Systems In South America Research Articles

The dissolved chemical and isotopic signature downflow the confluence of two large rivers: The case of the Parana and Paraguay rivers

Summary The Parana River basin is one of the largest hydrological systems in South America (∼2.6 × 10 6 km 2 ). Downflow the confluence of tributaries, most large rivers exhibit transverse and longitudinal inhomogeneities that can be detected for tens or even hundreds of kilometers. Concordantly, a noticeable cross-sectional chemical asymmetry in the dissolved load was distinguished in the Middle Parana River, after the confluence of its main tributaries (i.e., the Paraguay and Upper Parana rivers). Water chemistry and isotopic signature in three cross-sections along the Middle Parana River, as well as from main and minor tributaries, and some deep (∼105 m bs) and shallow boreholes (∼15 m bs) located near both river banks, were analyzed in order to define the extent of mixing and identify possible contributions from groundwater discharges. Downflow the confluence of the Upper Parana and Paraguay rivers a chemical and isotopic asymmetry was observed, mainly through the values of EC, major ions (Ca 2+ , Na + , Mg 2+ , Cl − and SO 4 2 − ), some trace elements (Fe, U, Th, Ba, Sr, As and REE) and stable isotopes (δ 18 O and δ 2 H). Toward its western margin, higher elemental concentrations which resembled that of the Paraguay River were measured, whereas at the eastern border, waters were more diluted and preserved the chemical signature of the Upper Parana River. This variability remained detectable at least until ∼225 km downflow the confluence, where differences between western and eastern margins were less evident. At ∼580 km downflow the confluence, a slight inversion in the transverse chemical asymmetry was observed. This trend switch can be the result of the input of solutes from minor tributaries that reach the main channel from the East and/or may be due to higher groundwater discharges from the East bank. A mass balance model was applied, as a first approach, to estimate the groundwater inflow using the geochemical tracer 222 Rn. The results indicate that groundwater contributions represent between ∼0.5% and 6% of the total water inputs to the Middle Parana River under baseflow conditions. This implies that the chemical asymmetry in the Middle Parana River is mostly due to the incomplete mixing of the main tributaries. Though the influence of groundwater is not a determining factor in the chemical variability of the river, it may partially explain the higher concentrations of some trace elements found in the eastern margin ∼580 km downflow the confluence.

State of emergency medicine in Colombia.

Colombia is an upper-middle-income country with a population of 45 million people and one of the best national healthcare and medical education systems in South America. However, its widely diverse and difficult terrains hinder healthcare delivery to rural areas, creating disparities in healthcare access and outcomes between the urban and rural settings. Currently, emergency medical care is overwhelmingly provided by general practitioners without residency training, who obtain specialty consultations based on the medical/surgical condition identified. A few emergency medicine (EM) residency programs have sprouted over the last two decades in renowned academic institutions in the largest cities, producing high-quality EM specialists. With the establishment of EM as a specialty in 2005 and increasing recognition of the specialty, there has been an increasing demand for EM specialists in cities, which is only slowly being met by the current residencies. The critical challenges for EM in Colombia are both, establishing itself as a well-recognized specialty - by increasing academic production and reaching a critical mass of and unity among EM specialists - and providing the highest quality and safest emergency care to the people of Colombia - by improving capacity both in emergency departments and in the regional and national emergency response systems. Historically, the establishment of EM as a strongly organized specialty in other countries has spanned decades (e.g., the United States), and Colombia has been making significant progress in a similar trajectory.

Reformas de los sistemas de salud en Sudamérica: una oportunidad para UNASUR

Health systems in South America still support segmentation, privatization and fragmentation. Health reforms of the structural adjustment programs in the 1980s and 1990s in South America followed different purposes and strategies ranging from privatization, commodification and state intervention for the implementation of a national public health service with universal access as a right of the citizens. Since the 2000s, many countries have expanded social policies, reduced poverty and social inequalities, and improved access to healthcare. This article proposes to discuss the health systems in South America from historical and political backgrounds, and the progress from the reforms in the last three decades. It also presents the three paradigmatic models of reform and their evolution, as well as the contrasts between universal coverage and universal systems. Finally, it presents current strengths and weaknesses of the twelve South American health systems as well as current opportunities and challenges in health for UNASUR.

