion pathways for Helicoverpa armigera in Brazil show its genetic diversity spreading in a connected world

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jonas Andre Arnemann ◽  
Stephen Roxburgh ◽  
Tom Walsh ◽  
Jerson Guedes ◽  
Karl Gordon ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Gene Flow ◽  
South America ◽  
New World ◽  
Flow Patterns ◽  
South American ◽  
Southern Brazil ◽  
American Continent ◽  
Central Brazil ◽  
South American Continent

AbstractThe Old World cotton bollworm Helicoverpa armigera was first detected in Brazil with subsequent reports from Paraguay, Argentina, Bolivia, and Uruguay. This pattern suggests that the H. armigera spread across the South American continent following incursions into northern/central Brazil, however, this hypothesis has not been tested. Here we compare northern and central Brazilian H. armigera mtDNA COI haplotypes with those from southern Brazil, Uruguay, Argentina, and Paraguay. We infer spatial genetic and gene flow patterns of this dispersive pest in the agricultural landscape of South America. We show that the spatial distribution of H. armigera mtDNA haplotypes and its inferred gene flow patterns in the southwestern region of South America exhibited signatures inconsistent with a single incursion hypothesis. Simulations on spatial distribution patterns show that the detection of rare and/or the absence of dominant mtDNA haplotypes in southern H. armigera populations are inconsistent with genetic signatures observed in northern and central Brazil. Incursions of H. armigera into the New World are therefore likely to have involved independent events in northern/central Brazil, and southern Brazil/Uruguay-Argentina-Paraguay. This study demonstrates the significant biosecurity challenges facing the South American continent, and highlights alternate pathways for introductions of alien species into the New World.

The American Proteaceae

1998 ◽  
Vol 11 (4) ◽  
pp. 287 ◽  
Author(s):  
Ghillean T. Prance ◽  
Vanessa Plana
Keyword(s):  
South America ◽  
Molecular Data ◽  
Central American ◽  
General Distribution ◽  
South American ◽  
Land Bridge ◽  
Eastern Brazil ◽  
The Family ◽  
Single Genus ◽  
Morphological And Molecular Data

The American Proteaceae are outliers from the main centres of diversity of the family in Australia and South Africa. There are about 83 species in eight genera which all belong to the monophyletic subfamily Grevilleoideae. Three genera, Embothrium, Oreocallis and Lomatia, are placed in the tribe Embothrieae (sensu Johnson and Briggs), four Euplassa, Gevuina, Panopsis and Roupala in the Macadamieae and the single genus Orites in the Oriteae. There are five genera endemic to America and three also have species in Australia and New Guinea (Gevuina, Lomatia and Orites). The Proteaceae appear to have arrived in South America via two routes. The larger genera Euplassa, Panopsis and Roupala, which are all endemic to America and have a general distribution in northern South America and south-eastern Brazil, are derived from Gondwanaland before it separated from South America. The remaining genera are distributed either in temperate South America or in the high Andes and appear to have arrived more recently via the Australia–Antarctica–South American connection. Three of these genera have species in both regions. The centres of species diversity of Euplassa, Panopsis and Roupala fall outside hypothesised forest refugia, indicating that they are not true rainforest species but species of seasonal habitats like those achieved at higher altitudes where they are commonly found. Two genera,Panopsis and Roupala, have reached Central America after the central American land bridge was formed six million years ago. The exact relationship to genera on other continents is still unclear and there is a need for a cladistic biogeographic analysis of the group based on both morphological and molecular data.

Abrupt variations in South American monsoon rainfall during the Holocene based on a speleothem record from central-eastern Brazil

Geology ◽  
2011 ◽  
Vol 39 (11) ◽  
pp. 1075-1078 ◽  
Author(s):  
N. M. Strikis ◽  
F. W. Cruz ◽  
H. Cheng ◽  
I. Karmann ◽  
R. L. Edwards ◽  
...  
Keyword(s):  
Monsoon Rainfall ◽  
South American ◽  
The Holocene ◽  
South American Monsoon ◽  
Eastern Brazil ◽  
Central Eastern

A clarification of the name Carex hypsipedos C.B.Clarke (Cyperaceae) and a new name for the South American Carex section Acrocystis taxon

Phytotaxa ◽  
2017 ◽  
Vol 291 (4) ◽  
pp. 287 ◽  
Author(s):  
D. B. POINDEXTER ◽  
M. ESCUDERO ◽  
P. JIMÉNEZ-MEJÍAS
Keyword(s):  
South America ◽  
Original Description ◽  
The Other ◽  
South American ◽  
The South ◽  
New Name ◽  
Additional Detail ◽  
Mixed Collection

In 1906, Clarke described C. hypsipedos based on specimens of Weberbauer 2617 and placed this species in subgenus Vignea. In 1909, Kükenthal also described the name C. umbellata var. depressa on the basis of the number Weberbauer 2617, a species attributed to section Acrocystis of subgenus Carex. Wheeler in 1988 also placed C. hypsipedos in section Acrocystis while reducing Kükenthal’s name to synonymy. During a recent herbarium survey, we studied syntypes corresponding to Weberbauer 2617 at B, F, G, and MOL. The study of these materials revealed important inconsistencies between the specimens and Clarke’s protologue and Wheeler’s study, suggesting that Weberbauer 2617 is a mixed collection of two different species. One plant conforms to Carex sect. Acrocystis, while the other bears resemblance to subgenus Vignea. Several salient characters distinguish these two taxa from each other, most notably including: stigmas 3 vs. stigmas 2, achenes trigonous vs. lenticular, and perigynium pubescent to puberulent vs. glabrous. Carex hypsipedos from Peru, corresponding to Clarke’s original description, is here lectotypified. The Carex sect. Acrocystis species is assigned a new name, Carex punicola, from Argentina, Bolivia, and Peru (South America). In addition to Wheeler’s (1988) observations, we here provide additional detail and illustration of this species. It is closely related to C. geophila, another American species in section Acrocystis.

