Impacts of land-use and climate changes on surface runoff in a tropical forest watershed (Brazil)     

Manuel Esteban Lucas-Borja  Bruno Gianmarco Carrà  João Pedro Nunes  Léonard Bernard-Jannin  Santo Marcello Zimbone 《水文科学杂志》2020,65(11):1956-1973

ABSTRACT

Surface runoff generation capacity can be modified by land-use and climate changes. Annual runoff volumes have been evaluated in a small watershed of tropical forest (Brazil), using the Soil and Water Assessment Tool (SWAT) model. Firstly, the accuracy of SWAT in runoff predictions has been assessed by default input parameters and improved by automatic calibration, using 20-year observations. Then, the hydrological response under land uses (cropland, pasture and deforested soil) alternative to tropical forest and climate change scenarios has been simulated. SWAT application has showed that, if forest was replaced by crops or pasture, the watershed’s hydrological response would not significantly be affected. Conversely, a complete deforestation would slightly increase its runoff generation capacity. Under forecasted climate scenarios, the runoff generation capacity of the watershed will tend to decrease and will not be noticeably different among the representative concentration pathways. Pasture and bare soil will give the lowest and highest runoff coefficients, respectively.  相似文献   

Il disastro di Quassolo (Borgofranco d'Ivrea) considerazioni sulle «mure»     

Prof. Dr. Alfredo Boni 《Pure and Applied Geophysics》1942,4(1):139-151

Riassunto Vengono analizzate le condizioni topografiche, idrografiche, geologiche e le circostanze meteorologiche concorrenti nella determinazione del fenomeno verificatosi a Quassolo (Borgofranco d'Ivrea) il 12 giugno 1942; tale fenomeno viene definito come formazione di una «mure»; su queste ultime vien fatta qualche osservazione; sono considerati da ultimo i precedenti di tali fenomeni nella regione ed i provvedimenti necessari per impedire il loro ripetersi.

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Zusammenfassung Der Verf. untersucht die begünstigenden topographischen, hydrographischen, geologischen Bedingungen und die gelegentlich bestimmenden meteorologischen Umständen der plötzlichen Denudationserscheinung vom 12 ten Juni 1942 in Quassolo (Borgofranco d'Ivrea: Aosta-Provinz) und kommt zu dem Ergebnis, dass es sich um eine Murbildung handelt. Nach einigen Betrachtungen über die Murenn werden die um das Wiederaufleben des Murbaches zu hindern nötigen Werken angegeben.

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Datos petrológicos sobre las erupciones basálticas del Bajo Ebro (España)     

San Miguel Arribas  Alfredo 《Bulletin of Volcanology》1952,12(1):183-201

Bulletin of Volcanology -  相似文献   

Mercury levels in the dissolved and particulate fractions of the Tyrrhenian sea     

Romano Ferrara  Alfredo Seritti  Corrado Barghigiani  Antonio Petrosino 《Marine Chemistry》1986,18(2-4)

Determination of the actual mercury concentration in Mediterranean basin seawater was achieved by means of an instrument based on fluorescence spectrometry developed for this purpose, during a field study aboard the oceanographic ship “L.F. Marsili”, between August 1980 and May 1982.Dissolved ·total’ and ·reactive’ mercury and mercury associated with particulate matter were determined on surface and subsurface waters in the Tyrrhenian Sea from La Spezia to Sicily.Concentrations in the range 1.4–19.7 ng l⁻¹ for ·total dissolved mercury’, 0.5–5.9 ng l⁻¹ for ·reactive dissolved mercury’ and 0.3–8.0 ng l⁻¹ for mercury associated with the particulate matter, were measured on surface and subsurface waters in the Tyrrhenian Sea from La Spezia to Sicily.Even if the mean value of the total mercury concentration (dissolved + particulate) was found to be about twice as high as those observed for the oceans, the difference does not seem to be as high as predicted by the model proposed by Buffoni and co-workers to explain the large difference of mercury levels between tunas caught, respectively, in the Mediterranean and in the Oceans.  相似文献   

A comparison of the Iberian and Ebro Basins during the Permian and Triassic, eastern Spain: A quantitative subsidence modelling approach   总被引：2，自引：0，他引：2  

Henar Vargas  Jorge M. Gaspar-Escribano  Jos Lpez-Gmez  Jan-Diederik Van Wees  Sierd Cloetingh  Raúl de La Horra  Alfredo Arche 《Tectonophysics》2009,474(1-2):160

The Permian–Triassic sediments of the Iberian Plate are a well studied case of classical Buntsandstein–Muschelkalk–Keuper facies, with good sedimentological interpretations and precise datings based on pollen and spore assemblages, ammonoids and foraminifera. Synrift–postrift cycles are recorded in these facies, but there are only a few studies of quantitative subsidence analysis (backstripping method) and only a previous one using forward modelling for the quantification of synrift–postrift phases of this period.Here we present the results obtained by the quantitative analysis of fourteen field sections and oil-well electric log records in the Iberian and Ebro Basins, Spain. Backstripping analysis showed five synrift phases of 1 to 3 million years duration followed by postrift periods for the Permian–Triassic interval. The duration, however, shows lateral variations and some of them are absent in the Ebro Basin. The forward modelling analysis, assuming local isostatic compensation, has been applied to each observation point using one-layer and two-layer lithospheric configurations. The second one shows a better fit between observation and model prediction in a systematic way, so a two layer configuration is assumed for the sedimentary basin filling analysis. Lithospheric stretching factors β and δ obtained in the forward modelling analysis are never higher than 1.2, but sometimes β < 1 and simultaneously δ > 1 in the same section. If surficial extension is compensated by deep compression either at the roots of the rift basins or in far-away zones is not yet clear, but this anomaly can be explained using a simple shear extensional model for the Iberian and Ebro basins.  相似文献   