The contribution of ethnobotany and experimental archaeology to interpretation of ancient food processing: methodological proposals based on the discussion of several case studies on Prosopis spp., Chenopodium spp. and Cucurbita spp. from Argentina

The purpose of this paper is to discuss recent methodological advances in Argentinean archaeobotany that incorporate the use of ethnobotany as an ethnoarchaeological tool for interpreting ancient food systems in South America. This is an integrative paper that takes into account both published and unpublished results. The role of ethnobotany is examined with reference to ethnobotanical and experimental food processing studies on Prosopis, a wild food plant, and two cultivated ones Chenopodium quinoa and Cucurbita spp., followed by laboratory examinations with microscopy to identify diagnostic changes in plant morphology and anatomy. Experimental materials are then compared with archaeological specimens to identify different types of ancient food processing, and to make inferences about prehistoric post-harvest systems. We demonstrated that: (a) it was critical for our food processing studies to achieve the best taxonomical identification resolution that the plant remains allow; (b) a multi-proxy approach was highly advantageous; (c) ethnobotanical data were crucial to identify food processing pathways of individual plants and combinations of them; (d) the understanding of commensality in the wider sense of the term allows us to determine food patterns both in domestic and funerary contexts. These investigations, the first ones of this type in Argentina, constitute a qualitative step in the methodology for this country because they expand our abilities to interpret the nature of routine plant processing from archaeobotanical assemblages, and they are also a substantial contribution to the development of our discipline in general because the taxa discussed in this paper are distributed throughout South America, as well as in other parts of the world.

Establishing evidence of a non-native species Pachyurus bonariensis Steindachner, 1879 (Perciformes, Sciaenidae) in Mirim Lagoon, Rio Grande do Sul (Brazil)

The La Plata croaker (Pachyurus bonariensis) family Sciaenidae, is a small (< 23 cm) benthopelagic fish that originated in the Parana- Paraguay-Uruguay river systems in South America. Its first record in the Patos Lagoon drainage area, Rio Grande do Sul (Brazil) occurred in 2001. This research reports for the first time, the occurrence of both juvenile and adult specimens of P. bonariensis in the Sao Goncalo Channel (a 75 km long waterway between Patos and Mirim lagoon) and in the Mirim Lagoon, in 2005 and 2007 respectively. A total of 434 gonads were analyzed histologically from specimens captured by artisanal fishermen at Capilha, Mirim Lagoon between 2008 and 2010. Gonadal development was observed and described. Pachyurus bonariensis probably dispersed from northern Patos Lagoon in 2001 to the Sao Goncalo Channel by 2005. The occurrence of adults in limnic waters in the Sao Goncalo Channel and further south in the Mirim Lagoon in 2007, confirm that P. bonariensis is now an established species in Mirim Lagoon and could become a commercially important species to the artisanal fishermen of the area. Likewise at the limnetic northern parts of Patos Lagoon, P. bonariensis is now abundant at Mirin Lagoon and the ecological impacts of this range extension must be investigated.

