Linear discriminant analysis to describe the relationship between rainfall and landslides in Bogotá, Colombia   总被引：1，自引：0，他引：1  

Alfonso Mariano Ramos-Cañón  Luis Felipe Prada-Sarmiento  Mario Germán Trujillo-Vela  Juan Pablo Macías  Ana Carolina Santos-R 《Landslides》2016,13(4):671-681

Bogotá is located in the central Andean region of Colombia, which is frequently affected by landslide processes. These processes are mostly triggered during the rainy season in the city. This fact remarks the importance of determining what rain-derived parameters (e.g. intensity, antecedent rain, daily rain) are better related with the occurrence of landslides. For this purpose, the linear discriminant analysis (LDA), a technique derived from multivariate statistics, was used. The application of this type of analysis led to obtain simple mathematical functions that represent the probability of occurrence of landslides in Bogotá. The functions also allow to identify the most relevant variables derived from records of rainfall linked to the generation of landslides. A proof of concept using the proposed methodology was done using historic rainfall data from a 9-km² area of homogenous climatology and geomorphology in the south part of Bogotá. Landslides needed to be grouped for the LDA. Each one of these grouping categories represents landslides that occurred in similar geomorphologic conditions. Another set of events with no landslides was generated synthetically. Results of the proof of concept show that rainfall parameters such as normalized rainfall intensity I _MAP, normalized daily rainfall R _MAP and rainy-days normal RDN have the best statistical correlation with the landslides observed in the zone of analysis.  相似文献   

Effects of demand estimates on the evaluation and optimality of service centre locations     

Matej Cebecauer  Konštantín Rosina  Ľuboš Buzna 《International journal of geographical information science》2016,30(4):765-784

Public service systems, such as emergency health care, police or fire brigades, are critical for day-to-day functioning of the society. To design and operate these systems efficiently much data needs to be collected and properly utilised. Here, we use the OpenStreetMap (OSM) data to model the demand points (DPs), which approximate the geographical location of customers, and the road network, which is used to access or distribute services. We consider all inhabitants as customers, and therefore to estimate the demand, we use the available population grids. People are changing their location in the course of the day and thus the demand for services is changing accordingly. In this paper, we investigate how the used demand estimate affects the optimal design of a public service system. We calculate and compare efficient designs corresponding to two demand models, a night-time demand model when the majority of inhabitants rest at home and the demand model derived from the 24-hour average of the population density. We propose a simple measure to quantify the differences between population grids and we estimate how the size of differences affects the optimal structure of a public service system. Our analyses reveal that the efficiency of the service system is not only dependent on the placement strategy, but an inappropriate demand model has significant effects when designing a system as well as when evaluating its efficiency.  相似文献   

Mid and late Holocene forest fires and deforestation in the subalpine belt of the Iberian range,northern Spain     

José M. García-Ruiz  Yasmina Sanjuán  Graciela Gil-Romera  Penélope González-Sampériz  Santiago Beguería  José Arnáez  Paz Coba-Pérez  Amelia Gómez-Villar  Javier Álvarez-Martínez  Noemí Lana-Renault  Estela Pérez-Cardiel  Carlos López de Calle 《山地科学学报》2016,13(10):1760-1772

The conversion of subalpine forests into grasslands for pastoral use is a well-knownphenomenon, although for most mountain areas the timing of deforestation has not been determined. The presence of charcoal fragments in soil profiles affected by shallow landsliding enabled us to date the occurrence of fires and the periods of conversion ofsubalpine forest into grasslands in the Urbión Mountains, Iberian Range, Spain. We found that the treeline in the highest parts of the northwestern massifs of the Iberian Range(the Urbión, Demanda, Neila, and Cebollera massifs) is currently between 1500 and 1600 m a.s.l., probably because of pastoral use of the subalpine belt, whereas in the past it would have reached almost the highest divides(at approximately 2100–2200 m a.s.l.). The radiocarbon dates obtained indicate that the transformation of the subalpine belt occurred during the Late Neolithic, Chalcolithic, Bronze Age, Iron Age, and Middle Ages. Forest clearing was probably moderate during fires prior to the Middle Ages, as the small size of the sheep herds and the local character of the markets only required small clearings, and therefore more limited fires. Thus, it is likely that the forest recovered burnt areas in a few decades; this suggests the management of the forest and grasslands following a slash-andburn system. During the Middle and Modern Ages deforestation and grassland expansion affected most of the subalpine belt and coincided with the increasing prevalence of transhumance, as occurred in other mountains in the Iberian Peninsula(particularly the Pyrenees). Although the occurrence of shallow landslides following deforestation between the Neolithic and the Roman Period cannot be ruled out, the most extensive shallow landsliding processes would have occurred from the Middle Ages until recent times.  相似文献   

Exploring seven hundred years of transhumance,climate dynamic,fire and human activity through a historical mountain pass in central Spain     

José Antonio López-Sáez  Francisca Alba-Sánchez  Sandra Robles-López  Sebastián Pérez-Díaz  Daniel Abel-Schaad  Silvia Sabariego-Ruiz  Arthur Glais 《山地科学学报》2016,13(7):1139-1153

