Variogram-Based Descriptors for Comparison and Classification of Rock Texture Images     

Díaz  Gonzalo F.  Ortiz  Julián M.  Silva  Jorge F.  Lobos  Rodrigo A.  Egaña  Álvaro F. 《Mathematical Geosciences》2020,52(4):451-476

Mathematical Geosciences - Rock characterization is typically performed by geologists in mining companies and involves the analysis of several meters of drill-hole samples to describe distinctive...  相似文献   

Stock Evaluation of Three Littoral Echinoid Species on the Catalan Coast North-Western Mediterranean   总被引：2，自引：0，他引：2  

Cruz  Palacín  Xavier  Turon  Manuel  Ballesteros  Gonzalo  Giribet Salvador  López 《Marine Ecology》1998,19(3):163-177

Abstract. We estimated the abundances of the three common littoral echinoid species Paracentrotus lividus, Arbacia lixula and Sphaerechinus granularis in a littoral zone between 0 and 10m depth on the Catalan shores NE Spain. Densities of each species were estimated from a total number of 11 571× 1 m² sampling units deployed at 152 sites along the 13 zones into which the coast was divided. The surface area available in each of these zones was estimated at the scale of the sampling unit 1 m² taking into account the fractal dimension of the shore. The stocks individuals > 2cm test diameter of these species for the whole Catalan shore ≅ 300 km, straight-line distance were estimated to be about 279.1 × 10⁶ individuals for P. lividus , 28.9 × 10⁶ individuals for A. lixula and 10.9 × 10⁶ individuals for S. granularis. These sea-urchins are key species in the regulation of algal communities and some of them P. lividus. S. granularis are of commercial interest. This information will provide a tool for the future monitoring and management of this resource, which now faces diverse pressures of human origin.  相似文献   

Contrasting beach-ridge systems in different types of coastal settings     

Manuel F. Isla  Damián Moyano-Paz  Duncan M. FitzGerald  Lautaro Simontacchi  Gonzalo D. Veiga 《地球表面变化过程与地形》2023,48(1):47-71

Beach-ridge systems are geomorphological features common in every type of coast and have been widely interpreted as geo-archives of past sea-level, climatic, or tectonic changes. These relict morphological elements are well-known by their facies, architecture, stratigraphy, and evolution. However, the coastal context where beach ridges are formed has never been evaluated. Coastal beach-ridge systems were classified into four main types corresponding to deltaic strandplains, non-deltaic strandplains, spits, and barrier islands. Our study consisted of three scales of analysis: (1) the entire beach-ridge system; (2) beach-ridge sets; and (3) individual beach ridges. Several beach-ridge systems having formed in different types of coastal settings are compared by their present characteristics. Geomorphic data generated from processing and interpreting satellite images combined with previous studies are used to quantify multi-scale attributes of beach-ridge systems. These attributes include the area, length, width, number of sets, number of ridges per set, set rotation, ridge spacing, and ridge elevation. Our findings demonstrate that significant differences define beach-ridge systems including deltaic strandplains, large non-deltaic strandplains, small non-deltaic strandplains, large spits (cuspate forelands), small spits (flying spits, bay-mouth spits and tombolos) and barrier islands. A more comprehensive characterization of the factors controlling beach-ridge variability will improve our ability to recognize the sedimentary record of ancient of these systems. The proposed basic platform can be used to isolated different beach-ridge types and systems to facilitate future process and morphodynamic studies.  相似文献   

Approximate solutions of non-linear circular orbit relative motion in curvilinear coordinates     

Claudio Bombardelli  Juan Luis Gonzalo  Javier Roa 《Celestial Mechanics and Dynamical Astronomy》2017,127(1):49-66

A compact, time-explicit, approximate solution of the highly non-linear relative motion in curvilinear coordinates is provided under the assumption of circular orbit for the chief spacecraft. The rather compact, three-dimensional solution is obtained by algebraic manipulation of the individual Keplerian motions in curvilinear, rather than Cartesian coordinates, and provides analytical expressions for the secular, constant and periodic terms of each coordinate as a function of the initial relative motion conditions or relative orbital elements. Numerical test cases are conducted to show that the approximate solution can be effectively employed to extend the classical linear Clohessy–Wiltshire solution to include non-linear relative motion without significant loss of accuracy up to a limit of 0.4–0.45 in eccentricity and 40–45\(^\circ \) in relative inclination for the follower. A very simple, quadratic extension of the classical Clohessy–Wiltshire solution in curvilinear coordinates is also presented.  相似文献   

Quantification of cloud water interception in the canopy vegetation from fog gauge measurements          下载免费PDF全文

Christian Gonzalo Domínguez  Miguel Francisco García Vera  Cédric Chaumont  Julien Tournebize  Marcos Villacís  Noemi d'Ozouville  Sophie Violette 《水文研究》2017,31(18):3191-3205