Influence of Lime and Gypsum on Growth and Yield of Upland Rice and Changes in Soil Chemical Properties

Upland rice is an important crop in the cropping systems of South America, including Brazil. Two greenhouse experiments were conducted to determine influence of lime and gypsum on yield and yield components of upland rice and changes in the chemical properties of an Oxisol. The lime rates used were 0, 0.71, 1.42, 2.14, 2.85, and 4.28 g kg−1 soil. The gypsum rates were 0, 0.28, 0.57, 1.14, 1.71, and 2.28 g kg−1. Lime as well as gypsum significantly increased plant height, straw and grain yield, and panicle density in a quadratic fashion. Adequate lime and gypsum rates for maximum grain yield were 1.11 g kg−1 and 1.13 g kg−1, respectively. Plant height, straw yield, and panicle density were positively related to grain yield. Lime as well as gypsum application significantly changed extractable calcium (Ca), magnesium (Mg), hydrogen (H)+aluminum (Al), base saturation, and effective cation exchange capacity. In addition, liming also significantly increased pH, extractable phosphorus (P) and potassium (K), calcium saturation, magnesium saturation, and potassium saturation. Optimum acidity indices for the grain yield of upland rice were pH 6.0, Ca 1.7 cmolc kg−1, base saturation 60%, and calcium saturation 47%. In addition, upland rice can tolerate 42% of acidity saturation.

Phylogenetics ofEscallonia(Escalloniaceae) based on plastid DNA sequence data

Fil: Sede, Silvana Mabel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Botanica Darwinion. Academia Nacional de Ciencias Exactas, Fisicas y Naturales. Instituto de Botanica Darwinion; Argentina

Critical success factors when going global: New Zealand farming systems in South America

New Zealanders are being encouraged to find offshore investment opportunities where using a New Zealand farming system will give a competitive advantage. This analysis investigated three pasture-based dairying operations in South America. A comparison of the three cases against a framework for dairying success identified in the literature enabled critical success factors to be identified. These included infrastructure, human and animal capital, and an understanding of culture. Keywords: Capital, culture, infrastructure, labour

The coexistence of peace and conflict in South America: toward a new conceptualization of types of peace

South America's predominant democratic regimes and its increasing interdependence on regional trade have not precluded the emergence of militarized crises between Colombia and Venezuela or the revival of boundary claims between Chile and Peru. This way, how can we characterize a zone that, in spite of its flourishing democracy and dense economic ties, remain involved in territorial disputes for whose resolution the use of force has not yet been discarded? This article contends that existing classifications of zones of peace are not adequate to explain this unusual coexistence. Thus, its main purpose is to develop a new analytical category of regional peace for assessing this phenomenon: the hybrid peace. It aims to research the evolution of security systems in South America during the previous century and build a new, threefold classification of peace zones: negative peace zones, hybrid peace zones, and positive peace zones.

Population structure and gene flow of the yellow anaconda (Eunectes notaeus) in northern Argentina.

Yellow anacondas (Eunectes notaeus) are large, semiaquatic boid snakes found in wetland systems in South America. These snakes are commercially harvested under a sustainable management plan in Argentina, so information regarding population structuring can be helpful for determination of management units. We evaluated genetic structure and migration using partial sequences from the mitochondrial control region and mitochondrial genes cyt-b and ND4 for 183 samples collected within northern Argentina. A group of landscape features and environmental variables including several treatments of temperature and precipitation were explored as potential drivers of observed genetic patterns. We found significant population structure between most putative population comparisons and bidirectional but asymmetric migration in several cases. The configuration of rivers and wetlands was found to be significantly associated with yellow anaconda population structure (IBD), and important for gene flow, although genetic distances were not significantly correlated with the environmental variables used here. More in-depth analyses of environmental data may be needed to fully understand the importance of environmental conditions on population structure and migration. These analyses indicate that our putative populations are demographically distinct and should be treated as such in Argentina's management plan for the harvesting of yellow anacondas.

