Observational Investigation of the Statistical Properties of Surface-Layer Turbulence in a Suburban Area of São Paulo,Brazil: Objective Analysis of Scaling-Parameter Accuracy and Uncertainties     

da Silveira  Lucas Cardoso  de Oliveira  Amauri Pereira  Sánchez  Maciel Piñero  Codato  Georgia  Ferreira  Maurício Jonas  Marques Filho  Edson Pereira  Božnar  Marija Zlata  Mlakar  Primož 《Boundary-Layer Meteorology》2022,185(2):161-195

Boundary-Layer Meteorology - Statistical properties of turbulence, specifically variances of velocity components, temperature, water vapor, and carbon dioxide densities, are observationally...  相似文献   

Climatic risk zoning for potential occurrence of cacao moniliasis disease in Northeastern Brazil under the influence of ENSO phases     

Monteiro Galvão  Ícaro  Silva Pereira  Gislaine  Sentelhas  Paulo Cesar 《Theoretical and Applied Climatology》2022,149(1-2):557-567

Theoretical and Applied Climatology - Air temperature and relative humidity are the main drivers of many fungal diseases, such as moniliasis (Moniliophthora roreri), which affects cocoa production...  相似文献   

Non-destructive microtomography-based imaging and measuring laboratory-induced degradation of travertine, a random heterogeneous geomaterial used in urban heritage   总被引：1，自引：1，他引：0  

António Maurício  Carlos Figueiredo  Carlos Alves  Manuel Pereira 《Environmental Earth Sciences》2013,69(4):1471-1480

The aim of this study is to apply X-ray microfocus computed microtomography (μ-XCT), a promising non-destructive 3D microscopy imaging technique, based on measurements of X-ray linear path attenuation coefficient, in order to study a Portuguese travertine, a random heterogeneous geomaterial used in urban heritage constructions. This study evaluates the impact of soluble sulphate salt–induced decay phenomena on texture characteristics at a micrometric scale. This is done to better describing, imaging, measuring and understanding the impact of an artificially induced sulphate-decay process on petrographic/petrophysical properties. A Portuguese travertine was chosen as the object of our study. Its laboratory-induced changes were systematically monitored, using non-destructive techniques, to determine voids (pores + fractures)/matrix fractions and size spectrum evolution based on 3-D images. This investigation demonstrates that the μ-XCT potential constitutes a valid complementary tool when analysing decay processes of complex natural materials in different environmental conditions. It clearly provides suggestive and important qualitative and/or quantitative estimates, at different spatial scales, of environmentally induced stone voids/matrix network spatial structure-texture evolution correlations. Further qualitative/quantitative parameterization assessment and statistical validation will be the next step to be taken on this study.  相似文献   

The influence of geological factors on radon risk in groundwater and dwellings in the region of Amarante (Northern Portugal)     

L. M. O. Martins  M. E. P. Gomes  L. J. P. F. Neves  A. J. S. C. Pereira 《Environmental Earth Sciences》2013,68(3):733-740

The region of Amarante (Northern Portugal) is composed of Hercynian tardi-tectonics granites and Paleozoic metasediments. Petrographic observations and SEM studies show that uranium is mainly contained within the rock in heavy accessory minerals such as apatite, zircon, monazite, uraninite, thorite and thorianite. The geological, geochemical and radiological data obtained suggest that the radon concentrations in dwellings of the studied area are mainly related with the uranium content of the rocks. Indeed, the highest contents were observed in granite AT2 of Padronelo (18.2 ppm) and the granite AT1 of Telões (10.3 ppm), with metasediments showing much lower uranium contents of 1.6 ppm; radon concentrations were evaluated in dwellings, using CR-39 passive detectors, and the results obtained in winter conditions suggest that the most productive geological units are the granites AT2 and AT1, with geometric means of 430 and 220 Bq/m³, respectively, while the metasediments show the lowest value of 85 Bq/m³. Some moderate radiometric anomalies, where uranium contents can double typical background values, were found in relation with specific fault systems of the region affecting granitic rocks, thus increasing radon risk; this is an indication of uranium mobility, likely resulting from the leaching of primary mineral supports as uraninite. Groundwater radionuclide contents show a wide range of results, with the highest activities related with granitic lithologies: 2,295 Bq/l for radon, 0.83 Bq/l for gross α and 0.71 Bq/l for gross β, presenting metasediments much lower values, in good agreement with other results obtained. Absorbed dose measured with gamma spectrometers in direct contact with the rocks is directly related with the uranium contents of the rocks, and thus works as a fast proxy for radon risk. It is concluded that radon risk is moderate to high in the granitic areas of the Amarante region and low in the metasediments of the same region.  相似文献   

