Synthetic scenario generation of monthly streamflows conditioned to the El Niño–Southern Oscillation: application to operation planning of hydrothermal systems

Stochastic Environmental Research and Risk Assessment - The Brazilian Interconnected Power System is hydro dominated and characterized by large reservoirs presenting multi-year regulation...     

The Potential Use of Bali Wastewater for Crop Production Based on Moscow Region Experience

The article offers a new approach to the selection of a treatment plant, based on the optimization of biogeochemical matter flows. The existing treatment facilities of Bali are analyzed. The authors propose several process schemes for domestic wastewater treatment, depending on the technology of utilization of biogenic elements from the wastewater for agricultural production. These are based on water treatment technologies that have been in use in Moscow for more than 100 years.     

Sensitivity analysis of a morphodynamic modelling system applied to a coastal lagoon inlet

This work investigates the recent morphological changes at the inlet of a complex coastal system (Ria de Aveiro lagoon, Portugal). This study was carried out using bathymetric data analysis and numerical simulations obtained with the 2DH morphodynamic modelling system MORSYS2D. The present simulations considered only tidal forcing, and a sensitivity analysis was performed by tuning the formula used to compute the sediment transports. A non-uniform sediment grain size distribution for the Ria de Aveiro inlet is considered in the numerical simulations, based on surveys performed in this area. The model results are analysed to assess if they resemble the observed trends of erosion and deposition, as calculated from bathymetric data. A quantitative analysis of the differences between the bathymetric changes obtained through surveys and the numerical results over a period of 3 years considering different sediment transport formulations shows that the formulations of Ackers and White (1973) and Engelund and Hansen (1967) are the ones that best describe the morphodynamic changes driven by tides in the Ria de Aveiro inlet.     

Determination of O3-, CO- and PM10-transport in the metropolitan area of São Paulo, Brazil through synoptic-scale analysis of back trajectories

Summary This study is aimed to qualitatively analyze the impact of remote sources on air pollution in the Metropolitan Area of S?o Paulo (MASP). Air-mass back trajectories from June to August of 1999 were calculated using a three-dimensional kinematic trajectory model and grouped into trajectory clusters. Correlations of individual trajectory clusters with O₃, CO and PM₁₀ concentrations were determined. In this model, trajectories were obtained using the means of the three wind velocity components (U, V and W). The three-dimensional wind field was derived from the Regional Atmospheric Modeling System, and downscaling was employed. Coarse and fine nested grids (64-km and 16-km horizontal resolution, respectively) were used. Every 12 h (at 00 and 12 UTC), a back-trajectory ensemble, using the 64-km grid, was calculated for five defined endpoints at intervals of 0.5° N, S, E and W of the MASP (λ = 23° 33′S, ϕ = 46° 45′W), that last endpoint being centered in the MASP. To analyze cluster trajectories, the five trajectory ensembles from each day were allocated into one of four clusters (northeast, southeast, southwest or northwest quadrant) based on the origin of the trajectory over 4 days. Days on which all five trajectories originated from the same quadrant were classified as “core” days. Core day concentrations of CO, O₃ and PM₁₀ during the study period were evaluated. The results show that, during the study period, air-mass back trajectories in the MASP originated from all four quadrants: northeast (32%), southeast (12%), southwest (19%) and northwest (37%). Our analysis of back-trajectory clusters in the MASP suggests a transport to ambient air of O₃ precursors and O₃ from the northeast region, which is associated with agricultural activities involving biomass burning.     

River breeze circulation in eastern Amazonia: observations and modelling results

Summary The CIRSAN/LBA field campaign was conducted close to two major rivers of the Amazon Basin, the Tapajós and the Amazon. The observations indicate that during weak trade wind episodes the Tapajós River breeze actually induces a westerly flow at the eastern margin with an associated line of shallow cumulus. The atmospheric circulation induced by the river has been interpreted with the help of a high resolution numerical simulation. A single cell forms during late morning over the Tapajós River and evolves into the afternoon with ascending motion in the eastern margin and a descending branch in the western margin suppressing cloud formation. During the night, convergence is seen along the centre of the River Tapajós. The implications of the particular geometry of the river with respect to the trade winds for the generalization of the surface measurements of turbulent fluxes of heat, moisture and CO₂ in the Tapajós eastern margin of the Amazon Basin as a whole are discussed.     

Holocene small mammals hunted by owls and humans in southern Brazil: taphonomic evidence and biological significance

