Solar irradiance and total ozone over El Arenosillo (Spain) during the solar eclipse of 3 October 2005     

M. Antón  A. Serrano  M.L. Cancillo  J.M. Vaquero  J.M. Vilaplana 《Journal of Atmospheric and Solar》2010,72(9-10):789-793

The ground track of the annular eclipse of 3 October 2005 crossed the Iberian Peninsula. The main objective of this work was to analyze the variability of the solar irradiance and the total ozone column during the course of this event at El Arenosillo (Southwestern Spain). For achieving this goal, two Kipp & Zonen broadband radiometers (one for measuring total solar irradiance and other for measuring ultraviolet erythemal solar irradiance), one NILU-UV multi-band instrument and one Brewer spectroradiometer were used in this work. Total irradiance (310–2800 nm), and ultraviolet erythemal radiation (UVER) were recorded at a high frequency of 5 s, showing a strong reduction (higher than 80%) of the irradiance at the maximum solar obscuration which was of 79.6%. The irradiance decrease during the course of the eclipse was positively correlated with the percentage of eclipse obscuration, showing a very high agreement (R²～0.99). The irradiance recorded at selected wavelengths from the NILU-UV instrument shows a more pronounced decrease in the UV irradiance at the lower wavelengths during the solar eclipse. Finally, the evolution of the total ozone column (TOC) derived from Brewer and NILU instruments during the eclipse presented an opposite behavior: while the Brewer derived TOC values increase about 15 DU, the NILU derived TOC values decrease about 11 DU. This opposite behavior is mainly related to an artifact in the spectral irradiances recorded by the two instruments.  相似文献   

Warming,and the presence of a dominant shredder,drive variation in decomposer communities in a mountain stream     

Cátia Domingos  Verónica Ferreira  Cristina Canhoto  Christopher Swan 《Aquatic Sciences - Research Across Boundaries》2015,77(1):129-140

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Alternative theory for signal contribution sections and depth of investigation characteristics in electrical prospecting          下载免费PDF全文

Enrique Gómez‐Treviño  Carlos Flores 《Geophysical Prospecting》2015,63(3):740-749

We present an alternative to Roy's theorem for direct current regimes with the aim of validating the theoretical basis of signal contribution sections in electrical prospecting. Roy's theorem establishes that the electrical potential at a point can be expressed as an integral over all space of the electric field weighted by the gradient of inverse distance. The integrand is interpreted to represent elementary contributions to the potential that can be analyzed to compare different electrode arrays. Signal contribution sections and depth of investigation characteristics can be beautifully illustrated with important practical applications. However, the electric potential, being the solution of a boundary value problem, cannot be uniquely decomposed into elementary contributions. There is no guarantee for the integrand of a given integral to be meaningful in all situations. In the case of Roy's theorem, the concept has been severely criticized by respected scholars who challenged the scientific legitimacy of his approach. If we are going to keep the concept of elementary contributions alive, we need to go beyond Roy's theorem. In this paper, we develop an alternative theorem and show that it merges with the concept of sensitivity, which is unique and mathematically sound, and is also open to physical validation. This prevents any possible contradictions in the future and, equally important, eliminates the dichotomy between sensitivity and elementary contributions.  相似文献   

Steered migration in hard rock environments          下载免费PDF全文

Konstantin Tertyshnikov  Roman Pevzner  Andrej Bóna  Faisal Alonaizi  Boris Gurevich 《Geophysical Prospecting》2015,63(3):525-533

Hard rock seismic exploration normally has to deal with rather complex geological environments. These types of environments are usually characterized by a large number of local heterogeneity (e.g., faults, fracture zones, and steeply dipping interfaces). The seismic data from such environments often have a poor signal‐to‐noise ratio because of the complexity of hard rock geology. To be able to obtain reliable images of subsurface structures in such geological conditions, processing algorithms that are capable of handling seismic data with a low signal‐to‐noise ratio are required for a reflection seismic exploration. In this paper, we describe a modification of the 3D Kirchhoff post‐stack migration algorithm that utilizes coherency attributes obtained by the diffraction imaging algorithm in 3D to steer the main Kirchhoff summation. The application to a 3D synthetic model shows the stability of the presented steered migration to the presence of high level of the random noise. A test on the 3D seismic volume, acquired on a mine site located in Western Australia, reveals the capability of the approach to image steep and sharp objects such as fracture and fault zones and lateral heterogeneity.  相似文献   

