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91.
Ana J. Abascal Sonia Castanedo Raul Medina Maria Liste 《Marine pollution bulletin》2010,60(11):2099-2110
A statistical oil spill response model is developed and validated by means of actual oil slick observations reported during the Prestige accident and trajectories of drifter buoys. The model is based on the analysis of a database of hypothetical oil spill scenarios simulated by means of a Lagrangian transport model. To carry out the simulations, a re-analysis database consisting of 44-year hindcast dataset of wind and waves and climatologic daily mean surface currents is used. The number of scenarios required to obtain statistically reliable results is investigated, finding that 200 scenarios provide an optimal balance between the accuracy of the results and the computational effort. The reliability of the model was analyzed by comparing the actual data with the numerical results. The agreement found between actual and numerical data shows that the developed statistical oil spill model is a valuable tool to support spill response planning. 相似文献
92.
Mathieu Gouhier Andrew Harris Sonia Calvari Philippe Labazuy Yannick Guéhenneux Franck Donnadieu Sébastien Valade 《Bulletin of Volcanology》2012,74(4):787-793
Etna's January 2011 eruption provided an excellent opportunity to test the ability of Meteosat Second Generation satellite's
Spinning Enhanced Visible and InfraRed Imager (SEVIRI) sensor to track a short-lived effusive event. The presence of lava
fountaining, the rapid expansion of lava flows, and the complexity of the resulting flow field make such events difficult
to track from the ground. During the Etna's January 2011 eruption, we were able to use thermal data collected by SEVIRI every
15 min to generate a time series of the syn-eruptive heat flux. Lava discharge waxed over a ~1-h period to reach a peak that
was first masked from the satellite view by a cold tephra plume and then was of sufficient intensity to saturate the 3.9-μm
channel. Both problems made it impossible to estimate time-averaged lava discharge rates using the syn-eruptive heat flux
curve. Therefore, through integration of data obtained by ground-based Doppler radar and thermal cameras, as well as ancillary
satellite data (from Moderate Resolution Imaging Spectrometer and Advanced Very High Resolution Radiometer), we developed
a method that allowed us to identify the point at which effusion stagnated, to allow definition of a lava cooling curve. This
allowed retrieval of a lava volume of ~1.2 × 106 m3, which, if emitted for 5 h, was erupted at a mean output rate of ~70 m3 s−1. The lava volume estimated using the cooling curve method is found to be similar to the values inferred from field measurements. 相似文献
93.
Marcela Z. Corazza Taufik Abr?o Fábio Grandis Lepri Sonia M. N. Gimenez Elisabeth Oliveira Maria Josefa Santos 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(8):1063-1079
Monte Carlo simulation (MCS) methodology has been applied to explain the variability of parameters for pollutant transport and fate modeling. In this study, the MCS method was used to evaluate the transport and fate of copper in the sediment of the Tibagi River sub-basin tributaries, Southern Brazil. The statistical distribution of the variables was described by a dataset obtained for copper concentration using sequential extraction, organic matter (OM) amount, and pH. The proposed stochastic spatial model for the copper transport in the river sediment was discussed and implemented by the MCS technique using the MatLab 7.3? mathematical software tool. In order to test some hypotheses, the sediment and the water column in the river ecosystem were considered as compartments. The proposed stochastic spatial model makes it possible to predict copper mobility and associated risks as a function of the organic matter input into aquatic systems. The metal mobility can increase with the OM posing a rising environmental risk. 相似文献
94.
95.
