Teoria de carteiras e a alocação de parques eólicos offshore

The consumption of energy on the planet is currently based on fossil fuels. They are responsible for adverse effects on the environment. Renewables propose solutions for this scenario, but must face issues related to the capacity of the power supply. Wind energy offshore emerging as a promising alternative. The speed and stability are greater winds over oceans, but the variability of these may cause inconvenience to the generation of electric power fluctuations. To reduce this, a combination of wind farms geographically distributed was proposed. The greater the distance between them, the lower the correlation between the wind velocity, increasing the likelihood that together achieve more stable power system with less fluctuations in power generation. The efficient use of production capacity of the wind park however, depends on their distribution in marine environments. The objective of this research was to analyze the optimal allocation of wind farms offshore on the east coast of the U.S. by Modern Portfolio Theory. The Modern Portfolio Theory was used so that the process of building portfolios of wind energy offshore contemplate the particularity of intermittency of wind, through calculations of return and risk of the production of wind farms. The research was conducted with 25.934 observations of energy produced by wind farms 11 hypothetical offshore, from the installation of 01 simulated ocean turbine with a capacity of 5 MW. The data show hourly time resolution and covers the period between January 1, 1998 until December 31, 2002. Through the Matlab R software, six were calculated minimum variance portfolios, each for a period of time distinct. Given the inequality of the variability of wind over time, set up four strategies rebalancing to evaluate the performance of the related portfolios, which enabled us to identify the most beneficial to the stability of the wind energy production offshore. The results showed that the production of wind energy for 1998, 1999, 2000 and 2001 should be considered by the portfolio weights calculated for the same periods, respectively. Energy data for 2002 should use the weights derived from the portfolio calculated in the previous time period. Finally, the production of wind energy in the period 1998-2002 should also be weighted by 1/11. It follows therefore that the portfolios found failed to show reduced levels of variability when compared to the individual production of wind farms hypothetical offshore

Adequação bioclimática para os espaços urbanos abertos do centro de Fortaleza, CE

This research presents a study investigating the correlation between the environmental-physycal charcateristics of cities and the formation of its micro-climates. The study was conducted in the central area of Fortaleza characterized as a stable and consolidated area, where the city originated and currently faces serious problems in its urban dynamics. The points of measurements were determined by the elaboration and analysis of topography maps, height of buildings, land use, type of surface coating and vegetation, following the methodology of Katzschner (1997). A zoning map was then determined, according to common morphological characteristics of the 12 measurement points, which were based on a set of Romero s (2001) bioclimatic criteria. Air measurements, temperature, humidity, intensity and direction of winds were made in transect form in two different circuits in the study area, with six points of data collection in each area, in three different times: 6:00 am, 1:00pm and 7:00pm, during two periods of the year: August 2008 and March 2009. The results verified the influence of different environmental-physical types in the behavior of the climatic variables that were collected. A verticalização tão condenada em algumas situações se bem equilibrada e controlada pode reduzir as temperaturas do ar através do sombreamento dos espaços urbanos e possibilidade de maior permeabilidade a ventilação natural. The highest average air temperature and lower humidity were recorded at the point I at all times. This situation may have been in result of the high density, poor vegetation and extended paving of the ground. According to the results, it s clear the positive influence vegetation has on easing air temperature. Another indicator observed that areas with a greater variation in building heights tend to present decreased average air temperature. High rise structure, planned in accordance to urban air quality parameters, can reduce air temperatures by the shading of urban spaces and the possibility of greater penetration of natural ventilation

Estética do apocalipse: (re) considerações acerca da (des) arborização urbana de Natal e seu contributo à saúde pública

