scholarly journals Deep Convection East of the Andes Cordillera: A Test Case Analysis of Airmass Origin

2008 ◽  
Vol 136 (6) ◽  
pp. 2201-2209 ◽  
Author(s):  
Hector Teitelbaum ◽  
Hervé Le Treut ◽  
Mohamed Moustaoui ◽  
Gustavo C. Cabrera ◽  
Guillermo Ibañez

Abstract Warm and moist air masses, required to generate deep convection east of the Andes Cordillera, are generally the result of humidity transport by the so-called low-level jet (LLJ). In this paper, it is shown from detailed test cases that the eastern part of the continent and the adjacent Atlantic Ocean may constitute another source of moist, warm air, which could be of potential importance even in the presence of a southerly LLJ. The position of the anticyclones crossing South America from the Pacific Ocean to the Atlantic Ocean appears to be a key factor affecting the origin of moisture over the continent. In particular, the LLJ may weaken and even change its direction when the eastern side of the South Pacific anticyclone crosses the mountains; this wind reversal is generally associated with deep convection suppression. Thus, as a South Pacific anticyclone crosses the continent more to the east and its western side reaches the east coast of South America, deep convection can reappear east of the Andes, over the Mendoza region, although the LLJ is frequently suppressed. This is associated with a transport of warm and moist air from Uruguay, southeast Brazil, or even directly from the Atlantic Ocean.

Author(s):  
Juan J. Armesto ◽  
Mary T. K. Arroyo

The Mediterranean-type environment of South America, broadly defined as the continental area characterized by winter rainfall and summer drought, is confined to a narrow band about 1,000 km long on the western side of the Andes in north-central Chile (Arroyo et al., 1995, 1999). Although much has been written about the climate, vegetation, and landscapes of this part of Chile, and comparisons have been drawn with California and other Mediterranean-type regions of the world (Parsons, 1976; Mooney, 1977; Rundel, 1981; Arroyo et al., 1995), a modern synthesis of information on the physical setting, regional biota, and historical development of ecosystems in central Chile has not been attempted. This chapter is intended to provide such an integrated picture, emphasizing those aspects most peculiar to the region. Since the earlier floristic work on the Chilean matorral (e.g. Mooney, 1977), the name given to the vegetation of central Chile, there is now a much greater appreciation of the geographic isolation and high levels of biological diversity and endemism in this region of South America (Arroyo and Cavieres, 1997; Villagrán, 1995; Arroyo et al., 1995, 1999). Because of the great richness and singularity of its terrestrial flora, this area of the continent is considered to be one of the world’s 25 hotspots in which to conserve global biodiversity (Arroyo et al., 1999; Myers et al., 2000). An analysis of the main features of the Mediterranean environment in South America should therefore address the causes of such high floristic richness, the nature of current threats to biodiversity, and the prospects for its conservation in the long-term. A discussion of conservation concerns closes the present chapter (but see also: Arroyo and Cavieres, 1997; and Arroyo et al., 1999). In view of the vast literature on the biota and physical setting of central Chile, this chapter adopts a selective approach, from a biogeographic perspective, of what we consider to be the most remarkable historical, physical, and ecological features of this environment, which in turn may explain its extraordinary richness in plants and animals. Mediterranean-type ecosystems occupy a narrow band along the western margin of South America, from 30 to 36°S in central Chile.


2020 ◽  
Vol 27 (3) ◽  
pp. 395-400
Author(s):  
Carlos Hernán Nivelo-Villavicencio ◽  
David C. Siddons ◽  
Pedro X. Astudillo ◽  
Javier Fernández de Córdova

The Vespertilionidae family is widely distributed in South America. In Ecuador, there are 20 species including Myotis riparius. The species has been recorded between 10 to 1240 m a.s.l. on the both eastern and western sides of the Andes cordillera. In this work we reported two new localities for southern Ecuador which include the highest records for the species and increasing in 1077 m the limit elevation previously known in Ecuador.


