scholarly journals Severe Weather Events over Southeastern Brazil during the 2016 Dry Season

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Amanda Rehbein ◽  
Lívia Márcia Mosso Dutra ◽  
Tercio Ambrizzi ◽  
Rosmeri Porfírio da Rocha ◽  
Michelle Simões Reboita ◽  
...  

Southeastern Brazil is the most populated and economically developed region of this country. Its climate consists of two distinct seasons: the dry season, extending from April to September, the precipitation is significantly reduced in comparison to that of the wet season, which extends from October to March. However, during nine days of the 2016 dry season, successive convective systems were associated with atypical precipitation events, tornadoes and at least one microburst over the southern part of this region. These events led to flooding, damages to buildings, shortages of electricity and water in several places, many injuries, and two documented deaths. The present study investigates the synoptic and dynamical features related to these anomalous events. The convective systems were embedded in an unstable environment with intense low-level jet flow and strong wind shear and were supported by a sequence of extratropical cyclones occurring over the Southwest Atlantic Ocean. These features were intensified by the Madden–Julian oscillation (MJO) in its phase 8 and by intense negative values of the Pacific South America (PSA) 2 mode.

2008 ◽  
Vol 25 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Carlos Henrique de Freitas ◽  
Eleonore Z. F. Setz ◽  
Alba R. B. Araújo ◽  
Nivar Gobbi

Capuchin monkeys occupy a wide range of habitats where they feed on fruits, arthropods, and vertebrates. Their large home ranges (80-900 ha) suggest that living in forest fragments may challenge their adaptability. We identified and quantified the main food items of Cebus libidinosus Spix, 1823 in forests fragments (100 ha) in southeastern Brazil. We recorded the feeding activities of two groups using scan sampling over a 13-month period. The diet was composed of fruits, crops, animal prey, seeds, plant matter and undetermined. Fruit was eaten more in the wet season than in the dry season, and maize and sugar cane consumption peaked in the early dry season. The proportion of fruit in the diet was positively correlated with fruiting intensity of zoochorous trees. The plant diet included 54 species, with maize, Rhamnidium elaeocarpus, Acrocomia aculeata, Guazuma ulmifolia and Cariniana, being most important. Although dietary composition and diversity were similar to capuchins in larger forest fragments, feeding on crops attained higher percentages at times when zoochorous fruit production was low in fragments.


2013 ◽  
Vol 13 (1) ◽  
pp. 70-73 ◽  
Author(s):  
Frederico Alves D'Avila ◽  
Almério de Castro Gomes

A two and a half year survey was conducted at a dam in southeastern Brazil. Shannon Traps were used for sampling. Kruskal-Wallis test showed little relation between rainfall and abundance. The data clearly show three abundance peaks, all of them in the end of the dry season, in consonance with the scarce literature existent. Although Kruskal-Wallis Test did not find a clear preference for the dry season, Pairwise Wilcoxon Rank Test revealed a significant difference between Fall and Spring samples. Ma. titillans population had a peak on late winter/early spring, close to the begin of wet season.


Sociobiology ◽  
2018 ◽  
Vol 65 (4) ◽  
pp. 612 ◽  
Author(s):  
Marcelita França Marques ◽  
Mariana Scaramussa Deprá ◽  
Maria Cristina Gaglianone

Studies on bee-plant interactions are relevant to the understanding of temporal patterns in neotropical communities. In isolated habitats such as inselbergs little is yet known about the temporal dynamics in the availability of fl oral resources and interacting bee. In the present study, the objective is to verify the eff ect of seasonality on the bee-plant interaction in an Atlantic Forest inselberg in southeastern Brazil. The bees were sampled monthly in the dry (April/2008-September/2008) and wet seasons (October/2008-March/2009) using an entomological net. A total of 322 bees of 33 species were captured on fl owers of 34 species of plants during the year. Bees richness was similar between seasons (22 species in the wet season and 21 in the dry season), but abundance was higher in the wet season (60% of individuals) and higher diversity occurred in the dry season. Augochloropsis sp1 were the most abundant species and visited the largest number of plant species at each season. In the interaction network, plants with the highest degree were distinct between the seasons. The number of possible interactions was higher in the dry season compared to the wet season and connectance was similar; nestedness however varied between the seasons. The composition of plant and bees species was distinct between the seasons, as well as the interactions between them, mainly due to the alteration in the composition of the plant species and the change in the choice of the bees for the floral resources between the seasons.