This study intends to establish a relation between environmental degradation, particularly the devastation of the green canopy, and public health. Utilizing a mapping of the trees included in the researched area, each individual tree was analyzed according to its age, taxonomic listing, architecture, shape and size (determined by aesthetic/convenience reasons or deformed by pruning). Initially investigated were the covert reasons lying underneath the constant aggression against trees (which many times seem to contain elements of hatred and contempt) within the urban environment. In addition to that, the aspects concerning environmental modifications and the consequent impact on public health were also assessed. Two main problems promptly emerged as a result of the removal of trees: a) without a canopy to protect the areas, they became subject to winds directly blown from SW Africa and impregnated with aerosol partic les, which are common causes for respiratory disorders and, b) direct UV solar radiation, which causes some types of skin cancers and eye disorders. To reach such results, we studied the origins and formation of UV radiation induced cancers and searched for the UV radiation spectra of action, e.g., usual intensity and quantity reaching clear and shadowed spaces in a certain area and its consequences. In a second instance, we also searched for pertinent data resources in order to confirm the increase of skin cancer cases due to exposure to UV radiation and the relation between the destruction of the green canopy and the above mentioned problems. We believe that a few significant results have been achieved by this study, namely: the relation between a culture based on medieval beliefs and its consequences on the environment; how this culture exploits and deforms nature in pursuit of financial and psychological interests to a point of transforming the landscape into a copy of something devoid of any relation to latitude and altitude; and above all, the indifference concerning the alarming results carried by these modifications

Potencialidades de cultivo de macroalgas no litoral do Rio Grande do Norte (NE, Brasil): uma perspectiva de integração de dados ambientais em sistemas de informação geográfica (SIG)

Since centuries ago, the Asians use seaweed as an important source of feeding and are their greatest world-wide consumers. The migration of these peoples for other countries, made the demand for seaweed to increase. This increasing demand prompted an industry with annual values of around US$ 6 billion. The algal biomass used for the industry is collected in natural reservoirs or cultivated. The market necessity for products of the seaweed base promotes an unsustainable exploration of the natural banks, compromising its associated biological balance. In this context, seaweed culture appears as a viable alternative to prevent the depletion of these natural supplies. Geographic Information Systems (GIS) provide space and produce information that can facilitate the evaluation of important physical and socio-economic characteristics for the planning of seaweed culture. This objective of this study is to identify potential coastal areas for seaweed culture in the state of Rio Grande do Norte, from the integration of social-environmental data in the SIG. In order to achieve this objective, a geo-referred database composed of geographical maps, nautical maps and orbital digital images was assembled; and a bank of attributes including physical and oceanographical variables (winds, chains, bathymetry, operational distance from the culture) and social and environmental factors (main income, experience with seaweed harvesting, demographic density, proximity of the sheltered coast and distance of the banks) was produced. In the modeling of the data, the integration of the space database with the bank of attributes for the attainment of the map of potentiality of seaweed culture was carried out. Of a total of 2,011 ha analyzed by the GIS for the culture of seaweed, around 34% or 682 ha were indicated as high potential, 55% or 1,101 ha as medium potential, and 11% or 228 ha as low potential. The good indices of potentiality obtained in the localities studied demonstrate that there are adequate conditions for the installation of seaweed culture in the state of Rio Grande do Norte

Caracterização batimétrica e fisicooceanográfica do canal de acesso ao porto de Cabedelo/PB: uma análise ambiental ao derrame de óleo