Stochastic Simulation Model for the Spatial Characterization of Lung Cancer Mortality Risk and Study of Environmental Factors     

Ana Rita Oliveira  Cristina Branquinho  Maria Pereira  Amílcar Soares 《Mathematical Geosciences》2013,45(4):437-452

This paper presents a study in which the lung cancer risk in males was characterized based on a simulation model of mortality rates. Block sequential simulation of mortality rates, measured in counties of different sizes, was implemented and applied to a normal grid of continental Portugal with high spatial resolution. The uncertainty in the mortality rate measurements, directly related to differences in the population size of each county, was integrated in a block direct sequential simulation through Poisson kriging of local means and variances. Three age groups were examined: 50–59, 60–69, and 70–79 years. After the continuous geographic patterns of lung cancer risk were obtained, factors potentially associated with the main areas of risk were analyzed for southern Portugal. Thus, a defined class of land use and dry weather events, related to airborne particulate matter, were found to be associated with high-risk areas, resulting in high local spatial correlation patterns in all three age groups.  相似文献   

Multi-scale approach using remote sensing images to characterize the iron deposit N1 influence areas in Carajás Mineral Province (Brazilian Amazon)     

Maria Carolina de Morais  Paulo Pereira Martins Junior  Waldir Renato Paradella 《Environmental Earth Sciences》2012,66(7):2085-2096

Mining activities cause a wide range of changes to the environment, substantially affecting both the physical and biological environmental sectors. In the Carajás Mineral Province, located in the Amazon rainforest, environmental regulations tend to be more rigorous, due to the fragility of the environment in which large iron deposits are found. The characterization of the impact of mining on environment considers: the type and extent of the impact, the physical chemistry differences and similarities of the mineral deposits, the deposit size, the adopted mining process, and the environment (both natural and economic) in which the mining process was developed. Remote sensing technology is utilized in this study, in particular, the use of ortho-aerial photograph, and optical and radar images with distinct spatial resolution. These permit the elaboration in synoptic maps, multi-scale and dynamic, of the changes wrought upon the environment: deforestation, removal of vegetation cover, topographic surface and landscape alteration, and slope instabilities among others. In this aspect, determining the extent of influence of the mining activity is directly tied to the characterization of its impact on various natural systems at the observed scale, and not by simply defining a predetermined Euclidean distance. The results showed that remote sensing technology, optical and radar images, proved to be efficient in the study of environmental information and the areas of influence on the semi-regional and local scales in the Amazon forest.  相似文献   

Monitoring of soil subsidence in urban and coastal areas due to groundwater overexploitation using GPS     

Sylvana Melo dos Santos  Jaime Joaquim da Silva Pereira Cabral  Ivaldo Dario da Silva Pontes Filho 《Natural Hazards》2012,64(1):421-439

The global positioning system (GPS) is widely used for determining the three-dimensional position of points on earth surface. In the last few years, its use has also been increasingly employed for obtaining vertical geometric coordinates, which associated with the orthometrical altitude of the point can be employed in various civil engineering applications, as has been seen in diverse localities throughout the world. The satisfactory performance of this technology for obtaining excellent precision in vertical coordinates demands some conditions, related to the satellites, such as transmission of signals and, principally, in the case of urbanized areas, the presence of obstructions in the proximity of the equipment, which interferes with the quality and quantity of the information collected. GPS is an efficient technique for the detection of small movements, including the monitoring of soil subsidence. The present article describes adequate forms of the use of GPS in such a way as to guarantee good precision of the resulting vertical coordinates, even under unfavorable situations, such as in coastal areas, where the reference networks for monitoring are implanted in only one of the sides of the point?Cobject region, which makes the situation more difficult and requires careful planning so that the use of GPS reaches the desired precision.  相似文献   