Integrated coastal zone management in South America: A look at three contrasting systems

The management of coastal systems where overlapping economic interests compete for the same resources make the use of integrated approaches indispensable. The Integrated Coastal Zone Management (ICZM) focuses mainly on three major goals: (1) overcoming the conflicts associated with the sectorial management, (2) preserving the productivity and biological diversity of coastal systems, and (3) promoting and equitable and sustainable allocation of coastal resources. The DPSIR (Drivers-Pressures-State-Impact-Responses) framework is a common tool that allows the description of environmental problems by defining the relationships between anthropogenic activities and the environment. In this context, the use of numerical models as integrative tools in ICZM has grown significantly over the years.This work focused on three estuarine systems in South America: Santos estuary (Brazil, 24° S) and Bahía Blanca estuary (Argentina, 39° S) in the Atlantic coast and Aysén fjord (Chile, 45°S) in the Pacific coast. These estuaries differ significantly in their physical, chemical and biological conditions, as well as on their socio-economic settings and human-related problems. Numerical models have been used to study the relation between the pressures derived from human activities and their impact on the state of each system.The results presents a contribute to increase the scientific knowledge needed to support the implementation of local legislations and policies, to assess different scenarios of coastal activities and sources use, to support management decisions and, ultimately, to promote sustainable of coastal resources.

Relationships between the spatial distribution of oligochaetes (Annelida, Clitellata) and environmental variables in a temperate estuary system of South America (Río de la Plata, Argentina)

The oligochaete assemblage on the Argentine coast of the Río de la Plata estuary was sampled seasonally within environments having different types of disturbances. Three habitats were sampled: sediments free of vegetation, sediments within bullrush stands and substrates with Limnoperna fortunei. The species richness, evenness and Shannon–Wiener diversity values were different among those habitats. The only dominant species (according to the Kownacki index) was Nais variabilis. Mean density values varied between 400 and 199,500 ind./m2. Organic matter, ammonium and phosphates correlated positively with the mean oligochaete abundance, but not with the granulometry. Physicochemical variables and nutrient levels were measured and their relation to the sampling sites assessed through a principal component analysis (41.8% cumulative variance). The canonical correspondence analysis (41.2% cumulative variance) indicated that the oligochaetes distributed along both a eutrophication–pollution gradient and a turbidity–conductivity gradient. These results would be useful for assessing the ecological status of estuaries for a subsequent implementation of appropriate sustainability-management policies.

Evaluation of mesoscale convective systems in South America using multiple satellite products and an object-based approach

[1] In this study, an object-based verification method was used to reveal the existence of systematic errors in three satellite precipitation products: Tropical Rainfall Measurement Mission (TRMM), Climate Prediction Center Morphing Technique (CMORPH), and Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Networks (PERSIANN). Mesoscale convective systems (MCSs) for the austral summer 2002–2003 in the La Plata river basin, southeastern South America, were analyzed with the Contiguous Rain Area (CRA) method. Errors in storms intensity, volume, and spatial location were evaluated. A macroscale hydrological model was used to assess the impact of spatially shifted precipitation on streamflows simulations. PERSIANN underestimated the observed average rainfall rate and maximum rainfall consistent with the detection of storm areas systematically larger than observed. CMORPH overestimated the average rainfall rate while the maximum rainfall was slightly underestimated. TRMM average rainfall rate and rainfall volume correlated extremely well with ground observations whereas the maximum rainfall was systematically overestimated suggesting deficiencies in the bias correction procedure to filter noisy measurements. The preferential direction of error displacement in satellite-estimated MCSs was in the east-west direction for CMORPH and TRMM. Discrepancies in the fine structure of the storms dominated the error decomposition of all satellite products. Errors in the spatial location of the systems influenced the magnitude of simulated peaks but did not have a significant impact on the timing indicating that the system's response to precipitation was mitigating the effect of the errors.