The State of Paraíba is one of the most dynamic states of Brazil, strategically located in the northeast, is notable for the excellent potential for integration of different transportation modes forming the states of Rio Grande do Norte, Pernambuco and Alagoas. The dynamic that occurs with port activity causes changes in the space where it is installed. And the elements of this space are always more than suffering direct or indirect influences as the flow in the port is expanded. Therefore, this region became subject to the accidental spillage of oil, because it presents a heavy traffic of ships of various sizes that can run aground or collide with oil causing accidental events. The study of geomorphological and sedimentological compositions of seafloor becomes important as more is known about the relationships between these parameters and associated fauna, and can identify their preferred habitats. The database background, acoustically collected along the proposed study area, is a wealth of information, which were duly examined, cataloged and made available. Such information can serve as an important tool, providing a geomorphological survey of the sedimentary area studied, and come to subsidize, in a flexible, future decision making. With the study area Port of Cabedelo, Paraíba - Brazil, this research aimed to evaluate the influence of the tidal surface and background in modeling the seabed, including the acquisition of information about the location of submerged rocky bodies and the depth of these bodies may turn out to be natural traps for the trapping of oil in case of leaks, and obtain the relationship between types of bed and the hydrodynamic conditions present in the region. In this context, for this study were collected bathymetric data (depth) and physical oceanographic (height of water column, water temperature, intensity and direction of currents, waves and turbidity), meteorological (rainfall, air temperature, humidity, winds and barometric pressure) of the access channel to the Port of Cabedelo / PB and its basin evolution (where the cruise ships dock), and includes tools of remote sensing (Landsat 7 ETM +, 2001), so that images and the results are integrated into Geographic Information Systems and used in the elaboration of measures aimed at environmental protection areas under the influence of this scale facilities, serving as a grant to prepare a contingency plan in case of oil spills in the region. The main findings highlight the techniques of using hydroacoustic data acquisition together bathymetric surveys of high and low frequency. From there, five were prepared in bathymetric pattern of Directorate of Hydrography and Navigation - DHN, with the depth in meters, on a scale of 1:2500 (Channel and Basin Evolution of Access to Port of Cabedelo), where there is a large extent possible beachrocks that hinder the movement of vessels in the port area, which can cause collisions, running aground and leaking oil. From the scatter diagram of the vectors of currents, it can be seen as the tidal stream and undergoes a channeling effect caused by the bidirectional effect of the tide (ebb and flood) in the basin of the Port of Cabedelo evolution in NW-direction SE and the highest speed of the currents occurs at low tide. The characterization weather for the period from 28/02 to 04/07/2010 values was within the expected average for the region of study. The multidisciplinary integration of products (digital maps and remote sensing images), proved to be efficient for the characterization of underwater geomorphological study area, reaching the aim to discriminate and enhance submerged structures, previously not visible in the images

Modelo matemático para otimização dos custos de um sistema híbrido eólico-solar : aplicação no bombeamento de petróleo

This work purposes the application of a methodology to optimize the implantation cost of an wind-solar hybrid system for oil pumping. The developed model is estimated the implantation cost of system through Multiple Linear Regression technique, on the basis of the previous knowledge of variables: necessary capacity of storage, total daily energy demand, wind power, module power and module number. These variables are gotten by means of sizing. The considered model not only can be applied to the oil pumping, but also for any other purposes of electric energy generation for conversion of solar, wind or solar-wind energy, that demand short powers. Parametric statistical T-student tests had been used to detect the significant difference in the average of total cost to being considered the diameter of the wind, F by Snedecor in the variance analysis to test if the coefficients of the considered model are significantly different of zero and test not-parametric statistical by Friedman, toverify if there is difference in the system cost, by being considered the photovoltaic module powers. In decision of hypothesis tests was considered a 5%-significant level. The configurations module powers showed significant differences in total cost of investment by considering an electrical motor of 3 HP. The configurations module powers showed significant differences in total cost of investment by considering an electrical motor of 5 HP only to wind speed of 4m/s and 6 m/s in wind of 3 m, 4m and 5 m of diameter. There was not significant difference in costs to diameters of winds of 3 m and 4m. The mathematical model and the computational program may be used to others applications which require electrical between 2.250 W and 3.750 W. A computational program was developed to assist the study of several configurations that optimizes the implantation cost of an wind-solar system through considered mathematical model

A evolução da rotação estelar na vizinhança solar

Different studies point for an rotation age link following a α tα relationship. The value of the α -parameter has a strong role on the evolutionary behaviour of rotation, because it indicates how strong is the spindown once stars evolve. The well known Skumanich s relation α t −1/2, which is consistent with simple theories of angular momentum loss from rotating stars with magnetic fields and winds, is one of the best accepted. Nevertheless, several studies show clearly that such a relation cannot hold for stars much younger or much older than the Pleiades (100 Mega years) without leading to velocities much greater or much lower than those presently observed. The present study aims at improving this picture on the basis of an enlarged analyses taking into account the role of mass and metallicity on the rotation age relation, based on an unprecedented sample of about 14 000 stars in the solar neighbourhood. From this new approach we show that the α parameter it depends strongly on the stellar age and, by consequence, on the metallicity. In addition, one observes a strong dependence of the referred parameter on the single or binary status of the stars