Solar-Terrestrial Signal Record in Tree Ring Width Time Series from Brazil     

Nivaor Rodolfo Rigozo  Cláudio Sergio Lisi  Mário Tomazello Filho  Alan Prestes  Daniel Jean Roger Nordemann  Mariza Pereira de Souza Echer  Ezequiel Echer  Heitor Evangelista da Silva  Valderez F. Rigozo 《Pure and Applied Geophysics》2012,169(12):2181-2191

This work investigates the behavior of the sunspot number and Southern Oscillation Index (SOI) signal recorded in the tree ring time series for three different locations in Brazil: Humaitá in Amaz?nia State, Porto Ferreira in S?o Paulo State, and Passo Fundo in Rio Grande do Sul State, using wavelet and cross-wavelet analysis techniques. The wavelet spectra of tree ring time series showed signs of 11 and 22?years, possibly related to the solar activity, and periods of 2–8?years, possibly related to El Ni?o events. The cross-wavelet spectra for all tree ring time series from Brazil present a significant response to the 11-year solar cycle in the time interval between 1921 to after 1981. These tree ring time series still have a response to the second harmonic of the solar cycle (5.5?years), but in different time intervals. The cross-wavelet maps also showed that the relationship between the SOI x tree ring time series is more intense, for oscillation in the range of 4–8?years.  相似文献   

Resolution of GPR bowtie antennas: An experimental approach     

Fernando I. Rial  Manuel Pereira  Henrique Lorenzo  Pedro Arias  Alexandre Novo 《Journal of Applied Geophysics》2009,67(4):367

Since target reflections directly depend on the emitted pulse characteristics, a key factor for carrying out a successful GPR survey is to know as much as possible about the transmission features of the antennas used. This information is very important in order to choose the right antennas and set the appropriate configuration parameters for a specific survey. With this in mind this paper deals with the development of a set of laboratory experiments on the resolution capabilities of three bowtie antennas at frequencies of 500, 800 and 1000 MHz. Results from these measurements give a first estimation of the resolution of the antennas under test, showing the advantage of performing experiments rather than relying only on theoretical assumptions. The results are also expressed in terms of the central wavelength for each antenna and compared with some theoretical estimations proposed in the specialized bibliography.  相似文献   

Artificial neural networks applied to mineral potential mapping for copper-gold mineralizations in the Carajás Mineral Province, Brazil     

Emilson Pereira Leite  Carlos Roberto de Souza Filho 《Geophysical Prospecting》2009,57(6):1049-1065

Motivated by recent successful results of artificial neural network modelling in a variety of problems related to the geosciences, we have applied a radial basis functional link net to a regional-scale mapping of the potential for Cu-Au mineralizations in the Carajás Mineral Province, northern Brazil. To derive the input feature vectors, we have used geological and both radiometric and magnetic geophysical data. A k -fold cross-validation method was employed in order to tune the parameters of the network and to select the best radial basis functional link net model amongst several others. Subsets of the available data set were used for training and validation and the estimated overall accuracy of the selected model is 91.7%. The plotting of a cumulative area versus favourability curve allowed us to define favourability zones of occurrences of Cu-Au mineralizations and to assess the efficiency and the predictive power of the model. A binary map showing high and low favourability sectors was produced for the study area as an end product that can be used to guide and support more detailed exploration efforts. Our results show that 4.18% of the study area has an extremely high potential to contain Cu-Au mineralizations, especially those of iron-oxide Cu-Au type, which are related to volcanic rocks and hydrothermal alteration.  相似文献