2016 ◽  
Vol 16 (22) ◽  
pp. 14249-14264 ◽  
Author(s):  
Shuaiqi Tang ◽  
Shaocheng Xie ◽  
Yunyan Zhang ◽  
Minghua Zhang ◽  
Courtney Schumacher ◽  
...  

Abstract. This study describes the characteristics of large-scale vertical velocity, apparent heating source (Q1) and apparent moisture sink (Q2) profiles associated with seasonal and diurnal variations of convective systems observed during the two intensive operational periods (IOPs) that were conducted from 15 February to 26 March 2014 (wet season) and from 1 September to 10 October 2014 (dry season) near Manaus, Brazil, during the Green Ocean Amazon (GoAmazon2014/5) experiment. The derived large-scale fields have large diurnal variations according to convective activity in the GoAmazon region and the morning profiles show distinct differences between the dry and wet seasons. In the wet season, propagating convective systems originating far from the GoAmazon region are often seen in the early morning, while in the dry season they are rarely observed. Afternoon convective systems due to solar heating are frequently seen in both seasons. Accordingly, in the morning, there is strong upward motion and associated heating and drying throughout the entire troposphere in the wet season, which is limited to lower levels in the dry season. In the afternoon, both seasons exhibit weak heating and strong moistening in the boundary layer related to the vertical convergence of eddy fluxes. A set of case studies of three typical types of convective systems occurring in Amazonia – i.e., locally occurring systems, coastal-occurring systems and basin-occurring systems – is also conducted to investigate the variability of the large-scale environment with different types of convective systems.


Author(s):  
Waldilene Correa ◽  
Sueli Pereira ◽  
Joaquim Ernesto Bernardes ◽  
Paulo Ricardo Pereira

Groundwater-Surface water interactions in alluvial plains facing morphological features are the subject of the study. Considered transitions zones, alluvial plains have different morphological features interfering with groundwater flow and hydrochemistry. The alluvial plain of Mogi Guaçu river (southeastern Brazil) presented topography-controlled groundwater flow, nevertheless, natural levees, wet fields, oxbow lakes, and abandoned meanders can control local flow and interfere in discharges points of the main river. Two sampling water campaigns were done in the dry and wet season for physicochemical and natural isotopes analysis, collecting in total 44 groundwaters samples from monitoring wells and eight water samples from the river, creek, and lake. The groundwaters in wet fields and terraces, and surface waters from creek and lake presented low mineralization (EC from 8 to 37 μS.cm), pH acidic (4.98 to 5.8), and essentially Ca and Na-HCO composition. River waters samples presented pH between 5.92 e 7.69 (acidic in the rainy season and basic in the dry season), and EC from 24.2 and 181.1 μS/cm (lower values in the wet season), Na-HCO and Na-HCO-SO (dry season) and Ca-HCO and Na-HCO (rainy season) compositions. In dry season groundwaters composition showed evolution from sodium mixed (SO – HCO) to bicarbonate waters and higher mineralization; in wet season waters varied from Ca to Na-HCO composition and low mineralization, denoting dilution due to rainwater infiltration. Closer to the river margins, in abandoned meanders and oxbows, the groundwaters have increased values of EC and major ions indicating GW-SW mixtures, and effluent-influent changes (descendent and ascendent flux) in wet and dry seasons, respectively. Natural isotopes in groundwaters imply meteoric origin, without evaporation during recharge and high d-excess can be influenced by continental air masses and Amazonia Basin low-level jet. Shallow water table, permeable silty-sand material of vadose zone, flat terrain, and pristine conditions can contribute to direct infiltration of rainwaters, recharging the shallow aquifer.


