Silvia Beatriz Alves Rolim

Metal content and distribution in surface sediments in an industrial region

The present study aimed to evaluate Cu, Cr, Ni, Zn, Pb, Mn, Al, and Fe contents, as well as their geochemical partitioning in Sinos River basin sediments in southern Brazil. This basin is a densely populated area with a substantial number of industries, especially metallurgy, electroplating works, steel mills, petrochemicals, and tanneries. The total metal concentrations were determined by X-ray fluorescence and the sediment phase concentrations were determined by applying the BCR-701 sequential extraction method proposed by the Community Bureau of Reference of the European Community, using ICP/OES. The contents extracted by a solution of 0.5 mol/L HCl were also considered. Metal contents were evaluated in the sediment fraction <63 µm. Results in the industrialized and densely populated region showed an increase in the total concentrations of Cu, Cr, Zn, and Pb, and in the potentially mobile fractions for Cu, Cr, Zn and Ni sequentially extracted. Cr stood out particularly in the Portao stream, showing 1,286 mg/kg as a result of the total concentration, considering the tannery region influence.

Analyzing the spectral variability of tropical tree species using hyperspectral feature selection and leaf optical modeling

Abstract Hyperspectral remote sensing can provide information about species richness over large areas and may be useful for species discrimination in tropical environments. Here, we analyze the main sources of variability in leaf spectral signatures of tropical trees and examine the potential of spectroscopic reflectance measurements (450 to 2450 nm) for tree species discrimination. We assess within- and among-species spectral variability and perform a feature selection procedure to identify wavebands in which the species most differ from each other. We assess the discriminative power of these wavebands by calculating a separability index and then classifying the species. Finally, leaf chemical and structural parameters of each species are retrieved by inversion of the leaf optical model PROSPECT-5. Among-species spectral variability is almost five times greater than within-species spectral variability. The feature selection procedure reveals that wavebands, where species most differ, are located at the visible, red edge, and shortwave infrared regions. Classification of the species using these wavebands reaches 96% overall accuracy. Leaf chemical and structural properties retrieve by model inversion show that differences in leaf pigment concentrations and leaf internal structure are the most important parameters controlling the spectral variability of species. These parameters also contribute to the variation in red edge position among species.

Application of visible and near infrared spectroscopy in non-destructive evaluation of cement materials

In the twenty-first century, there has been rapid urbanization in economically emerging countries. Many scientific research studies have proposed methods to monitor the quality of materials used in engineering works. Quality inspections are most often made of structure-related materials such as concrete. All the concrete used in construction work is subjected to a test that breaks the samples to evaluate its final mechanical strength. In this sense, remote sensing can contribute to mapping and monitoring construction materials, allowing investigation and identification of various properties such as mechanical strength and water content in a non-destructive manner. The materials can be inspected directly on site, in a rapid, non-invasive, and inexpensive manner; this is crucial for the ongoing process of construction. The spectral behaviour of four different mechanical strengths of two cement materials based on Portland cement, cement paste, and mortar was observed using a FieldSpec® 3 spectroradiometer. The spectral curves generated by recording the reflected and absorbed electromagnetic radiation of the samples were interpreted based on the theory of vibrational and electronic spectroscopy. The objective of this work is to show a novel technique for assisting in the analysis of solid samples using visible and near infrared spectroscopy. Through this study, a spectral contrast between different samples of the paste and mortar was found. Besides, it was possible to detect the presence and the corresponding proportion of water in the samples. Wavelet analysis enabled records of statistical evidence of spectral contrast, and showed that the depth of water absorption features is inversely proportional to compressive strength in the cement materials under study. This work is innovative, because there are no studies in the literature on the application of this technique as an aid tool for differentiating compressive strengths of Portland-cement-based materials.

Urban heat island development during the last two decades in Porto Alegre, Brazil and its monitoring

This paper describes the development of urban heat island during the last two decades in Porto Alegre, Brazil. Landsat TM images were used for this study and image processing steps were done using MATLAB and Erdas Imagine software packages for the successful monitoring of this urban phenomenon. It is found that there was a significant increase in the surface mean temperature and land use during this period. Reforested area showed significant decrease in land surface temperature.

DTM generation from a stereo pair acquired by the China-Brazilian Earth Resources Satellite (CBERS-2) and quality control of the altimetric information

The CBERS (China–Brazilian Earth Resources Satellite) program comprised a bilateral collaboration between Brazil and China for the development, construction and launch of at least two remote sensing satellites on a sun-synchronous, 778 km orbit, carrying onboard three imaging systems (High Resolution Charge Coupled Device (HR-CCD) Camera; infrared multispectral scanner IRMSS and wide field imager (WFI)). CBERS-1 and CBERS-2 were launched in October 1999 and October 2003, respectively, and acquired data using a similar technical structure, space mission and payload. The CCD camera provides images with 113 km swath, 20 m spatial resolution and has a sideways pointing capability of ±32˚, which makes possible the acquisition of stereoscopic images. This research focused on the extraction of altimetric information from a stereo pair acquired by the CBERS-2’s HR-CCD Camera, using digital photogrammetry techniques. Additionally, a quantitative precision and accuracy analysis of the altimetric information was carried out. Tests showed a root mean square error (RMSE) value of 38 m in the computed digital terrain model (DTM) against test points extracted from existing elevation data. The correction of such bias decreased the RMSE to 27 m. Considering Brazilian Cartographic Accuracy Standards (BCAS), this altimetric information can be used for Class A cartographic documents at scales up to 1:250 000.

