Advanced Tsunami Numerical Simulations and Energy Considerations by use of 3D–2D Coupled Models: The October 11, 1918, Mona Passage Tsunami     

Alberto M. López-Venegas  Juan Horrillo  Alyssa Pampell-Manis  Victor Huérfano  Aurelio Mercado 《Pure and Applied Geophysics》2015,172(6):1679-1698

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Seismic performance assessment of masonry structures with a modified “concrete” model     

Alberto Maria Avossa  Pasquale Malangone 《Bulletin of Earthquake Engineering》2015,13(9):2693-2718

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Imprint of Climate Variability on Mesozoic Fossil Tree Rings: Evidences of Solar Activity Signals on Environmental Records Around 200 Million Years Ago?     

A. Prestes  N. R. Rigozo  D. J. R. Nordemann  E. Echer  L. E. A. Vieira  M. P. Souza Echer  C. M. Wrasse  F. L. Guarnieri 《Pure and Applied Geophysics》2014,171(8):1983-1991

Evidence of the solar activity modulation of the Earth’s climate has been observed on several parameters, from decadal to millennial time scales. Several proxies have been used to reconstruct the paleoclimate as well as the solar activity. The paleoclimate reconstructions are based on direct and/or indirect effects of global and regional climate conditions. The solar activity reconstructions are based on the production of the ¹⁴C isotope due to the interaction of cosmic ray flux and the Earth’s atmosphere. Because trees respond to climate conditions and store ¹⁴C, they have been used as proxies for both for climate and solar activity reconstructions. The imprints of solar activity cycles dating back to 10,000 years ago have been observed on tree-ring samples using ¹⁴C data, and those dating back to 20 million years ago have been analyzed using fossil tree-growth rings. All this corresponds to the Cenozoic era. However, solar activity imprints on tree rings from earlier than that era have not been investigated yet. In this work, we showed that tree rings from the Mesozoic Era (of ~200 million years ago) recorded 11- and 22-year cycles, which may be related to solar activity cycles, and that were statistically significant at the 95 % confidence level. The fossil wood was collected in the southern region of Brazil. Our analysis of the fossils' tree-ring width series power spectra showed characteristics similar to the modern araucaria tree, with a noticeable decadal periodicity. Assuming that the Earth’s climate responds to solar variability and that responses did not vary significantly over the last ~200 million years, we conclude that the solar–climate connection was likely present during the Mesozoic era.  相似文献   

A kriging approach based on Aitchison geometry for the characterization of particle-size curves in heterogeneous aquifers   总被引：2，自引：0，他引：2  

Alessandra Menafoglio  Alberto Guadagnini  Piercesare Secchi 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(7):1835-1851

We consider the problem of predicting the spatial field of particle-size curves (PSCs) from a sample observed at a finite set of locations within an alluvial aquifer near the city of Tübingen, Germany. We interpret PSCs as cumulative distribution functions and their derivatives as probability density functions. We thus (a) embed the available data into an infinite-dimensional Hilbert Space of compositional functions endowed with the Aitchison geometry and (b) develop new geostatistical methods for the analysis of spatially dependent functional compositional data. This approach enables one to provide predictions at unsampled locations for these types of data, which are commonly available in hydrogeological applications, together with a quantification of the associated uncertainty. The proposed functional compositional kriging (FCK) predictor is tested on a one-dimensional application relying on a set of 60 PSCs collected along a 5-m deep borehole at the test site. The quality of FCK predictions of PSCs is evaluated through leave-one-out cross-validation on the available data, smoothed by means of Bernstein Polynomials. A comparison of estimates of hydraulic conductivity obtained via our FCK approach against those rendered by classical kriging of effective particle diameters (i.e., quantiles of the PSCs) is provided. Unlike traditional approaches, our method fully exploits the functional form of PSCs and enables one to project the complete information content embedded in the PSC to unsampled locations in the system.  相似文献   

Mapping the environmental risk of a tourist harbor in order to foster environmental security: Objective vs. subjective assessments     

Petrosillo Irene  Vassallo Paolo  Mensa Jean Alberto  Fabiano Mauro 《Marine pollution bulletin》2010,60(7):1051-1058

A new definition of environmental security gives equal importance to the objective and subjective assessments of environmental risk. In this framework, the management of tourist harbors has to take into account managers’ perceptions. The subject of the present study is a tourist harbor in southern Italy where six different managers are present. This paper aims to assess subjectively and objectively the environmental risks associated with the harbor, and to compare the results to provide estimates of environmental security. Hereby managers have been interviewed and a simple model is used for making preliminary assessment of environmental risks. The comparison of the results highlighted a common mismatch between risk perception and risk assessment. We demonstrated that the old part of the harbor is less secure than the new part. In addition, one specific manager representing a public authority showed a leading role in ensuring the environmental security of the whole harbor.  相似文献   

Nitrogen and carbon cycling in the North Sea and exchange with the North Atlantic—A model study,Part II: Carbon budget and fluxes     

Wilfried Kühn  Johannes Pätsch  Helmuth Thomas  Alberto V. Borges  Laure-Sophie Schiettecatte  Yann Bozec  A.E. Friederike Prowe 《Continental Shelf Research》2010