2016 ◽  
Author(s):  
Shuaiqi Tang ◽  
Shaocheng Xie ◽  
Yunyan Zhang ◽  
Minghua Zhang ◽  
Courtney Schumacher ◽  
...  

Abstract. This study describes the characteristics of large-scale vertical velocity, apparent heating source (Q1) and apparent moisture sink (Q2) profiles associated with seasonal and diurnal variations of convective systems observed during the two intensive operational periods (IOPs) of the Green Ocean Amazon (GoAmazon2014/5) experiment, which was conducted near Manaus, Brazil in 2014 and 2015. The derived large-scale fields have large diurnal variations according to convective activity in the GoAmazon region and the morning profiles show distinct differences between the dry and wet seasons. In the wet season, propagating convective systems originating far from the GoAmazon region are often seen in the early morning, while in the dry season, they are rarely observed. Afternoon convective systems due to solar heating are frequently seen in both seasons. Accordingly, in the morning, there is strong upward motion and associated heating and drying throughout the entire troposphere in the wet season, which is limited to lower levels in the dry season. In the afternoon, both seasons exhibit weak heating and strong moistening in the boundary layer related to the vertical convergence of eddy fluxes. A set of case studies of three typical types of convective systems occurring in Amazonia – i.e., locally-occurring systems, coastal-occurring systems and basin-occurring systems – is also conducted to investigate the variability of the large-scale environment with different types of convective systems.


Author(s):  
B. F. Lessi ◽  
M. G. Reis ◽  
C. Z. Fieker ◽  
M. M. Dias

Abstract Birds play a key role in ecosystem dynamics, including urban and rural areas, bringing environmental quality improvements and ecological stability. Species contribute directly to natural regeneration of vegetation and succession processes, by offering ecosystem services as seed dispersal, an important role in human-modified areas. We studied the assemblages of fruit-eating birds in riparian environments of Monjolinho basin, central São Paulo state, southeastern Brazil. Birds were recorded in 41 points distributed in riparian ecosystems alongside waterbodies, in landscapes with five types of surrounding matrices: urban, periurban, farmland, and native vegetation. We described how assemblages are structured aiming to evaluate the possible influence of seasonality and landscape type. We recorded 39 bird species that can play a role as seed-dispersers, 32 in wet season and 32 in dry season. There were no significant differences in the diversity and dominance of species between seasons considering the entire area, indicating stability of basic assemblage structure. However, total number of individuals of all species recorded in different landscapes were influenced by seasonality. Also, the composition and abundance of species significantly changed between seasons, leading to a high dissimilarity with almost 50% of the species contributing with almost 90% of the observed variation. A higher taxonomic diversity and distinctness pointed to a wider array of possible seed dispersal services in natural areas, while the lowest values of indexes were found in human-modified areas. The higher number of non-related bird species during dry season contrasted with the higher number of individuals during wet season, indicating that there is more possible ecosystem services offered by frugivorous birds in driest period of the year, while in the rainy period the carrying capacity of the riparian environments was increased.


2015 ◽  
Vol 35 (6) ◽  
pp. 579-582 ◽  
Author(s):  
Hermes Ribeiro Luz ◽  
João Luiz Horacio Faccini ◽  
Hélio Ricardo da Silva

Abstract: We sampled ticks from specimens of the rococo toad Rhinella schneideriby flannel dragging on two Islands located in the São Francisco River near the Três Marias hydroelectric dam, southeastern Brazil. A total of 120 toads was examined, of which 63 (52.5%) were parasitized only by Amblyomma rotundatumtotaling 96 larvae, 163 nymphs and 134 females. The burden of parasitism ranged from one to 43 ticks, with a mean intensity of infestation of 6.2±5.5 ticks per host. The tick A. rotundatumexhibited highly aggregated distribution. Peak abundance of larvae and nymphs occurred in the dry season (May to September), whereas peak abundance of females occurred in the wet season (October to April). We collected most ticks near the head and hind limbs of R. schneideri. The finding of two engorged A. rotundatumnymphs in the same resting places of two toads and the absence of this species in the dragged areas suggest a nidicolous behavior at the studied site.