Alain Prinzhofer Jean Pierre Girard Stphane Buschaert Yvon Huiban Sonia Noirez 《Chemical Geology》2009,260(3-4):269-277
A methodology has been developed to determine chemical and carbon isotopic compositions of trace amounts of hydrocarbon gas compounds (methane, ethane, propane, iso- and normal-butane) present as dissolved compounds in the porewater of the low permeability Callovo-Oxfordian argillites in eastern Paris Basin, France. Results indicate that the studied hydrocarbons contain significant amounts of ethane, butane and propane, in addition to methane. Carbon isotopic compositions reflect primarily thermogenic origin (thermal cracking of organic matter), and lack of any significant biodegradation. Because temperature did not exceed 50 °C in the studied argillites, investigated hydrocarbons must have originated in hotter/deeper organic-bearing formations, possibly Stephanian coals. Data supports the predominance of high maturity thermogenic gas in the upper part of the Callovo-Oxfordian, and low maturity thermogenic gas mixed with minor bacterially produced methane in the lower part of the formation. A mixing between three end-member gases models quite well the data: one thermogenic gas with a low maturity (42% methane, with a δ13C of − 53‰), a gas with higher maturity (55% methane, with a δ13C of − 47‰) and a bacterial gas (99.45% methane, with a δ13C of − 80‰). This study illustrates that migration of hydrocarbon gases can take place in rocks with very low permeability and porosity, such as compacted mudrocks, given enough time. It further suggests that the studied fluid migration and transfer in aquitards would help characterization and understanding of fluid movements in sedimentary basins, as a complement to studies focused on water aquifers and hydrocarbon reservoirs. Chemical and isotopic composition of dissolved hydrocarbons in porewater can be used as natural tracers of fluid circulation in sedimentary basins, in addition to more conventional tracers. 相似文献
96.
Sonia Boehmer-Christiansen 《Marine Policy》1984,8(1):44-55
This article evaluates the effectiveness of four regional pollution agreements concluded during the 1970s: The Bonn Agreement, the Oslo Convention, the Paris Convention and the Helsinki Convention. The treaties are described and their implementation to 1980 outlined. The issue of EEC participation in environmental protection in Europe is analysed and problems of overlap with the treaties under discussion are pointed out. A major conclusion of the article is the need for more implementation research to properly assess the effectiveness of such regional agreements. 相似文献
97.
Daniele Andronico Stefano Branca Sonia Calvari Michael Burton Tommaso Caltabiano Rosa Anna Corsaro Paola Del Carlo Gaetano Garfì Luigi Lodato Lusia Miraglia Filippo Murè Marco Neri Emilio Pecora Massimo Pompilio Guiseppe Salerno Letizia Spampinato 《Bulletin of Volcanology》2005,67(4):314-330
The 2002–03 Mt Etna flank eruption began on 26 October 2002 and finished on 28 January 2003, after three months of continuous explosive activity and discontinuous lava flow output. The eruption involved the opening of eruptive fissures on the NE and S flanks of the volcano, with lava flow output and fire fountaining until 5 November. After this date, the eruption continued exclusively on the S flank, with continuous explosive activity and lava flows active between 13 November and 28 January 2003. Multi-disciplinary data collected during the eruption (petrology, analyses of ash components, gas geochemistry, field surveys, thermal mapping and structural surveys) allowed us to analyse the dynamics of the eruption. The eruption was triggered either by (i) accumulation and eventual ascent of magma from depth or (ii) depressurisation of the edifice due to spreading of the eastern flank of the volcano. The extraordinary explosivity makes the 2002–03 eruption a unique event in the last 300 years, comparable only with La Montagnola 1763 and the 2001 Lower Vents eruptions. A notable feature of the eruption was also the simultaneous effusion of lavas with different composition and emplacement features. Magma erupted from the NE fissure represented the partially degassed magma fraction normally residing within the central conduits and the shallow plumbing system. The magma that erupted from the S fissure was the relatively undegassed, volatile-rich, buoyant fraction which drained the deep feeding system, bypassing the central conduits. This is typical of most Etnean eccentric eruptions. We believe that there is a high probability that Mount Etna has entered a new eruptive phase, with magma being supplied to a deep reservoir independent from the central conduit, that could periodically produce sufficient overpressure to propagate a dyke to the surface and generate further flank eruptions.Editorial responsibility: J. Donnelly-Nolan 相似文献
98.