Assinaturas antropogênicas de elementos maiores e traços em poeira urbana na cidade do Natal-RN

Although there are many studies on urban dust contamination by heavy metals in developed countries, little attention has been paid to this type of study in developing countries, including Brazil. Therefore, a series of investigations were performed to provide signatures of heavy metals in urban dust and assess the potential sources in the city of Natal - RN-Brazil. The fraction of these sediments was studied to pass through a sieve of 63 micrometers. For the study analyzed two groups of samples, one collected in September 2009 at the end of the rainy season (9 samples) and one collected in January 2010 in the dry season (21 samples). So in all, thirty sediment samples were collected from the street. Then, in Fluorescence Spectrometry X-rays were determined major elements SiO2, Na2O, K2O, Al2O3, MgO, P2O5, Fe2O3, MnO, TiO2 and CaO, and trace Rb, Cr, Ni, Cu, Zn, Sr and Pb by an ICPOES was determined Zn, V, Na, K, Ni, Mn, Mg, P, Fe, Cr, Cu, Pb, Ba, Ca and Al from leaching HCl 0.5 mol L-1 . The results of the concentrations of elements show that the greater presence of these occurs in the dry season, except for Si which is higher in the rainy season. Analyses by geoaccumulation Index (IGEO) Enrichment Factor (EF), Contamination Factor (CF), analysis correlation and Hierarchical Cluster, confirm that Zn, Cu and Pb is anthropogenic character. Zinc may be derived from various sources related to motor vehicles or the road signs and street grids. The elements Na, K, Mg and Ca may be related to droplets suspended in air containing cations and anions present in seawater (salty), common in Christmas throughout the year, brought by winds SE-NW. The elements Na, Mg, Ca and K are the most abundant in seawater and were analyzed in this study. This indicates that the source of these additional elements detected by analyzing the contamination factor may be the very sea. Moreover, Ni, Fe, Cr and Ba can be either as a source of anthropogenic geogênica. The source of Ca is different, because it comes in lime and paint (painting guides of buildings and streets) in construction materials, but may also be present in sediments in the fragments of shells or carbonate bioclasts common in the coastal area

Morfologia e sedimentologia da plataforma continental brasileira adjacente a São Bento do Norte e Caiçara do Norte-RN/NE-Brasil

This dissertation the results of a research developed in the area of São Bento do Norte and Caiçara do Norte, northern coast of the State of Rio Grande do Norte, during the period of June of 2000 to August of 2001, in the ambit of the projects MAMBMARÉ (CNPq/CTPETRO) and PROBRAL (CAPES/DAAD). The objective principal of this research was the characterization of the sedimentary dynamics of this coast, with base in data of coastal process (winds, currents, waves and tides), with topographical risings (beach profiles and dunes), satellite images and sedimentary analyses. The more specific objectives were accomplished the coastal monitoring of this coast, to verify the maintenance of an erosive tendency or progradacional after the groynes construction for contention of the erosion in the beach of Caiçara do Norte, as well as to verify the influence of the features of bottom of the platform interns adjacent on the pole petroliferous of Guamaré. The executed monitoramento allowed to identify that the movement of the sediments, along the year, in that area, is cyclical, reaching the largest oscillations during the months of winter (deposition) and they will summer (erosion). The sedimentologic studies indicated a general tendency for sands quartzosas, with gravel presence, moderately to good selected, with asymmetry predominantly negative. In agreement with the parameter of Dean (1957), used in the identification of the state morfodinâmico of the beaches, monitored beaches, are basically reflectivas with tendency to middlemen, what frames that space of the coast norte-riograndense, as a space strongly vulnerable to erosive processes. The studies developed in the platform, it interns of this area, allowed to visualize for the first time, in large scale, the distribution of the features of the submarine bottom to the batométrico coat of 25 meters. Being pointed out the presence of a high one topographical submerged, with about 5 meters of height, 1 km of width and more than 24 meters of extension, located in the platform it interns in front of São Bento do Norte; coincident with the trend of the system of flaws of Carnaubais. This feature relay an important paper on the control of the sedimentary processes and oceanographic, as well as in the coastal evolution of this area of the RN state, and they affect the area of the pole petroliferous of Guamaré directly. These results contribute to a better knowledge of the processes in the area, and consequently as subsidies implantation of measures of coastal and environmental protection for the cities of São Bento do Norte and Caiçara do Norte, as well as to understand how the geological-sedimentary processes and oceanographic, in this area, are influencing the characteristics geoambientais of the pole petroliferous of Guamaré