Physical controls on carbon dioxide transfer velocity and flux in low-gradient river systems and implications for regional carbon budgets

[1] Outgassing of carbon dioxide (CO2) from rivers and streams to the atmosphere is a major loss term in the coupled terrestrial-aquatic carbon cycle of major low-gradient river systems (the term “river system” encompasses the rivers and streams of all sizes that compose the drainage network in a river basin). However, the magnitude and controls on this important carbon flux are not well quantified. We measured carbon dioxide flux rates (FCO2), gas transfer velocity (k), and partial pressures (pCO2) in rivers and streams of the Amazon and Mekong river systems in South America and Southeast Asia, respectively. FCO2 and k values were significantly higher in small rivers and streams (channels 100 m wide). Small rivers and streams also had substantially higher variability in k values than large rivers. Observed FCO2 and k values suggest that previous estimates of basinwide CO2 evasion from tropical rivers and wetlands have been conservative and are likely to be revised upward substantially in the future. Data from the present study combined with data compiled from the literature collectively suggest that the physical control of gas exchange velocities and fluxes in low-gradient river systems makes a transition from the dominance of wind control at the largest spatial scales (in estuaries and river mainstems) toward increasing importance of water current velocity and depth at progressively smaller channel dimensions upstream. These results highlight the importance of incorporating scale-appropriate k values into basinwide models of whole ecosystem carbon balance.

Hierarchy, symmetry, and the xavante spiritual life cycle

Xavante society, well-known for its dual structural aspects, provides the best documented example of a formal age-group system in South America. Although the basic features of the Xavante secular age-group system were previously described, a second age-group system in the spiritual domain is presented here for the first time. In this paper, I describe the Xavante spiritual life cycle, including a structural dynamic whereby age sets pass through age grades in alternate fashion, allocating them between two moieties. That basic morphology is shared with the secular age-group system and attests to a Xavante logic of hierarchy and symmetry as mutually constructed and non-contradictory. Interactions between the spiritual and secular age-group systems manifest in the daily experience of spiritual participants in ways that suggest plurality and contingency are essential features of Xavante social organization.

Current status of adoption of no-till farming in the world and some of its main benefits.

In 1999 no-tillage farming, synonymous of zero tillage farming or conservation agriculture, was adopted on about 45 million ha world wide, growing to 72 million ha in 2003 and to 111 million ha in 2009, corresponding to an growth rate of 6 million ha per annum. Fastest adoption rates have been experienced in South America where some countries are using no-tillage farming on about 70% of the total cultivated area. Opposite to countries like the USA where often fields under no-tillage farming are tilled every now and then, more than two thirds of the area under no-tillage systems in South America is permanently not tilled; in other words once adopted, the soil is never tilled again. The spread of no-tillage systems on more than 110 million ha world-wide shows the great adaptability of the systems to all kinds of climates, soils and cropping conditions. No-tillage is now being practiced from the artic circle over the tropics to about 50o latitude south, from sea level to 3 , 000 m altitude, from extremely rainy areas with 2 , 500 mm a year to extremely dry conditions with 250 mm a year. No-till farming offers a way of optimizing productivity and ecosystem services, offering a wide range of economic, environmental and social benefits to the producer and to the society. At the same time, no-till farming is enabling agriculture to respond to some of the global challenges associated with climate change, land and environmental degradation, and increasing cost of food, energy and production inputs. The wide recognition of no-till farming as a truly sustainable system should ensure the spread of the no-till technology and the associated practices of organic soil cover and crop rotation, as soon as the barriers to its adoption have been overcome, to areas where adoption is currently still low. The widespread adoption globally also shows that no-tillage farming cannot any more be considered a temporary fashion or a craze; instead largely through farmers’ own effort, the system has established itself as a farming practice and a different way of thinking about sustainable agro-ecosystem management that can no longer be ignored by scientists, academics, extension workers, farmers at large as well as equipment and machine manufacturers and politicians. Keywords: w orld-wide no-till adoption , zero tillage adoption , conservation agriculture, soil health, climate change, ecosystem services DOI: 10.3965/j.issn.1934-6344.20 1 0.0 1 .0-0 Citation: Rolf D erpsch , Theodor F riedrich , Amir K assam, Li H ongwen . Current status of adoption of no-till farming in the world and some of its main benefits . Int J Agric & Biol Eng, 20 1 0; 3 ( 1 ): <span style=line-height: 140%; font-family:

Hypercapnic Acidosis Reduces Contractile Function in the Ventricle of the Armored Catfish,Pterygoplichthys pardalis

The armored catfish, Pterygoplichthys pardalis (formerly Liposarcus pardalis), is a freshwater, facultative air-breathing teleost that experiences seasonal hypercapnia in the water systems of South America. We studied the tolerance of the P. pardalis heart to hypercapnic acidosis using an isolated ventricular muscle strip preparation. Force generation and kinetic variables were examined across a range of contraction frequencies under normocapnic and hypercapnic conditions in the absence and presence of sarcoplasmic reticulum (SR) inhibitors. Pterygoplichthys pardalis ventricle exhibited robust contractile force, on par with athletic fish species such as trout and tuna and a relatively flat force-frequency relationship between 0.2 and 1.5 Hz under normocapnic conditions (1% CO2, pH 7.78 +/- 0.02). Hypercapnic acidosis (7.5% CO2, pH 7.78 +/- 0.03) did not alter the shape of the force-frequency response but reduced force by approximately 50% across all frequencies tested, with only partial recovery upon return to normocapnic conditions. A subsequent and more severe acidotic challenge (15% CO2, pH 6.77 +/- 0.05) caused an additional 20% decrease in force. Force recovered to the level at which it had stablized after the first hypercapnic insult. SR inhibition had no steady state effect on force production at 0.2 Hz but resulted in a negative force-frequency relationship, suggesting that SR Ca2+ is recruited to a greater extent at high contraction frequencies. Surprisingly, SR-inhibited muscle was more resistant to hypercapnic acidosis (force decreased by approximately 40% across all frequencies) and displayed improved recovery upon return to normocapnic conditions. The significance of this latter finding is not clear. In aggregate, our results demonstrate robust contractile force, which extends across a range of frequencies and appears to be supported by SR Ca2+ cycling. Hypercapnic acidosis reduced contractile force but may provide preconditioning-like protection from subsequent insults.

A phylogenetic and morphologic context for the radiation of an endemic fauna in a long-lived lake: Corbulidae (Bivalvia; Myoida) in the Miocene Pebas Formation of western Amazonia

The Corbulidae are one of a handful of a primarily marine bivalve clades that exhibit a remarkable radiation, marked by increased species richness and divergent morphologies, within a long-lived lake. For corbulids, this diversification occurred within the lower to middle Miocene Pebas Formation of western Amazonia. Only one taxon associated with this radiation (Anticorbula) remains extant. We conducted a series of phylogenetic analyses to characterize diversification of Corbulidae within the Pebas Formation and relate that diversification to geologically older freshwater corbulids from the Paleocene Fort Union Formation of the northern Great Plains (United States). We used these results, as well as a quantitative examination of morphospace occupation, to infer whether Pebasian corbulids represent a true species flock, and whether the lacustrine system represented by the Pebas Formation represents a cradle of, or reservoir for, freshwater corbulid diversity. We conducted two sets of phylogenetic analyses using shell morphology characters. A genus-level data set incorporated type species of freshwater corbulid genera, any Paleocene representatives of these genera, and selected brackish and marine corbulid genera. A species-level analysis added all described freshwater corbulid taxa to the genus-level matrix. Our results were highly resolved (few most-parsimonious trees), but not particularly robust (low branch support). For the genus-level matrix, we used a taxon jackknife procedure to explore the effects of taxon sampling on tree stability and topology. Jackknife results recover a subclade of freshwater taxa (including both Anticorbula and Pachydon species and the Paleocene Ostomya sp.) in 92.4% of trees, although placement of this subclade across the ingroup varies, as do the topologic positions of other freshwater species. Freshwater and marine corbulids also are morphologically distinct from each other, a factor that likely reduced the robustness of our phylogenetic results. By combining these results with paleoecologic, stratigraphic, and morphologic data, we infer that freshwater corbulids arose once within the family, prior to the Cenozoic, with three distinct freshwater lineages present at their first appearance in the late Paleocene of North America. Within the Miocene Pebas system of South America, we reconstruct supralimital morphologic evolution within three lineages as freshwater taxa became variously adapted to the fluid, dysoxic muds characterizing lake-bottom facies representative of the Pebas lacustrine system. In addition, corbulids apparently successfully coped with high predation pressures from co-occurring shell-crushing predators. Finally, we consider that freshwater Corbulidae were primarily fluvial taxa throughout their geologic history, with a relatively ephemeral radiation within the Pebasian lake system, thus making the Pebasian system a cradle of diversity for several corbulid lineages.