Understanding resource utilization and economic diversification amongst Holocene hunter‐gatherers in southern Brazil requires in‐depth taphonomic analysis of faunal assemblages. Three Early to Late Holocene archaeological sites (Garivaldino, Pilger and Sangão) in Rio Grande do Sul State, southern Brazil, revealed large assemblages of small mammal (?1 kg) remains, composed mainly of rodents. To appreciate depositional processes of fauna in relation to human consumption, taphonomic attributes and processes were evaluated. The results indicated that the remains accumulated through different antemortem taphonomic pathways, apparently linked to the size and natural history of the species represented. The small‐ and medium‐sized (<150 g) cricetid rodents (e.g. Pseudoryzomys simplex and Sooretamys angouya) were represented by a low proportion of teeth with lightly digestive corrosion suggesting that they were derived from the predatory activity of owls, possibly Tyto alba. In contrast, large‐sized cricetids (>150 g; Kunsia tomentosus, Gyldenstolpia sp. and Holochilus sp.), and several caviomorph rodents with aggregated spatial distributions (Echimyidae (?Dicolpomys fossor, Phyllomys sp., ?Clyomys riograndensis and ?Euryzygomatomys mordax), Caviidae (Cavia sp.) and Ctenomyidae (Ctenomys sp.)) showed evidence of thermoalteration patterns and cut marks on bones, suggesting human exploitation. A postmortem depositional environment was deduced from dendritic and branched patterns of rootlet etching, apparent mostly at Garivaldino and Pilger. Polished areas and holes on bone surfaces, and impregnation of manganese showed moderate (Sangão) or low (Garivaldino and Pilger) incidence, pointing to water transport under moderate (Pilger) and low (Garivaldino and Sangão) energy over short distances. The results obtained here provide the first clear evidence of early human exploitation of small mammals in southern Brazil, suggesting a diversification of economies. In addition, as several of the recorded rodents are today regionally or biologically extinct, a preliminary discussion about the potential impact of humans on this process is provided.     

Three-dimensional numerical simulation for mechanized tunnelling in soft ground: the influence of the joint pattern

The main purpose of this study was to provide a three-dimensional numerical model, which would allow the tunnel lining behaviour and the displacement field surrounding the tunnel to be evaluated. Most of the processes that occur during mechanized excavation have been simulated in this model. The influence of the lining joint pattern, including segmental lining joints and their connections, has in particular been taken into consideration. The impact of the processes during mechanized excavation, such as the grouting pressure and the jacking forces in the structural forces induced in the tunnel lining, has been presented. These values depend on the tunnel advancement. However, a negligible influence of the joint pattern on the ground displacement field surrounding the tunnel has been observed. Generally, a variation in the structural forces in successive rings along the tunnel axis has been found in a staggered segmental lining, indicating the necessity of simulating the joints in the tunnel lining and using a full three-dimensional numerical model to obtain an accurate estimation. In addition, the considerable influence of the coupling effect between successive rings on the lining behaviour has been highlighted.     

Radiation-induced defects in euclase: formation of O<Superscript>−</Superscript> hole and Ti<Superscript>3+</Superscript> electron centers

Irradiation techniques are often applied to gem minerals for color enhancement purposes. Natural green, blue and colorless specimens of rare gemological quality euclase, BeAlSiO₄(OH), from Brazil were irradiated with gamma rays in the dose range from 10 to 500 kGy. Although the colors of the different specimens were not strongly influenced, two different irradiation-induced paramagnetic defect centers were found by electron paramagnetic resonance (EPR). The first one is an O⁻ hole center interacting with one Al neighbor and the second is a Ti³⁺ electron center. The EPR angular rotation patterns of both irradiation-induced defects were measured and analyzed. The results suggest that O⁻ hole centers are formed by dissociation of the hydroxyl ions, similar as in topaz crystals. In euclase the OH⁻ ions interconnect distorted Al octahedra and Be tetrahedra in O₅ positions. During irradiation, the electrons are captured by titanium ions (Ti⁴⁺ + e⁻), leading to the formation of paramagnetic Ti³⁺ ions. From the EPR rotation patterns it is clear that these ions substitute for Al ions. The spin Hamiltonian parameters of the irradiation-induced defects are analyzed and compared to similar defect centers in other mineral specimens. Thermal annealing experiments show that the O⁻ hole centers and Ti³⁺ electron centers are directly connected through the radiation process.     

Input of geophysics to understand hydrogeology towards the assessment of geoenvironmental conditions in Beira city,Mozambique

As the fourth largest city in Mozambique, and located right beside the Indian Ocean, Beira faces sanitary and environmental problems that are a strong concern to the local and national authorities. One of the major problems that Beira city has to deal with is the existence of undrinkable groundwater in many dug-wells that supply a large amount of the city population. The cooperation project among Direcção Nacional de Geologia of Mozambique, the Laboratório Nacional de Energia e Geologia of Portugal and the Instituto de Apoio ao Desenvolvimento Português that took place from 2007 to 2011 has as one of its main goals the production of the Geological and Geoenvironmental Maps of Beira at scale 1:50,000, intending to create a tool to support the implementation of governmental policies regarding sustainable groundwater and natural resources exploitations, land management and environmental protection. These goals were achieved through the identification, characterization and mapping of the different geological units and the evaluation of the city environmental problems regarding water and soil contamination in urban areas, involving the use of several methodologies that were subsequently integrated and jointly interpreted. These comprised remote sensing techniques, hydrogeology analysis and evaluation and the use of geochemistry and electrical geophysical methods. This work emphasizes the input of geophysical and hydrogeological methods to assess the geoenvironmental conditions of Beira, namely those related with the prediction of occurrence of saline and brackish water in the shallow dug-wells that supply a large amount of Beira populations, especially in the crowded suburbs. Several geophysical surveys using electrical and electromagnetic methods were conducted and interpreted regarding the evaluation of the several hypotheses that were stood for this feature. Results are related with hydrogeological conditions and organic and inorganic hydrochemical analysis. Considering these facts, this study was an important input for mapping areas with saline and brackish water imprisoned in the subsurface geological formations, using a wider set of methodologies that were integrated in these results.