Caracterização da dinâmica ambiental da região costeira do município de Galinhos, litoral setentrional do Rio Grande do Norte

This doctorate thesis concerning on the Characterization of the Environmental Dynamics of the Coastal Area of the Municipal district of Galinhos, Septentrional Coast of Rio Grande do Norte State, is located in the influence area of the Guamaré Petroliferous Pole, having as general objective the understanding of the active coastal dynamics in the region of Galinhos, whose specific objectives were: To study the variation of the coast line in the decades of 1954, 1967,1988, 1996, 2000, from remote sensing products; To elucidate the hypothesis of the region of Galinhos to have been an old system of islands barriers, using as basic tool the penetration radar in the soil - GPR; To monitor and to characterize the coastal dynamics of the study area starting from monthly data of beach profiles, sedimentological analysis, hydrodynamic data and environmental characterization data; which were used to feed the database of the N-NE network of Environmental Monitoring of Areas under Influence of the Petroliferous Industry;(REDE05/FINEP/CNPq/CTPETRO/ PETROBRAS). This research is justified, of the environmental point of view, by involving the mangrove ecosystem considered one of the most delicated environments of the State. From the viewpoint of the petroleum exploration, the systems of islands barriers are favorable for hydrocarbons reservoirs and, consequently important targets to the oil and gas industry, becoming this region attractive in comparison with similar lithified environments. With the results of the variability study in the position of the coast line in the Municipal district of Galinhos/RN from the analysis of remote sensing images, it was possible to investigate the changes in the coast line in temporal scale; the use of directional filters allowed to emphasize linings in the direction NE and to identify submerged features such as sandwaves. The use of GPR enabled the confirmation of paleochannels existence and thus confirmed the hypothesis that the Galinhos spit was formed from an old system of islands barriers. The results of the granulometric analyses indicated that in the summer period the sediments in the profiles A and B in the foreshore portion were classified with the granulometry of sand with scattered gravel and in the shoreface were constituted by sand, but in the winter period these same morphologic compartments were constituted by sand with sparse gravel and siltic sand respectively. In the profile C, in the summer and in the winter, the shoreface and foreshore compartments presented predominantly constituted by sand with sparse gravel. The hydrodynamic results showed that the largest wave heights were registered in the month of February (62 cm) and the highest period of 1,00 m/s in the month of May, the sense of the coastal currents was kept among the quadrants SW and NW, and the winds coming from NE were predominant. The analysis of the beach profiles demonstrated that in the profile A, although it had occurred erosion and deposition during the monitored months, the morphology of the referred profile was kept constant. In the profiles B and C, there were abrupt changes in the morphology, during the monitored months, having been identified a cyclic pattern in the features of the foreshore zone sometimes forming longitudinal sandy bars and in other times forming berm. These results evidenced, therefore, that studies of this nature are of fundamental importance for the coastal zoning, aiming subsidies to the organs managers in the closing of decisions as for the implantation of enterprises in the area, and for the industry of the petroleum through generation of information that subsidize the implementation and location of petroliferous structures adequate to this environment

Dinâmica Costeira dos Campos petrolíferos Macau/Serra, litoral setentrional do Estado do Rio Grande do Norte