New perspectives on the synoptic and mesoscale structure of Hurricane Catarina

This work explores in detail synoptic and mesoscale features of Hurricane Catarina during its life cycle from a decaying baroclinic wave to a tropical depression that underwent tropical transition (TT) and finally to a Category 2 hurricane at landfall over Santa Catarina State coast, southern Brazil. This unique system caused 11 deaths mostly off the Brazilian coast and an estimated half billion dollars in damage in a matter of a few hours on 28 March 2004. Although the closest meteorological station available was tens of kilometres away from the eye, in situ meteorological measurements provided by a work-team sent to the area where the eye made landfall unequivocally reproduces the tropical signature with category 2 strength, adding to previous analysis where this data was not available. Further analyses are based mostly on remote sensing data available at the time of the event. A classic dipole blocking set synoptic conditions for Hurricane Catarina to develop, dynamically contributing to the low wind shear observed. On the other hand, on its westward transit, large scale subsidence limited its strength and vertical development. Catarina had relatively cool SST conditions, but this was mitigated by favourable air–sea fluxes leading to latent heat release-driven processes during the mature phase. The ocean's dynamic topography also suggested the presence of nearby warm core rings which may have facilitated the transition and post-transition intensification. Since there were no records of such a system at least in the past 30 years and given that SSTs were generally below 26 °C and vertical shear was usually strong, despite all satellite data available, the system was initially classified as an extratropical cyclone. Here we hypothesise that this categorization was based on inadequate regional scale model outputs which did not account for the importance of the latent heat fluxes over the ocean. Hurricane Catarina represents a dramatic event on weather systems in South America. It has attracted attention worldwide and poses questions as whether or not it is a symptom of global warming.

Relação dos sistemas de monção com as variabilidades tropical interanual e multi-decenal

A variabilidade da circulação tropical, com ênfase nos sistemas monçônicos, é examinada usando diversas variáveis para o período de 1948-1999. A componente monçônica do potencial de velocidade em 200 hPa (χ-transiente), o desvio da média anual do desvio da média zonal, é o parâmetro chave usado para obter os modos monçônicos. A análise de Funções Ortogonais Empíricas (EOF) do χ-transiente fornece dois modos separados. O primeiro modo descreve a variabilidade multi-decenal dos sistemas monçônicos da América do Sul e do Pacífico oeste. Esse modo, chamado monçônico multi-decenal (MMD), ocorre por todo o ano e contém a variabilidade multi-decenal relacionada à dinâmica da Oscilação Decenal do Pacífico (ODP). O segundo modo descreve as variações interanuais opostas entre a Ásia, África e oceano Índico e a região do oeste dos Estados Unidos, México e Pacífico leste. Esse modo, chamado modo interanual (MIA) apresenta algumas similaridades com o modo tropical interanual El Niño - Oscilação Sul. Alguns aspectos desses modos, incluindo sua circulação e características termodinâmicas são discutidas aqui. Finalmente, índices baseados nos padrões das configurações espaciais desses modos são construídos. A eficiência desses índices para fins de monitoramento é analisada. Logo, trata-se de um novo aspecto não proposto em trabalhos anteriores.