The Impact of Erosion on Soil Productivity—An Experimental Design Applied in São Paulo State, Brazil
Anna Tengberg Michael Stocking & Sonia Carmela Falci Dechen 《Geografiska Annaler: Series A, Physical Geography》1997,79(1-2):95-107
Soil erosion is the principal threat to agricultural sustainability, affecting both the characteristics of the in situ soil and its productive potential. However, soils vary in their resilience and there are very few empirical data upon which to appreciate the degree and type of impact on the soil caused by erosion. This paper describes an experiment designed to generate such data based on soil loss and runoff plots, and it reports on nearly nine years of experience with the design at the Instituto Agronômico, Campinas, Brazil on a Latosol (Oxisol). After seven years of erosion induced by four levels of artificial cover, the effective rainfall on the most eroded soil was 20 percent less than on the control full cover. Crop yields were also found to be significantly affected: in 1995 by nearly 700 kg/ha and in 1996 by over 1000 kg/ha—a 50% decline in yield, amounting to a loss of 4 kg/ha of maize per tonne of cumulative soil loss. Losses of nutrients (organic C, P, K, Ca and Mg) in the runoff and eroded soil were also significant with far higher levels of loss associated with the eroded sediment. Changes in the in situ soil were less clear, but a test of trends showed that the decreases in organic matter and increases in acidity could unambiguously be attributed to soil erosion. Average enrichment ratios of the eroded sediment were 1.3 for organic C, 2.6 for P, 0.7 for K, 1.3 for Ca and 1.2 for Mg. Erosion has also affected the maize quality—mainly N, Ca and B nutrient content. Through these various measures, we conclude that seven years of induced erosion has had a marked effect on soil productivity, and for the first time we are now in a position to begin calculating the financial impact of the erosion process on future yields and farmer livelihoods. 相似文献
99.
Experimental melting relationships for a mafic minette (mica-lamprophyre) from Buell Park, Arizona were determined under fO2 conditions equivalent to the ironwüstite-graphite and quartz-fayalite-magnetite buffers, at pressures of 10–20 kbar. A comparison between experimental products and phenocrysts in the most primitive minettes indicates that those lavas preserve a near-liquidus assemblage of olivine, diopside and Ti-rich phlogopite crystallized in the upper mantle under fO2QFM and in the presence of an H2O-bearing fluid phase. It is suggested that micalamprophyric (minette) magmas may originate from a metasomatized, garnet-bearing peridotitic source at deeper levels in the mantle (P20 kbar) but can also be in equilibrium with a phlogopite-bearing wehrlite (±opx) source at pressures of 17–20 kbar, under reducing or oxidizing mantle conditions. Owing to their rapid crystallization rate and high liquidus temperatures, a series of potassic daughter melts (potassic latites and felsic minettes) can be formed by segregation from mafic minette parents during their ascent through the cooler continental crust. The preservation of olivine in equilibrium with phlogopite phenocrysts in primitive minettes precludes a petrogenetic process dominated by assimilation/fractional crystallization in a shallow magma chamber and supports a model by which some lamprophyric magmas are brought to near surface conditions at temperatures in the range of 1,000–1,200° C and chilled rapidly. 相似文献
100.
Sonia Maria Barros de Oliveira Paulo Sergio Cardoso da Silva Barbara Paci Mazzilli Deborah Ines Teixeira Favaro Catia Heloisa Saueia 《Applied Geochemistry》2007
In the Cubatão region, southern Brazil, sediments are transported by several rivers from the Serra do Mar Ridge into the Santos estuary. Fertilizer plants have been operating along the margins of one of these rivers (Mogi River) producing a large volume of phosphogypsum, which is stockpiled in nearby areas. Surface sediments of the Mogi River were sampled upstream and downstream in relation to the point where the effluents of the phosphogypsum piles flow into the drainage system. In the vicinity of this point one sediment core was collected. Results show that REE, Ba, Zr and Th concentrations in the non-contaminated sediments are of the same order as those present in the upper continental crust. The contaminated samples present a composition affected by that of the phosphogypsum, marked by a higher concentration of these elements and a stronger degree of REE fractionation. These phosphogypsum characteristics are inherited from the Catalão igneous phosphate ore and were moderately modified by the industrial process of phosphoric acid production. The phosphogypsum signal decreases rapidly downstream, pointing to a limited area of influence of the stacks. The deepest sediments of the core are also free of contamination, representing a time interval prior to the deposition of phosphogypsum wastes on the banks of the estuary. 相似文献