This thesis describes the general behavior of the northern shore of the State of Rio Grande do Norte relating beach profile morphology with hydrodynamic and sedimentological parameters. The Macau and Serra Oil Field are inserted on this area and are under accelerated coastal erosion. At these oil fields are installed oil wells from PETROBRAS, nowadays located directly in the shoreline, under constant attacks of coastal processes (e.g. waves, tides and currents), which promote an intense morphodynamic variability of this sandy coast. The area was monitored for 24 months in three different stations (P01, P02 and P03). The methodology applied involved current techniques of beach profiles, hydrodynamical processes, remote sensing and geophysics. A synthesis of results obtained through the use of different time scales (monthly, lunar cycle, seasonal, annual) from a coastal dynamics study is presented. The average wind direction corresponded to 77ºAz (NE). The steepness of the berm and of the shoreface, as well as coastal current direction, do not present major changes, with an average of 36º for the steepness of the berm, 15º for the shoreface and 15º for the coastal current direction. This data set allows us to infer that the months of larger coastal erosion were November/2000 and April/2001, because of the largest wave parameter during this time. The months of worse coastal erosion in this area are related with the increasing wavy energy. This in turn, seems to be related to seasonal climatic variations, with the wave energy and tide currents speed increasing during months of minor precipitations (June to January). The months of worse coastal erosion were September and November, when the largest wave parameters and speed currents are measured in the area. Since these months are included on the period of minor precipitations, we related the coastal erosion to seasonal climatic variations. The results obtained during these 24 months of monitoring confirms a situation of accentuated erosion, mainly in Profile 03 (Barra do Corta-Cachorro), where the wave height, period, and coastal current speed are always larger than the values found in Profile 02 (Macau5). Probably these values are more expressive in Profile 03, because it does not present any natural structure of protection against the wave impacts, as the barrier island located at Ponta do Tubarão, or the sand banks in front of Macau5. The transport of the sediments occurs from East to West, and the sand accumulation is more pronounced on Profile 03 intertidal zone, where there are embrionary dunes in dryer months. The tidal currents speed, on the other hand, is more accentuated in the Macau5 area (Profile 02). At Ponta do Tubarão, the tidal currents presented a preferential direction for NE, at times of flood, currents and for NW, at times of ebb current; at Barra do Corta-Cachorro the direction of the currents were predominantly for NW, independent of the tide phase, coinciding with the preferential direction of the longshore current. This currents inversion at Ponta do Tubarão is attributed to the presence of the Ponta do Tubarão island barrier and by the communication channel of the lagoon with the sea. The tide currents are better observed in protected areas, as in the Ponta do Tubarão, when they present inversion in their direction accordingly to the flood and ebb tide. In open areas, as in Barra do Corta-Cachorro, the tide currents are overprinted by the longshore currents. Sediment analysis does not show important modifications in grain size related to seasonality (dry- and rainy seasons). On the foreshore and backshore zones, the sediments vary from fine to medium sand, while in the shoreface they very from fine to very sands. The grains are mostly spheres, varying from sub rounded to sub angled. Quartz is the main component alongside Feldspat and heavy minerals as accessory components. Biogenic content is also present and mainly represented by mollusks fragments. The calculated sediment transport show values around 100 m3/day. The morphodynamic studies indicated that this is a reflexive area from October to April, and intermediate from May to September. The Relative Tide Range-RTR for this area is 4 < RTR < 15, and so classified in the mixed wave-tide group. Having this exposed we can affirm that the more active natural factors in this area are the currents, followed by the tides and the winds. The anthropic factors are exclusively local and punctual (Macau and Serra Oil Field). Taking in account the economic importance of the area, as well as the intensity of coastal processes acting on this shore, it is important a continuity of the monthly environmental monitoring looking for variations on longer-period cycles. These data have been stored on the geo-referenced database of the projects MARPETRO and PETRORISCO (REDE 05), aiming to model the coastal and sea environment, susceptible to oil spills and their derivatives

Modelagem do clima de ondas e seus efeitos sobre as feições morfológicas costeiras no litoral setentrional do Rio Grande do Norte