2016 ◽  
Vol 64 (1) ◽  
pp. 235 ◽  
Author(s):  
Bruce E. Young Young ◽  
James R. Zook

<p>Although the Eastern Tropical Pacific is well known for its diverse fauna, the seabirds occurring off Costa Rica’s Pacific coast have received little scientific attention. With seabirds now the fastest declining avian group, a better understanding of seabird diversity and abundance in this region is urgently needed. We report on observations of Costa Rica’s Pacific seabirds made during 19 days of observations on 11 offshore trips from 2006-2010. We provide, for the first time, spatially and seasonally explicit information on the distribution of 41 species of seabirds (nine families). Species diversity is higher during the dry-wet season (36 species) and wet-dry season transitions (36 species) than during the dry season (19 species). The fauna included three threatened species (<em>Pterodroma phaeopygia</em>, <em>Procellaria parkinsoni</em>, and <em>Puffinus creatopus</em>) and two near-threatened species (<em>Psueudobulweria rostrata</em> and <em>Thalasseus elegans</em>), highlighting the importance of Costa Rican waters for the conservation of seabirds.</p><div> </div>


1980 ◽  
Vol 23 (11) ◽  
Author(s):  
A. A. Aleem

AbstractThe distribution of marine fungi in Sierra Leone is studied in the light of hydrographic and climatic factors.Altogether 27 spp. have been identified to species level, comprising 3 Phycomycetes 14 Ascomycetes and 10 Deuteromycetes. All these spp. are considered as new records to the country and about 50 % of them are inhabitants of mangrove swamps under tidal influence.The climate of Sierra Leone is characterized by two main seasons: a wet season (May - November) and a dry season (December-April).Mangrove mycota display a seasonal periodicity, increasing in number of spp. and growth intensity in the wet . season. Degradation of wood was also active during this season, apparently more by members of Deuteromycetes such as Cirrenalia spp., Periconia prolifica and Zalerion spp. than by Ascomycetes.Sea foam was also richer in fungal ascospores (including 6 spp. of Corollospora) and conidia of Deuteromycetes in the wet than in the dry season.Estuarine foam. however. comprises several Hyphomycetes of freshwater or terrestrial origin brought in by runoff during the rainy season (e.g. Alternaria, Curvularia, Drechslera, A cro sporidium , etc.)No distinct vertical zonation was displayed by the lignicolous fungi inhabiting the mangrove.The geographical distribution of the higher marine fungi under consideration has been compared with those on the opposite side of the Atlantic as well as in the Pacific and Indian Oceans. Out of 24 spp. found in Sierra Leone, 21 spp. (88 %) occur on the opposite side of the Atlantic. while an equal number is known in the Pacific. Only 15 spp. (63 %) are recorded in the Indian Ocean. The last figure is due to our limited knowledge of Indian Ocean fungi and is expected to increase in future.The distribution of mangrove fungi encountered in Sierra Leone is considered as a "community" comprising host specific forms such as Leptosphaeria avicenniae and Cytospora rhizophorae, as well as facultative forms. Out of 14 such spp. in Sierra Leone, 13 (93 %) occur in the Western Atlantic. 12(86 %) in the Pacific and 10(72 %) in the Indian Ocean so far. The close affinities of mangrove fungi in the 3 oceans, paralleled with similar affinities of mangrove floras lend support to the theory of a common center in the West-Indo Pacific for the mangrove flora and associated mycota from which a drift took place in various directions into the 3 oceans in question. The theory was postulated by Ekman (1953) for the distribution of tropical fauna and found support by Macnae (1968) for the distribution of the mangrove flora and fauna. It also allows for an endemic element as the drift deviates from the center.The closer affinities between Eastern and Western Atlantic mycota could be explained by the current gyres to the north and south of the equator and their role in transporting mangrove seeds. wood and associated fungi between the African arid American coastlines.


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