Relating Hyperspectral Airborne Data to Ground Measurements in a Complex and Discontinuous Canopy     

Javier F. Calleja  Christine Hellmann  Gorka Mendiguren  Suvarna Punalekar  Juanjo Peón  Alasdair MacArthur  Luis Alonso 《Acta Geophysica》2015,63(6):1499-1515

The work described in this paper is aimed at validating hyperspectral airborne reflectance data collected during the Regional Experiments For Land-atmosphere EXchanges (REFLEX) campaign. Ground reflectance data measured in a vineyard were compared with airborne reflectance data. A sampling strategy and subsequent ground data processing had to be devised so as to capture a representative spectral sample of this complex crop. A linear model between airborne and ground data was tried and statistically tested. Results reveal a sound correspondence between ground and airborne reflectance data (R2 > 0.97), validating the atmospheric correction of the latter.  相似文献   

Hybrid simulation of a multi‐span RC viaduct with plain bars and sliding bearings          下载免费PDF全文

Giuseppe Abbiati  Oreste S. Bursi  Philippe Caperan  Luigi Di Sarno  Francisco Javier Molina  Fabrizio Paolacci  Pierre Pegon 《地震工程与结构动力学》2015,44(13):2221-2240

This paper deals with the seismic response assessment of an old reinforced concrete viaduct and the effectiveness of friction‐based retrofitting systems. Emphasis was laid on an old bridge, not properly designed to resist seismic action, consisting of 12 portal piers that support a 13‐span bay deck for each independent roadway. On the basis of an OpenSEES finite element frame pier model, calibrated in a previous experimental campaign with cyclic displacement on three 1:4 scale frame piers, a more complex experimental activity using hybrid simulation has been devised. The aim of the simulation was twofold: (i) to increase knowledge of non‐linear behavior of reinforced concrete frame piers with plain steel rebars and detailing dating from the late 1950s; and (ii) to study the effectiveness of sliding bearings for seismic response mitigation. Hence, to explore the performance of the as built bridge layout and also of the viaduct retrofitted with friction‐based devices, at both serviceability and ultimate limit state conditions, hybrid simulation tests were carried out. In particular, two frame piers were experimentally controlled with eight‐actuator channels in the as built case while two frame piers and eight sliding bearings were controlled with 18‐actuator channels in the isolated case. The remaining frame piers were part of numerical substructures and were updated offline to accurately track damage evolution. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

An Excel Macro to Plot the HFE‐Diagram to Identify Sea Water Intrusion Phases          下载免费PDF全文

Elena Giménez‐Forcada  F. Javier Sánchez San Román 《Ground water》2015,53(5):819-824

A hydrochemical facies evolution diagram (HFE‐D) is a multirectangular diagram, which is a useful tool in the interpretation of sea water intrusion processes. This method note describes a simple method for generating an HFE‐D plot using the spreadsheet software package, Microsoft Excel. The code was applied to groundwater from the alluvial coastal plain of Grosseto (Tuscany, Italy), which is characterized by a complex salinization process in which sea water mixes with sulfate or bicarbonate recharge water.  相似文献   

The Negative Binomial Distribution as a Renewal Model for the Recurrence of Large Earthquakes     

Alejandro Tejedor  Javier B. Gómez  Amalio F. Pacheco 《Pure and Applied Geophysics》2015,172(1):23-31

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Characterization of Cavities Using the GPR,LIDAR and GNSS Techniques     

Miguel Angel Conejo-Martín  Tomás Ramón Herrero-Tejedor  Javier Lapazaran  Enrique Perez-Martin  Jaime Otero  Juan F. Prieto  Jesús Velasco 《Pure and Applied Geophysics》2015,172(11):3123-3137

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Computer Simulation of Packing of Particles with Size Distributions Produced by Fragmentation Processes     

Miguel Angel Martín  Francisco J. Muñoz  Miguel Reyes  F. Javier Taguas 《Pure and Applied Geophysics》2015,172(1):141-148

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Microtremor Analyses at Teide Volcano (Canary Islands,Spain): Assessment of Natural Frequencies of Vibration Using Time-dependent Horizontal-to-vertical Spectral Ratios     

Javier?AlmendrosEmail author  Francisco?Luzón  Antonio?Posadas 《Pure and Applied Geophysics》2004,161(7):1579-1596