This thesis presents the results of application of SWAN Simulating WAves Nearshore numerical model, OF third generation, which simulates the propagation and dissipation of energy from sea waves, on the north continental shelf at Rio Grande do Norte, to determine the wave climate, calibrate and validate the model, and assess their potential and limitations for the region of interest. After validation of the wave climate, the results were integrated with information from the submarine relief, and plant morphology of beaches and barrier islands systems. On the second phase, the objective was to analyze the evolution of the wave and its interaction with the shallow seabed, from three transverse profiles orientation from N to S, distributed according to the parallel longitudinal, X = 774000-W, 783000-W e 800000-W. Subsequently, it was were extracted the values of directional waves and winds through all the months between november 2010 to november 2012, to analyze the impact of these forces on the movement area, and then understand the behavior of the morphological variations according to temporal year variability. Based on the results of modeling and its integration with correlated data, and planimetric variations of Soledade and Minhoto beach systems and Ponta do Tubarão and Barra do Fernandes barrier islands systems, it was obtained the following conclusions: SWAN could reproduce and determine the wave climate on the north continental shelf at RN, the results show a similar trend for the measurements of temporal variations of significant height (HS, m) and the mean wave period (Tmed, s); however, the results of parametric statistics were low for the estimates of the maximum values in most of the analyzed periods compared data of PT 1 and PT 2 (measurement points), with alternation of significant wave heights, at times overrated with occasional overlap of swell episodes. By analyzing the spatial distribution of the wave climate and its interaction with the underwater compartmentalization, it was concluded that there is interaction of wave propagation with the seafloor, showing change in significant heights whenever it interacts with the seafloor features (beachrocks, symmetric and asymmetric longitudinal dunes, paleochannel, among others) in the regions of outer, middle and inner shelf. And finally, it is concluded that the study of the stability areas allows identifications of the most unstable regions, confirming that the greatest range of variation indicates greater instability and consequent sensitivity to hydrodynamic processes operating in the coastal region, with positive or negative variation, especially at Ponta do Tubarão and Barra do Fernandes barrier islands systems, where they are more susceptible to waves impacts, as evidenced in retreat of the shoreline

Estudo evolutivo das condições ambientais da região costeira do município de Guamaré - RN

The work concerns on the evolutionary study of the environmental conditions of the coastal area of Guamaré-RN, where was investigated the geo-environmental transformation occourred in this region, whose primordial purpose was to diagnose the changes verified in the temporary space of five decades (1950 to 2001). With the objective of evaluanting the action of the active coastal processes (currents, waves, tides and winds), in order to understand the generating mechanisms of the erosion/sedimentation, evidenced by constant morphologic changes. The adopted methodological procedure consisted of a succession of stages, involving bibliographical and cartographic study, aereal photographs study, digital treatment of images, field work (sample collection, beaches profiles, characterization of the beach environment and morfodynamics), mapping correction and laboratory analyses (granulometry). The evolutionary study of the morphologic features indicated significant variations in the studied period, mainly, in the dunes, sea terraces, variation of the shore line and tidal flat, evidencing the largest transformations in the temporary space between 1988 and 2001. The analyses of the beach profiles showed a sedimentation tendency in the area of the profiles P1, P2 and P3, however in the monitored pediod, it was observed in the referred profiles, erosive and depositionals intervals evidencing a need of more effective monitoring. The results of the granulometric analyses indicate a predominance of mean to coarse sand in the backshore and estirancy area, as in the shoreface, the analyses indicated medium to fine sand. The morfodynamic state, showed that beach of Minhoto is intermediate state, with alternancy to reflective. The areas of larger vulnerability and sensibility are the tidal flat, shore line, barrier island and mobile dunes, that actually is suffering great environmental impact with expansion of the carcinoculture, urban presence and natural impacts (erosion of the shoreline)

Monitoramento costeiro das praias de São Bento do Norte e Caiçara do Norte RN: implicações para o pólo petrolífero de Guamaré