A high-altitude peat sequence from the heart of the Spanish Central System (Gredos range) was analysed through a multi-proxy approach to determine the sensitivity of high-mountain habitats to climate, fire and land use changes during the last seven hundred years, providing valuable insight into our understanding of the vegetation history and environmental changes in a mountain pass close to a traditional route of transhumance. The pollen data indicate that the vegetation was dominated by shrublands and grasslands with scattered pines in high-mountain areas, while in the valleys cereals, chestnut and olive trees were cultivated. Strong declines of high-mountain pines percentages are recorded at 1540, 1675, 1765, 1835 and 1925 cal AD, which may be related to increasing grazing activities and/or the occurrence of anthropogenic fires. The practice of mountain summer farming and transhumance deeply changed and redesigned the landscape of the high altitudes in central Spain (Gredos range) since the Middle Ages, although its dynamics was influenced in some way by climate variability of the past seven centuries.  相似文献   

Characterization of fresh and weathered petroleum for potential impacts to soil fertility     

C. M. Morales-Bautista  R. H. Adams  J. R. Hernández-Barajas  C. E. Lobato-García  J. G. Torres-Torres 《International Journal of Environmental Science and Technology》2016,13(11):2689-2696

In many petroleum-producing regions, there are not adequate controls to prevent pipeline breaks and spills, and thus soil is frequently contaminated with petroleum hydrocarbons. Different petroleum oil compounds may produce negative impacts on soil fertility. In this study, four fresh crudes, a weathered petroleum, and oils from bioremediated and burned sites were investigated (specific gravities 0.83–1.27). Fourier transform infrared spectroscopy revealed three predominant polar functional groups to be more plentiful in the heavier crudes. The relative abundance of these groups was used to calculate an index that was directly correlated with specific gravity (R ² = 0.9960) and the percent of asphaltene plus (polars + resins) fractions in the oil (R ² = 0.9643). This index correlated exponentially to the water repellency caused by petroleum in an alluvial soil (R ² = 0.9928). Furthermore, extra-heavy oil at a concentration of 10,000 ppm, the maximum allowable oil concentration in the soil that is within regulatory norms in many US states and other countries, and with a specific gravity >1.002, showed severe water repellency. This study presents an alternative for determining soil remediation criteria based on the API gravity of the oil rather than the C-range of the hydrocarbon mixtures, simplifying analytical methods and systematically studying the interaction between the kinds of petroleum mixtures and potential impacts to soil fertility.  相似文献   

Cuban zeolite for lead sorption: application for water decontamination and metal quantification in water using nondestructive techniques   总被引：1，自引：1，他引：0  

Y. Enamorado-Horrutiner  M. E. Villanueva-Tagle  M. Behar  G. Rodríguez-Fuentes  J. Ferraz Dias  M. S. Pomares-Alfonso 《International Journal of Environmental Science and Technology》2016,13(5):1245-1256

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Enhancement of a hypoplastic model for granular soil–structure interface behaviour     

H. Stutz  D. Mašín  F. Wuttke 《Acta Geotechnica》2016,11(6):1249-1261

Modelling of interfaces in geotechnical engineering is an important issue. Interfaces between structural elements (e.g., anchors, piles, tunnel linings) and soils are widely used in geotechnical engineering. The objective of this article is to propose an enhanced hypoplastic interface model that incorporates the in-plane stresses at the interface. To this aim, we develop a general approach to convert the existing hypoplastic model with a predefined limit state surface for sands into an interface model. This is achieved by adopting reduced stress and stretching vectors and redefining tensorial operations which can be used in the existing continuum model with few modifications. The enhanced interface model and the previous model are compared under constant-load, stiffness and volume conditions. The comparison is followed by a verification of two the approaches for modelling the different surface roughness. Subsequently, a validation between available experimental data from the literature versus simulations is presented. The new enhanced model gives improved predictions by the incorporation of in-plane stresses into the model formulation.  相似文献   

Spatial characterization of the seawater upconing process in a coastal Mediterranean aquifer (Plana de Castellón,Spain): evolution and controls     

Olga García-Menéndez  Ignacio Morell  Bruno J. Ballesteros  Arianna Renau-Pruñonosa  Alejandra Renau-Llorens  Mª Vicenta Esteller 《Environmental Earth Sciences》2016,75(9):728

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Temporal and spatial changes in soil micronutrients in managed <Emphasis Type="Italic">Nothofagus pumilio</Emphasis> forest of Tierra del Fuego,Argentina     

Romina Mansilla  Juan Carlos Nóvoa-Muñoz  Xabier Pontevedra-Pombal  Verónica Pancotto  Antía Gómez-Armesto  Julio Escobar  Alicia Moretto 《Environmental Earth Sciences》2016,75(9):738

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Multi-temporal InSAR evidence of ground subsidence induced by groundwater withdrawal: the Montellano aquifer (SW Spain)     

Ana Ruiz-Constán  Antonio M. Ruiz-Armenteros  Francisco Lamas-Fernández  Sergio Martos-Rosillo  J. Manuel Delgado  David P. S. Bekaert  Joaquim João Sousa  Antonio J. Gil  Miguel Caro Cuenca  Ramon F. Hanssen  Jesús Galindo-Zaldívar  Carlos Sanz de Galdeano 《Environmental Earth Sciences》2016,75(3):242

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