The 3-d coupled physical–biogeochemical model ECOHAM (version 3) was applied to the Northwest-European Shelf (47°41′–63°53′N, 15°5′W–13°55′E) for the years 1993–1996. Carbon fluxes were calculated for the years 1995 and 1996 for the inner shelf region, the North Sea (511,725 km²). This period was chosen because it corresponds to a shift from a very high winter-time North Atlantic Oscillation Index (NAOI) in 1994/1995, to an extremely low one in 1995/1996, with consequences for the North Sea physics and biogeochemistry. During the first half of 1996, the observed mean SST was about 1 °C lower than in 1995; in the southern part of the North Sea the difference was even larger (up to 3 °C). Due to a different wind regime, the normally prevailing anti-clockwise circulation, as found in winter 1995, was replaced by more complicated circulation patterns in winter 1996. Decreased precipitation over the drainage area of the continental rivers led to a reduction in the total (inorganic and organic) riverine carbon load to the North Sea from 476 Gmol C yr⁻¹ in 1995 to 340 Gmol C yr⁻¹ in 1996. In addition, the North Sea took up 503 Gmol C yr⁻¹ of CO₂ from the atmosphere. According to our calculations, the North Sea was a sink for atmospheric CO₂, at a rate of 0.98 mol C m⁻² yr⁻¹, for both years. The North Sea is divided into two sub-systems: the shallow southern North Sea (SNS; 190,765 km²) and the deeper northern North Sea (NNS; 320,960 km²). According to our findings the SNS is a net-autotrophic system (net ecosystem production NEP>0) but released CO₂ to the atmosphere: 159 Gmol C yr⁻¹ in 1995 and 59 Gmol C yr⁻¹ in 1996. There, the temperature-driven release of CO₂ outcompetes the biological CO₂ drawdown. In the NNS, where respiratory processes prevail (NEP<0), 662 and 562 Gmol C yr⁻¹ were taken up from the atmosphere in 1995 and 1996, respectively. Stratification separates the productive, upper layer from the deeper layers of the water column where respiration/remineralization takes place. Duration and stability of the stratification are determined by the meteorological conditions, in relation to the NAO. Our results suggest that this mechanism controlling the nutrient supply to the upper layer in the northern and central North Sea has a larger impact on the carbon fluxes than changes in lateral transport due to NAOI variations. The North Sea as a whole imports organic carbon and exports inorganic carbon across the outer boundaries, and was found to be net-heterotrophic, more markedly in 1996 than in 1995.  相似文献   

Well-balanced high-order centered schemes on unstructured meshes for shallow water equations with fixed and mobile bed     

Alberto Canestrelli  Michael Dumbser  Annunziato Siviglia  Eleuterio F. Toro 《Advances in water resources》2010

In this paper, we study the numerical approximation of the two-dimensional morphodynamic model governed by the shallow water equations and bed-load transport following a coupled solution strategy. The resulting system of governing equations contains non-conservative products and it is solved simultaneously within each time step. The numerical solution is obtained using a new high-order accurate centered scheme of the finite volume type on unstructured meshes, which is an extension of the one-dimensional PRICE-C scheme recently proposed in Canestrelli et al. (2009) [5]. The resulting first-order accurate centered method is then extended to high order of accuracy in space via a high order WENO reconstruction technique and in time via a local continuous space–time Galerkin predictor method. The scheme is applied to the shallow water equations and the well-balanced properties of the method are investigated. Finally, we apply the new scheme to different test cases with both fixed and movable bed. An attractive future of the proposed method is that it is particularly suitable for engineering applications since it allows practitioners to adopt the most suitable sediment transport formula which better fits the field data.  相似文献   

PGA and structural dynamics input motion at a given site   总被引：1，自引：1，他引：0  

Fabio?CasciatiEmail author  Sara?Casciati  Alberto?Marcellini 《地震工程与工程振动(英文版)》2003,2(1):25-33

The computation of the representative ground motions, to be used as input for the dynamic analyses of a structure at a particular site, can be approached by several methods. The choice of the approach depends on two factors : the data available and the type of problem to be solved. This paper reports the experience of the authors in approaching a specific case study: the Southern Memnon Colossus, located in Luxor, Egypt. The results are of interest when the hazard analysis estimation in developing countries and the safeguard of cultural heritage are concerned. Monuments have to be treated as important structures, due to their historical and economical value. Hence, standard procedures of probabilistic seismic hazard analysis for the seismic classification of common buildings have to be disregarded. On the other hand, the consequences of the collapse of a monument are not comparable to those related to structures such as nuclear power plants and large dams, for which the deterministic seismic hazard analysis provides a straightforward framework for evaluation of the worst case ground motions. An “intermediate” approach, which requires a lower amount of input data with respect to the deterministic one, is adopted. Its stochastic component can capture significant characteristics of earthquakes, primarily the frequency contents which depend on the magnitude (often referred to as the earthquake scaling law). Supported by: European Union-ICA3-1999-00006  相似文献   

Scale radii and aggregation histories of dark haloes     

Eduard Salvador-Solé  Alberto Manrique  José María Solanes 《Monthly notices of the Royal Astronomical Society》2005,358(3):901-912

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Imaging polarimetry of comet Hale-Bopp (C/1995 O1) around perihelion     

Paolo Tanga  Alberto Cellino  Mario Di Martino 《Earth, Moon, and Planets》1997,78(1-3):359-364

The polarization distribution of the inner coma of comet Hale-Bopp was measured by CCD imaging around perihelion. The dust shell positions correlate well with relative maxima of polarization. The images taken in the I-band identify different shell systems, each showing individual polarization properties. This could be related to differences in the dust properties of the associated jets. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献