This dissertation the results of a research developed in the area of São Bento do Norte and Caiçara do Norte, northern coast of the State of Rio Grande do Norte, during the period of June of 2000 to August of 2001, in the ambit of the projects MAMBMARÉ (CNPq/CTPETRO) and PROBRAL (CAPES/DAAD).The objective principal of this research was the characterization of the sedimentary dynamics of this coast, with base in data of coastal process (winds, currents, waves and tides), with topographical risings (beach profiles and dunes), satellite images and sedimentary analyses. The more specific objectives were accomplished the coastal monitoring of this coast, to verify the maintenance of an erosive tendency or progradacional after the groynes construction for contention of the erosion in the beach of Caiçara do Norte, as well as to verify the influence of the features of bottom of the platform interns adjacent on the pole petroliferous of Guamaré. The executed monitoramento allowed to identify that the movement of the sediments, along the year, in that area, is cyclical, reaching the largest oscillations during the months of winter (deposition) and they will summer (erosion). The sedimentologic studies indicated a general tendency for sands quartzosas, with gravel presence, moderately to good selected, with asymmetry predominantly negative. In agreement with the parameter of Dean (1957), used in the identification of the state morfodinâmico of the beaches, monitored beaches, are basically reflectivas with tendency to middlemen, what frames that space of the coast norteriograndense, as a space strongly vulnerable to erosive processes. The studies developed in the platform, it interns of this area, allowed to visualize for the first time, in large scale, the distribution of the features of the submarine bottom to the batométrico coat of 25 meters. Being pointed out the presence of a high one topographical submerged, with about 5 meters of height, 1 km of width and more than 24 meters of extension, located in the platform it interns in front of São Bento do Norte; coincident with the trend of the system of flaws of Carnaubais. This feature relay an important paper on the control of the sedimentary processes and oceanographic, as well as in the coastal evolution of this area of the RN state, and they affect the area of the pole petroliferous of Guamaré directly. These results contribute to a better knowledge of the processes in the area, and consequently as subsidies implantation of measures of coastal and environmental protection for the cities of São Bento do Norte and Caiçara do Norte, as well as to understand how the geological-sedimentary processes and oceanographic, in this area, are influencing the characteristics geoambientais of the pole petroliferous of Guamaré

Experimento de fluxo de sedimentos em um segmento de campo de dunas eólicas costeiras de Jenipabu - Litoral oriental do Rio Grande do Norte.

This study analyzed measurements of the aeolian transport using vertical sand traps across the field dunes of Jenipabu, in the municipality of Extremoz, Rio Grande do Norte state to the North of Natal city. These measurements were used as parameters for the sand aeolian transport in the region. Before the field trips a map of landscape units was made. Three visits to the field were done in September 2011 (field a - the 13th, field b - the 21st, field c - the 29th), period of the year with the highest wind speed, and another in December 8th, 2011 (field d ) when the wind speed starts to decrease. The sand traps used were of the type "I" with collecting opening of 25 cm from the surface level, and type "S" with collecting opening of 25 cm located 25 cm from the surface level in six collecting points in two of the visits (fields a and d ), and sand traps of the type "T" with the collecting opening of 50 cm from the surface level in the other field trips (fields "b" and "c"). A set of records was also collected by using a portable meteorological station complemented with information such as frequency and intensity of winds, precipitation and relative air humidity in the region, from the Estação Meteorológica de Natal , located 12 km from the study area. The sediments collected were treated and the data obtained permitted calculating the ratio of sediment transport. In September, the sedimentation ratio varied from 0.01 to 11.39 kg.m-1.h-1 and in December this ratio varied from 0.33 to 1.30 kg.m-1.h-1 in the type T collectors. In type I collectors they ranged from 0.01 to 11.39 kg.m-1.h-1, while the same parameters varied from 0.01 to 0.73 kg.m-1.h-1 in type S collector. Based on the statistical analysis done, we concluded that the sediment transport increased proportionally to the wind speed 25 cm from the surface. However, this is not true above 25 cm from the surface. The transport of sediments is more intense near the surface where sedimentation ratios greater than 10 kg.m-1.h-1 were found, whilst a maximum value of 3 kg.m-1.h-1 was observed 25 cm below the surface. The volume of sediments collected increases with the increasing wind speed at the surface level, whereas this relationship is opposed far away from that surface