Physical and Mechanical Characterization of Copaifera sp. Wood Specie

The aim of this work is evaluating the behaviour of the pollutant plume in the region where the INEL (USA) experiment was released. The INEL diffusion experiment consists of a test series that was accomplished in a flat and uniform terrain under stable low wind atmospheric conditions. Thusly, accounting for the current understanding of the stable planetary boundary layer (PBL) turbulence pattern and characteristics (stable eddy diffusivities), a modelling system consisting of the WRF (Weather Research and Forecasting) and LES-PALM (Large-Eddy Simulation-Parallelized) model is employed to describe the dispersive effects associated with the wind meandering movements. The potential temperature profiles and heat fluxes generated by the WRF model will be used as initial conditions to the LES-PALM model. PALM is referred as a model to Large Eddy Simulation (LES) to atmospheric and oceanic fluxes that is destined to parallel computer architectures. The horizontal wind meandering generated by LES-PALM model will be used as initial conditions to the dispersion model based in the 3D-GILTT (3D Generalized Integral Laplace Transform Technique) technique that analytically solves the advection-diffusion equation. This technique of the integral transform combines a series expansion with an integration. In the expansion a trigonometric base, determined from the Sturm-Liouville auxiliary problem, is employed. The integration is made in all range of the transformed variable, making use of the orthogonality property of the base used in the expansion. The resultant ordinary differential equations system is analytically solved using the Laplace transform and diagonalization. The simulation results, generated from this modelling system are show to agree with the observed ground-level centreline concentrations of INEL experiments and also with those of other atmospheric dispersion models. The present study shows that the horizontal wind field provided by the coupling of two meteorological models (WRF and LES-PALM) can be used in a Eulerian diffusion model to properly simulate meandering enhanced dispersion of contaminants in a low wind speed stable PBL.

An intensity recovery algorithm (IRA) for minimizing the edge effect of LIDAR data

Abstract The terrestrial laser scanner is an equipment developed for surveying applications and is also used for many other purposes due to its ability to acquire 3D data quickly. However, before intensity data can be analyzed, it must be processed in order to minimize the edge or border effect, one of the most serious problems of LIDARs intensity data. Our research has focused on characterizing the edge effect behavior as well as to develop an algorithm to minimize edge effect distortion automatically (IRA). The IRA showed to be effective recovering 35.71% of points distorted by the edge effect, providing significant improvements and promising results for the development of applications based on TLS data intensity to many studies.

SEPARAÇÃO DE TEMPERATURA E EMISSIVIDADE A PARTIR DE IMAGENS DO INFRAVERMELHO TERMAL: ANÁLISE DE SUAS APLICAÇÕES/RESTRIÇÕES

O infravermelho termal (TIR - ThermalInfraRed) e uma porcao do espectro eletromagnetico com varias aplicacoes no Sensoriamento Remoto, tais como: geologia, climatologia, analises de processos biologicos, analises geofisicos, avaliacao de desastres e deteccao de mudancas, entre outras. No TIR a emissao de radiacao dos alvos e dominante, comparado com a reflexao, e esta radiacao e uma funcao de duas variaveis, a emissividade e a temperatura do alvo. Para estudos no TIR e necessario estimar com precisao a temperatura e/ou a emissividade a partir da radiacao medida, e isto e um problema devido a relacao nao linear existente entre estas variaveis e a radiacao medida. Por isso, nos ultimos 40 anos varios pesquisadores tem desenvolvido metodos visando minimizar este problema, porem, todos estes metodos possuem restricoes em suas aplicacoes. Assim, este trabalho tem como objetivo revisar os principais metodos propostos na literaturafacilitando a sua compreensao, reproducao, alem de criar umasinteseque permitarao leitor a escolha do metodo mais adequado a determinadas situacoes.

Use of the remote sensing to obtained the dispersing of the traces pollutants concentration: Preliminary results to the city of Rio Grande, Southern Brazil

This paper aims characterized in the quantification of the air pollutants from fertilizer industry, in Rio Grande, south of Brazil. From samples collected in situ, radiometric data and hyperspectral imaging was possible quantify the regions which showed the largest precipitation of pollutants from the production of fertilizers. For soil samples, the values of sulfate, these results comprise a range 0.004-0.077 mEq. The lowest concentrations were cataloged NW of Rio Grande and in some localities the SW of the city industrial district. To the nitrate concentration, the highest percentages were cataloged in most of the urbanized area. The range of nitrate concentration was approximately 0.010-0.092 mEq. The concentrations of nitrates and sulfates, obtained by hyperion images showed maximum values of 0.092mEq and 0.338 mEq, respectively. Both samples showed a correlation of 76% with respect to pollutant concentration.

SURFACE TEMPERATURE ANALYSIS OF A COASTAL LAGOON INTEGRATED WITH ORBITAL AND MICROMETEOROLOGICAL DATA DURING THE PASSAGE OF FRONT SYSTEMS

Water bodies have a very dynamic with different characteristics that undergo changes with the passage of frontal systems. These water systems are influenced by the air temperature, wind and other meteorological quantities. This study presents a method to measure the surface temperature of a coastal lagoon located in southern Brazil using satellite images. During the winter months of 2006 (June, July and August) the surface temperature of the pond was analyzed in the occurrence of six cold frontal systems that passed in the state of Rio Grande do Sul. Surface temperature was estimated from the product MOD11-Surface Temperature and Emissivity, of the sensor Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the EOS-TERRA orbital platform. The results showed that the temperature of the pond decreases after the passage of cold fronts and can be influenced by wind and ambient temperature. The maximum temperatures recorded in the northern region of the lagoon are on average 5 ° C higher at the front entrance than at the exit of cold fronts. This increase is related to the input of nutrients coming from the marsh of Taim. This analysis shows that measures of surface temperature in ponds, obtained by the MODIS sensor, are a feasible and efficient tool to establish relations with the wind originated during the passage of frontal systems.