With changes in climate looming, quantifying often‐overlooked components of the canopy water budget, such as cloud water interception (CWI), is increasingly important. Commonly, CWI quantification requires detailed continuous measurements, which is extremely challenging, especially when throughfall is included. In this study, we propose a simplified approach to estimate CWI using the Rutter‐type interception model, where CWI inputs in the canopy vegetation are proportional to fog interception measured by an artificial fog gauge. The model requires the continuous acquisition of meteorological variables as input and calibration datasets. Throughfall measurements below the forest are used only for calibration and validation of the model; thus, CWI estimates can be provided even after the cessation of throughfall monitoring. This approach provides an indirect and undemanding way to quantify CWI by vegetation and allows the identification of its controlling factors, which could be useful to the comparison of CWI in contrasting land covers. The method is applied on a 2‐year dataset collected in an endemic highland forest of San Cristobal Island (Galapagos). Our results show that CWI reaches 21% ± 6% of the total water input during the first year, and 9% ± 2% during the second one. These values represent 32% ± 10% and 17% ± 5% of water inputs during the cool foggy season of the first and second year, respectively. The difference between seasons is attributed to a lower fog liquid water during the second season.  相似文献   

Late Cenozoic brittle deformation in the Southern Patagonian Andes: Record of plate coupling/decoupling during variable subduction?          下载免费PDF全文

Vanesa Barberón  Christian Sue  Matías Ghiglione  Gonzalo Ronda  Eugenio Aragón 《地学学报》2018,30(4):296-309

The Andes of southern Patagonia experienced a Miocene shift towards faster and higher angle subduction followed by the approach and collision of the Chile oceanic ridge. We present a kinematic study characterizing palaeostress fields computed from brittle tectonics to better constrain upper crustal deformation during this complex scenario. Although previous studies already suggested variable kinematics, it is striking that in a long‐lasting subduction environment, the computed palaeostress tensors are mostly strike‐slip (55%), while 35% are extensional, and only 10% compressive which are concentrated along a main frontal thrust. Cross‐cutting relationships and synsedimentary deformation indicate that a long‐lived strike‐slip regime was punctuated by a lower Miocene extensional event in the foreland before the main compressional event. The results are discussed in contrasting geodynamic models of plate coupling/decoupling versus direction and rate of convergence of the subducting plate, to explain the main mechanisms that control back‐arc deformation.  相似文献   

Seismic microzoning of Arica and Iquique,Chile     

Alix Becerra  Luis Podestá  Roberto Monetta  Esteban Sáez  Felipe Leyton  Gonzalo Yañez 《Natural Hazards》2015,79(1):567-586

  相似文献   

Ground Penetrating Radar Applied to Monumental Stone Conservation: Application to the Rock Necropolis of San Vítor de Barxacova in NW Spain     

Solla  Mercedes  Buceta-Bruneti  Gonzalo  Elseicy  Ahmed  Nieto-Muñiz  Breogán 《Surveys in Geophysics》2022,43(5):1587-1606

Surveys in Geophysics - This paper deals with the application of the Ground Penetrating Radar (GPR) method in the assessment of stone monuments. Compilation of published works and a discussion of...  相似文献   

Improving the Wishart Synthetic Aperture Radar image classifications through Deterministic Simulated Annealing     

Francisco J. Sánchez-Lladó  Gonzalo Pajares  Carlos López-Martínez 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(6):845-857

This paper proposes the use of Deterministic Simulated Annealing (DSA) for Synthetic Aperture Radar (SAR) image classification for cluster refinement. We use the initial classification provided by the maximum-likelihood classifier based on the complex Wishart distribution that is then supplied to the DSA optimization approach. The goal is to improve the classification results obtained by the Wishart approach. The improvement is verified by computing a cluster separability coefficient. During the DSA optimization process, for each iteration and for each pixel, two consistency coefficients are computed taking into account two kinds of relations between the pixel under consideration and its neighbors. Based on these coefficients and on the information coming from the pixel itself, it is re-classified. Several experiments are carried out to verify that the proposed approach outperforms the Wishart strategy. We try to improve the classification results by considering the spatial influences received by a pixel through its neighbors. Finally, a link about the contribution of DSA to thematic mapping is also established.  相似文献   

Toward reduction of artifacts in fused images     

Mario Lillo-Saavedra  Consuelo Gonzalo  Octavio Lagos 《International Journal of Applied Earth Observation and Geoinformation》2011

Most fusion satellite image methodologies at pixel-level introduce false spatial details, i.e. artifacts, in the resulting fused images. In many cases, these artifacts appears because image fusion methods do not consider the differences in roughness or textural characteristics between different land covers. They only consider the digital values associated with single pixels. This effect increases as the spatial resolution image increases. To minimize this problem, we propose a new paradigm based on local measurements of the fractal dimension (FD). Fractal dimension maps (FDMs) are generated for each of the source images (panchromatic and each band of the multi-spectral images) with the box-counting algorithm and by applying a windowing process. The average of source image FDMs, previously indexed between 0 and 1, has been used for discrimination of different land covers present in satellite images. This paradigm has been applied through the fusion methodology based on the discrete wavelet transform (DWT), using the à trous algorithm (WAT). Two different scenes registered by optical sensors on board FORMOSAT-2 and IKONOS satellites were used to study the behaviour of the proposed methodology. The implementation of this approach, using the WAT method, allows adapting the fusion process to the roughness and shape of the regions present in the image to be fused. This improves the quality of the fused images and their classification results when compared with the original WAT method.  相似文献