The Condor ◽  
2005 ◽  
Vol 107 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Marcelo Stucchi ◽  
Steven D. Emslie

AbstractWe report the oldest fossil condor (Vulturidae) from South America and the first from the Pisco Formation (14.0–2.0 Ma) of Peru, described herein as Perugyps diazi new genus and species. The Pisco Formation, exposed on the southern coast of Peru, has produced well-preserved and abundant marine and terrestrial vertebrate fossils from the late Miocene/early Pliocene (6.0–4.5 Ma) Montemar and Sacaco Sur localities, from where P. diazi was recovered. The new condor adds to our knowledge on the evolution and biogeographic distribution of New World vultures. The age of this new species supports the hypothesis that condors probably evolved in North America and entered South America by the late Miocene/early Pliocene. We believe it is likely that the first condors to reach South America probably did so via a coastal corridor along the western side of the Andes where they became part of the diverse coastal fauna in southern Peru.Un Nuevo Cóndor (Ciconiiformes, Vulturidae) del Mioceno Tardío-Plioceno Temprano de la Formación Pisco, PerúResumen. Se reporta el cóndor más antiguo de América del Sur y el primero para la Formación Pisco (14–2 Ma), y se describe como Perugyps diazi. De esta formación, situada en la costa sur del Perú, provienen gran cantidad de aves marinas en muy buen estado de conservación, en especial de los niveles Montemar y Sacaco Sur (Mioceno tardío/Plioceno temprano, 6.0–4.5 Ma), justamente de donde procede Perugyps. Este nuevo cóndor añade importante información sobre la evolución y distribución biogeográfica de estas aves, pues su edad apoya la hipótesis de que los cóndores probablemente evolucionaron en América del Norte y entraron a América del Sur entre el Mioceno tardío y el Plioceno temprano. Sugerimos que su llegada pudo realizarse por el corredor costero del lado occidental de los Andes, en donde pasaron a formar parte de la diversa fauna del sur del Perú.


2007 ◽  
Vol 135 (4) ◽  
pp. 1596-1613 ◽  
Author(s):  
RenéD. Garreaud ◽  
Humberto A. Fuenzalida

Abstract A cutoff low (COL) pressure system that occurred in March 2005 (late austral summer) over the subtropical southeast Pacific is examined by means of numerical simulations using the Weather and Research Forecasting (WRF) model. The episode exhibited typical features of COLs in this region, including its formation from an elongated northwest–southeast extratropical trough and subsequent intensification off the west coast of South America. During the developing stage, the cyclonic circulation did not extend into the lower troposphere and only upper-level, nonprecipitating clouds were observed at and around the system. When the COL reached the continent it produced moderate but unseasonal rainfall along the semiarid western slope of the Andes cordillera [summit level at ∼5000 m above sea level (ASL)] at the same time that the system experienced a rapid decay. The control simulation used full physics, full topography, and a single domain (54-km grid spacing) laterally forced by atmospheric reanalysis. Model results are in general agreement with upper-air, surface, and satellite observations, and allow a detailed description of the three-dimensional structure of the COL, as well as an evaluation of the vorticity and temperature budgets. A quasi-stationary, amplifying warm ridge over the South Pacific appears as the key precursor feature, in agreement with studies elsewhere. Once the COL formed, it drifted eastward mostly driven by vorticity advection induced by its own circulation, and there was close balance between vertical and horizontal temperature advection near its center. The jet streak along the COL’s periphery migrated from upstream of the COL axis, during the developing stage, to downstream later on. Four sensitivity experiments—reducing/removing topography, suppressing hydrometeors, and using an enlarged domain—were performed to assess the influence of the Andes, the importance of latent heat release, and the effect of the boundary conditions. Comparison among the control and sensitivity runs indicates that the COL formation occurs regardless of the presence of the Andes, and COL dissipation is mainly due to latent heat released in the deep clouds that form over the mountainous terrain. Nevertheless, the Andes cordillera delayed the COL demise by blocking the inflow of warm, moist air from the interior of the continent that otherwise would initiate deep convection in the region of ascending motion downstream of the COL.


Nematology ◽  
2010 ◽  
Vol 12 (2) ◽  
pp. 163-169 ◽  
Author(s):  
Eric Grenier ◽  
Sylvain Fournet ◽  
Eric Petit ◽  
Géraldine Anthoine

Abstract The cyst nematode, Globodera pallida, is a major pest of potato, a plant native to South America. To investigate its phylogeography, an extensive sampling survey was conducted in 2002 in Peru and has laid the foundations of the ancient evolutionary history of this nematode species. We argue that the uplift of the Andes Mountains has triggered a variety of adaptive biotic radiations for Solanaceous plant-parasitic nematodes and has represented a key factor for the evolution and specialisation of Globodera species. We discuss the consequences of the wide genetic diversity observed in South American populations on the efficiency and durability of potato resistance and also the reliability of current molecular identification tools for quarantine purposes. Finally, we emphasise the need to get a more in-depth taxonomic characterisation of some of these nematode populations, and to conduct more extensive sampling in South America, especially south of Lake Titicaca, in order to understand fully potato cyst nematode evolution and their adaptation to their host plants.


Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 637
Author(s):  
Mariacaterina Lianza ◽  
Ritchy Leroy ◽  
Carine Machado Rodrigues ◽  
Nicolas Borie ◽  
Charlotte Sayagh ◽  
...  

The role and importance of the identification of natural products are discussed in the perspective of the study of secondary metabolites. The rapid identification of already reported compounds, or structural dereplication, is recognized as a key element in natural product chemistry. The biological taxonomy of metabolite producing organisms, the knowledge of metabolite molecular structures, and the availability of metabolite spectroscopic signatures are considered as the three pillars of structural dereplication. The role and the construction of databases is illustrated by references to the KNApSAcK, UNPD, CSEARCH, and COCONUT databases, and by the importance of calculated taxonomic and spectroscopic data as substitutes for missing or lost original ones. Two NMR-based tools, the PNMRNP database that derives from UNPD, and KnapsackSearch, a database generator that provides taxonomically focused libraries of compounds, are proposed to the community of natural product chemists. The study of the alkaloids from Urceolina peruviana, a plant from the Andes used in traditional medicine for antibacterial and anticancer actions, has given the opportunity to test different approaches to dereplication, favoring the use of publicly available data sources.


The Condor ◽  
2021 ◽  
Author(s):  
Natália Stefanini Da Silveira ◽  
Maurício Humberto Vancine ◽  
Alex E Jahn ◽  
Marco Aurélio Pizo ◽  
Thadeu Sobral-Souza

Abstract Bird migration patterns are changing worldwide due to current global climate changes. Addressing the effects of such changes on the migration of birds in South America is particularly challenging because the details about how birds migrate within the Neotropics are generally not well understood. Here, we aim to infer the potential effects of future climate change on breeding and wintering areas of birds that migrate within South America by estimating the size and elevations of their future breeding and wintering areas. We used occurrence data from species distribution databases (VertNet and GBIF), published studies, and eBird for 3 thrush species (Turdidae; Turdus nigriceps, T. subalaris, and T. flavipes) that breed and winter in different regions of South America and built ecological niche models using ensemble forecasting approaches to infer current and future potential distributions throughout the breeding and wintering periods of each species. Our findings point to future shifts in wintering and breeding areas, mainly through elevational and longitudinal changes. Future breeding areas for T. nigriceps, which migrates along the Andes Mountains, will be displaced to the west, while breeding displacements to the east are expected for the other 2 species. An overall loss in the size of future wintering areas was also supported for 2 of the species, especially for T. subalaris, but an increase is anticipated for T. flavipes. Our results suggest that future climate change in South America will require that species shift their breeding and wintering areas to higher elevations in addition to changes in their latitudes and longitude. Our findings are the first to show how future climate change may affect migratory birds in South America throughout the year and suggest that even closely related migratory birds in South America will be affected in different ways, depending on the regions where they breed and overwinter.


Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Daniela Arenas-Viveros ◽  
Pamela Sánchez-Vendizú ◽  
Alan Giraldo ◽  
Jorge Salazar-Bravo

Abstract The systematics and taxonomy of the broadly distributed bats of the genus Cynomops has changed considerably in the last few years. Among the major changes, Cynomops abrasus was split into two species of large-bodied forms (Cynomops mastivus and C. abrasus) distributed east of the Andes. However, large Colombian specimens identified as C. abrasus from the western side of the Andes had yet to be included in any revisionary work. Phylogenetic analysis performed in this study, using mtDNA sequences (Cytochrome-b), revealed that these Colombian individuals are more closely related to Cynomops greenhalli. Morphological and molecular data allowed us to recognize populations from western Colombia, western Ecuador and northwestern Peru, as members of a new species of Cynomops. Characters that allow for its differentiation from C. greenhalli include a larger forearm, paler but more uniform ventral pelage, more globular braincase, and well-developed zygomatic processes of the maxilla (almost reaching the postorbital constriction). This study serves as another example of the importance of including multiple lines of evidence in the recognition of a new species. Given its rarity and the advanced transformation of its habitat, this new species is particularly important from a conservation perspective.


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