New records of Neogene Xenarthra (Mammalia) from eastern Puna (Argentina): diversity and biochronology

2019 ◽  
Vol 93 (06) ◽  
pp. 1258-1275
Author(s):  
Sofía I. Quiñones ◽  
Ángel R. Miño-Boilini ◽  
Alfredo E. Zurita ◽  
Silvina A. Contreras ◽  
Carlos A. Luna ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
South America ◽  
Late Miocene ◽  
New Records ◽  
The Other ◽  
South American ◽  
Sister Clade ◽  
Cenozoic Era ◽  
Climatic Optimum ◽  
High Diversity

AbstractXenarthra is an endemic South American lineage of mammals, probably the sister clade of the other placental mammals. The oldest records of Xenarthra are from the latest Paleocene, although its current diversity is much lower than that recorded in some intervals of the Cenozoic Era. A new Neogene Xenarthra (Pilosa and Cingulata) assemblage from two localities of the Argentine Eastern Puna (Calahoyo and Casira) is described. The newly recorded taxa—Cingulata, Dasypodidae, Eutatini: Stenotatus sp. indet. and Eutatini indet., Euphractini: Macrochorobates scalabrinii (Moreno and Mercerat, 1891), and Tardigrada, Mylodontinae: cf. Simomylodon sp. indet. and Simomylodon cf. S. uccasamamensis Saint-André et al., 2010—and those already published from Calahoyo—Cingulata: Macrochorobates chapadmalensis (Ameghino, 1908), Eosclerocalyptus sp. indet., and Tardigrada, Megatheriidae: Pyramiodontherium bergi (Moreno and Mercerat, 1891)—suggest a middle–late Miocene age for the fossil-bearing levels. In Calahoyo, the presence of Stenotatus sp. indet., in addition to some rodents currently under study in the lower levels, suggest a closer similarity with the palaeofauna of Cerdas (southern Bolivia), probably involving the last part of the Miocene Climatic Optimum. The Xenarthra recorded in the middle and upper levels of Calahoyo and Casira suggest a late Miocene–Pliocene age. A comparative analysis between Calahoyo and Casira highlights the absence of Cingulata in the latter and a high diversity in the former. This situation probably indicates different paleoenvironmental conditions. Finally, we present the first certain record of the genus Simomylodon Saint-André et al., 2010 in Argentina, which includes the oldest record of dermal ossicles for sloths in South America.

scholarly journals Daily Precipitation Statistics for South America: An Intercomparison between NCEP Reanalyses and Observations

2011 ◽  
Vol 12 (1) ◽  
pp. 101-117 ◽  
Author(s):  
Viviane B. S. Silva ◽  
Vernon E. Kousky ◽  
R. Wayne Higgins
Keyword(s):  
South America ◽  
Large Scale ◽  
Atmospheric Model ◽  
Northeastern Brazil ◽  
South American ◽  
The South ◽  
Wet Season ◽  
Central Brazil ◽  
Monsoon System ◽  
Dry Bias

Abstract In this study, the authors document the extent to which the precipitation statistics of the new CFS reanalysis (CFSR) represent an improvement over the earlier reanalyses: the NCEP–NCAR reanalysis (R1) and the NCEP–DOE Second Atmospheric Model Intercomparison Project (AMIP-II) reanalysis (R2). An intercomparison between the CFSR, R1, R2, and observations over South America was made for the period 1979–2006. The CFSR shows notable improvements in the large-scale precipitation patterns compared with the previous reanalyses (R1 and R2). In spite of these improvements, the CFSR has substantial biases in intensity and frequency of occurrence of rainfall events. Over west-central Brazil, the core region of the South American monsoon system (SAMS), the CFSR displays a dry bias during the onset phase of the SAMS wet season and a wet bias during the peak and decay phases of the SAMS wet season. The CFSR also displays a dry bias along the South American coast near the mouth of the Amazon and along the east coast of northeastern Brazil. A wet bias exists in all seasons over southeast Brazil and over the Andes Mountains.

A morphometric evaluation of the subspecies of Fragaria chiloensis

1998 ◽  
Vol 76 (2) ◽  
pp. 290-297 ◽  
Author(s):  
Paul M Catling ◽  
Sue Porebski
Keyword(s):  
Discriminant Analysis ◽  
South America ◽  
North American ◽  
The Other ◽  
South American ◽  
Taxonomic Rank ◽  
Fragaria Chiloensis ◽  
America South ◽  
The Relationship ◽  
Morphometric Evaluation

To evaluate the relationship between the four subspecies of Fragaria chiloensis, 14 characters were measured in 95 plants. F ratios from ANOVA were used to determine and apply the optimal characters for subspecies separation. Discriminant analysis indicated that the Hawaiian ssp. sandwicensis was entirely distinct, differing from the other subspecies in having longer leaflets and longer hairs on the undersurface of the leaflets and more numerous leaflet veins. The South American and North American plants were significantly different but overlapped to a degree. The former differed primarily by having mostly 6-10 petals, instead of having 5-6 (rarely 7) petals. The two North American subspecies overlapped extensively and may be best transferred to a lower taxonomic rank. A key to the subspecies is included.Key words: Fragaria chiloensis, ssp. pacifica, ssp. lucida, ssp.sandwicensis, ssp. chiloensis, Rosaceae, strawberry, taxonomy, classification, morphology, North America, South America, Hawaii.

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