We use time-dependent horizontal-to-vertical spectral ratios (HVSR) of microtremors to determine the dominant frequencies of vibration of the geological structures beneath several recording sites in the vicinity of Teide volcano (Canary Islands, Spain). In the microtremors, the time-dependent HVSRs (ratiograms) are a useful tool to discriminate between the presence of real dominant frequencies linked to resonances of the subsurface structure and the spurious appearance of peaks due to local transients. We verified that the results are repeatable, in the sense that microtremors recorded at the same site but at different times yield a very similar HVSR function. Two types of results are found: (1) sites where there is no resonance of the propagating microtremors, and therefore no value of a dominant frequency can be assessed; and (2) sites where a stationary peak in the HVSR is found and a dominant frequency related to resonance of the shallow structure can be estimated. These resonant frequencies show substantial spatial variations even for nearby sites, which reflects the complexity of the shallow velocity structure in the Las Cañadas area. Large dominant frequencies occur near the caldera walls and also at a few locations that coincide with the intersections of the inferred rims of the three calderas forming Las Cañadas. Small dominant frequencies also occur near the caldera rim, and may be due to discontinuities in the caldera wall and/or to local velocity anomalies. Intermediate frequencies are mostly found in the eastern part of the caldera, where a tentative profile of the basement depth has been obtained. Intermediate frequencies have also been measured south of Ucanca and south of Montaña Blanca. In view of the present results, we conclude that the use of ratiograms constitutes an improvement of the HVSR method and provides an appropriate tool to investigate the shallow velocity structure of a volcanic region.  相似文献   

Barcelona's planning strategies: from 'Paris of the South' to the 'Capital of West Mediterranean'     

Francisco Javier Monclús 《GeoJournal》2000,51(1-2):57-63

Planning strategies in Barcelona are linked to its capital city aspirations. Like other European cities, capitals and non-capitals, Barcelona throughout the course of the 20th century has drawn upon a number of different planning strategies, directed towards reinforcing its prestige at both a national and international level. During this period Barcelona has sought to become Spain's second capital, the cultural capital, the industrial capital, capital of Catalonia, capital of the West Mediterranean, etc. Always in competition with Madrid, the aspirations of capital status ranking have been ambiguous. The dream of the great monumental Barcelona of the start of the century tried to emulate the European capital cities (especially Paris). By contrast more recent strategies emphasise the new role that Barcelona can play within a south-west European macro-region. The subject raised in this paper then is two-fold. On the one hand the continuity or not in the capital aspiration starting from the recuperation of Catalonia's autonomy, with its corresponding urbanistic and architectonic connotations. On the other hand the originality and analogies between strategies carried out in Barcelona, in relation to other European cities, capitals and non-capitals.  相似文献   

A revised census of European Late Cretaceous nodosaurids(Ornithischia: Ankylosauria): last occurrence and possible extinction scenarios     

Javier Pereda-Suberbiola 《地学学报》1992,4(6):641-648

Nodosaurid ankylosaurs illustrate well the differences between European and North American faunal assemblages during the Late Cretaceous. A revised checklist of the nodosaurid specimens from the Late Cretaceous (mainly Campanian and Maastrichtian) localities of Europe reveals a more important diversity than commonly envisaged, with at least two distinct species represented. Struthiosaurus nustriacus and a new nodosaurid from the Basque-Cantabric Basin were small (body length about 3 m), presumably dwarf insular forms. AIthough a detailed stratigraphic correlation is not yet availabIe, the disappearance orrelationisnotof the nodosaurids in the Western Interior of North America and in Europe may not be simultaneous but asynchronous. If so, the extinction of the Nodosauridae occurred in the latest Maastrichtian and Struthiosaurus could be the last representative of the group.  相似文献   

Accelerated recession of a desert cliff due to sewage water disposal,Sede Boqer,Israel     

Arkin  Yaacov  Karnieli  Arnon  Issar  Arie  Mtz.-Esparza  Javier Diaz 《Environmental Geology》1986,8(4):185-192

Accelerated erosion of a desert cliff due to uncontrolled sewage water disposal was investigated at the Sede Boqer Campus in the Negev, Israel An erosional cirque formed by this water was studied as a model simulating natural processes. The cliffs consist of loess and conglomerate underlain by soft marl, clay, and chalk. The rate of erosion is of the order of 5%–8% of the volume of water discharged. The rate of incision ranges from 10 2 to 13.3 m/yr and is several orders higher than that expected under normal rainfall conditions The introduction of this new hydrological factor resulted in a severe disturbance of the morphological balance in the vicinity of the cliffs, accelerated erosion, and generated circular slides  相似文献