Magnetic Basement Depth Inversion in the Space Domain     

Tiago Mane Nunes  Valéria Cristina F. Barbosa  João Batista C. Silva 《Pure and Applied Geophysics》2008,165(9-10):1891-1911

We present a total-field anomaly inversion method to determine both the basement relief and the magnetization direction (inclination and declination) of a 2D sedimentary basin presuming negligible sediment magnetization. Our method assumes that the magnetic intensity contrast is constant and known. We use a nonspectral approach based on approximating the vertical cross section of the sedimentary basin by a polygon, whose uppermost vertices are forced to coincide with the basin outcrop, which are presumably known. For fixed values of the x coordinates our method estimates the z coordinates of the unknown polygon vertices. To obtain the magnetization direction we assume that besides the total-field anomaly, information about the basement’s outcrops at the basin borders and the basement depths at a few points is available. To obtain stable depth-to-basement estimates we impose overall smoothness and positivity constraints on the parameter estimates. Tests on synthetic data showed that the simultaneous estimation of the irregular basement relief and the magnetization direction yields good estimates for the relief despite the mild instability in the magnetization direction. The inversion of aeromagnetic data from the onshore Almada Basin, Brazil, revealed a shallow, eastward-dipping basement basin.  相似文献   

Quantitative reconstruction of Late Cenozoic landscapes: a case study in the Sierra de Atapuerca (Burgos,Spain)     

Alfonso Benito‐Calvo  Alfredo Pérez‐González  Josep María Parés 《地球表面变化过程与地形》2008,33(2):196-208

We have developed a method to reconstruct palaeorelief by means of detailed geomorphological and geological studies, geostatistical tools, GIS and a DEM. This method has been applied to the Sierra de Atapuerca (NE Duero Basin, Burgos, Spain), allowing us to model a three‐dimensional reconstruction of the relief evolution from the Middle Miocene to the present. The modelling procedure is based on geostatistical recovery of the palaeosurfaces characteristic of each geomorphological evolution stage, using polynomial regressions, trend surfaces and kriging. The modelling of morphology trends has been useful in establishing new geological and geomorphological relationships in the geodynamic evolution of this basin, such as uplift quantification, correlation of erosion surfaces and sedimentary units, and the evolution of fluvial base levels. The palaeosurface reconstruction together with an analysis of the slope retreat have allowed us to reconstruct the palaeoreliefs that define the Late Cenozoic landscape evolution of this area, where the Lower and Middle Pleistocene archaeopalaeontological sites of the Sierra de Atapuerca are located. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Appraisal problem in the 3D least squares Fourier seismic data reconstruction          下载免费PDF全文

Fabio Ciabarri  Alfredo Mazzotti  Eusebio Stucchi  Nicola Bienati 《Geophysical Prospecting》2015,63(2):296-314

Least squares Fourier reconstruction is basically a solution to a discrete linear inverse problem that attempts to recover the Fourier spectrum of the seismic wavefield from irregularly sampled data along the spatial coordinates. The estimated Fourier coefficients are then used to reconstruct the data in a regular grid via a standard inverse Fourier transform (inverse discrete Fourier transform or inverse fast Fourier transform). Unfortunately, this kind of inverse problem is usually under‐determined and ill‐conditioned. For this reason, the least squares Fourier reconstruction with minimum norm adopts a damped least squares inversion to retrieve a unique and stable solution. In this work, we show how the damping can introduce artefacts on the reconstructed 3D data. To quantitatively describe this issue, we introduce the concept of “extended” model resolution matrix, and we formulate the reconstruction problem as an appraisal problem. Through the simultaneous analysis of the extended model resolution matrix and of the noise term, we discuss the limits of the Fourier reconstruction with minimum norm reconstruction and assess the validity of the reconstructed data and the possible bias introduced by the inversion process. Also, we can guide the parameterization of the forward problem to minimize the occurrence of unwanted artefacts. A simple synthetic example and real data from a 3D marine common shot gather are used to discuss our approach and to show the results of Fourier reconstruction with minimum norm reconstruction.  相似文献   

Ductility reduction factors for steel buildings considering different structural representations     

Alfredo Reyes-Salazar  Edén Bojórquez  Juan I. Velazquez-Dimas  Arturo López-Barraza  J. Luz Rivera-Salas 《Bulletin of Earthquake Engineering》2015,13(6):1749-1771

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Shaking table testing of an existing masonry building: assessment and improvement of the seismic performance          下载免费PDF全文

Nuno Mendes  Paulo B. Lourenço  Alfredo Campos‐Costa 《地震工程与结构动力学》2014,43(2):247-266

This paper aims to assess and improve the seismic performance of an existing masonry building with flexible floors, representative of a Portuguese building typology—‘gaioleiro’ buildings. The study involved seismic tests and dynamic identification tests of two models (nonstrengthened and strengthened) in the shaking table. Each model was subjected to several seismic tests with increasing amplitude. Before the first test and after each seismic test, the dynamic identification of the model was carried out, aiming at obtaining their seismic vulnerability curves based on a damage indicator obtained from the decrease of the frequencies of the modes. In the strengthened model, steel elements were used to improve the connection between walls and floors, together with ties in the upper stories. The results show that adopted strengthening technique is effective for reducing the seismic vulnerability of ‘gaioleiro’ buildings, namely for improving the out‐of‐plane behavior of the facades. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献