Current Topics on Deformation Monitoring and Modelling,Geodynamics and Natural Hazards: Introduction     

Pablo J. González  Gerardo Herrera  Francisco Luzón  Pietro Tizzani 《Pure and Applied Geophysics》2015,172(11):2961-2964

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A new steel framing system for seismic protection of timber platform frame buildings. Implementation with hysteretic energy dissipators          下载免费PDF全文

Francisco López‐Almansa  Edgar Segués  Inmaculada R. Cantalapiedra 《地震工程与结构动力学》2015,44(8):1181-1202

This paper describes a new seismic protection system for timber platform frame buildings, either for new construction or retrofit. The system consists in connecting the timber frame to a steel structure that includes hysteretic energy dissipators designed to absorb most of the seismic input energy thus protecting the timber frame and the other steel members; alternatively, the system might use other types of dissipative devices. The steel structure consists of four steel stacks (located at each of the four façades) and steel collectors embracing each slab; the stacks and the collectors are connected, at each floor level, through the energy dissipators. The steel structure is self‐supporting, that is, the timber frame is not affected by horizontal actions and can be designed without accounting for any seismic provision; in turn, the steel members do not participate in the main load‐carrying system. The timber‐steel interface is designed to avoid any stress concentration in the transfer of horizontal forces and to guarantee that the yielding of the dissipators occurs prior to any timber failure. The energy dissipation capacity of the suggested system is discussed, and an application example on a six‐story timber building is presented; this case corresponds to highly demanding conditions because of the relatively large building height and weight, the high local seismicity, and the soft soil condition. This research belongs to a wider project aiming to promote the structural use of timber by improving the seismic capacity of wooden buildings; this research includes experiments and advanced numerical simulation. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Spatial prediction for infinite-dimensional compositional data     

Elías Salazar  Ramón Giraldo  Emilio Porcu 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(7):1737-1749

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Experimental characterization of the out-of-plane performance of regular stone masonry walls,including test setups and axial load influence     

Tiago Miguel Ferreira  Alexandre A. Costa  António Arêde  Ana Gomes  Aníbal Costa 《Bulletin of Earthquake Engineering》2015,13(9):2667-2692

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Source Separate Collection of Recyclables Reduces Chromium and Nickel Content in Municipal Solid Waste Compost          下载免费PDF全文

Rafael López  Pilar Burgos  Fernando Madrid  Ignacio Camuña 《洁净——土壤、空气、水》2015,43(3):427-433

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Hydrological implications of land use and land cover change: Spatial analytical approach at regional scale in the closed basin of the Cuitzeo Lake,Michoacan, Mexico     

M.E. Mendoza  G. Bocco  E. López‐Granados  M. Bravo Espinoza 《Singapore journal of tropical geography》2010,31(2):197-214

A spatially distributed water balance model was used to assess the influence of regional land use and land cover change in a poorly gauged basin for the years 1975 and 2000. To carry out this study in the Cuitzeo Lake basin in Michoacan, Mexico, remote sensing and geographic information system tools were integrated in the water balance model. In addition, a transition matrix analysis was used to determine the dynamic change of categories of related hydrologic processes. The analysis of the water balance components, based on landforms and transition matrix, indicated a tendency of improvement in the regional hydrologic conditions in the basin. As a consequence of urban land use growth, however, plains and footslopes of the basin showed an increase of runoff values. In addition, in both years, the topographic lower sections of the basin exhibited a high demand for water from the increased urban land use, along with degradation of Cuitzeo Lake, particularly by pollution and reduction of water supply. The approach used here is suitable for understanding the change in quantity and spatial distribution of water available in poorly gauged basins.  相似文献