Archivo Digital UPM
This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.
Materia = Geología
Mostrando recursos 1 - 20 de 926
Antarctic climate change and the environment: an update - Turner, John; Barrand, Nicholas E.; Bracegirdle, Thomas J.; Convey, Peter; Hodgson, Dominic A.; Jarvis, Martin; Jenkins, Adrian; Marshall, Gareth; Meredith, Michael P.; Roscoe, Howard; French, John; Goosse, Hugues; Guglielmin, Mauro; Gutt, Julian; Jacobs, Stan; Kennicutt II, Marlon C.; Masson-Delmotte, Valerie; Mayewski, Paul; Navarro Valero, Francisco Jose; Robinson, Sharon; Scambos, Ted; Sparrow, Mike; Summerhayes, Colin; Speer, Kevin; Klepikov, Alexander
We present an update of the "key points" from the Antarctic Climate Change and the Environment (ACCE) report that was published by the Scientific Committee on Antarctic Research (SCAR) in 2009. We summarise subsequent advances in knowledge concerning how the climates of the Antarctic and Southern Ocean have changed in the past, how they might change in the future, and examine the associated impacts on the marine and terrestrial biota. We also incorporate relevant material presented by SCAR to the Antarctic Treaty Consultative Meetings, and make use of emerging results that will form part of the Intergovernmental Panel on Climate...
La habitación subterránea en la Península Ibérica : investigación geológica - Sáenz Sanz, Clemente
La habitación rupestre en la Península Ibérica conforma un amplio conjunto de manifestaciones cuyos orígenes son difíciles de dilucidar. Existen conjuntos primitivos, posiblemente horadados durante la Antigüedad Clásica y Tardía, y otros que probablemente se originaron y excavaron en la Alta Edad Media, en los que se mezclan grupos de origen religioso y otros de probable uso defensivo. El conjunto peninsular es sin duda el más variado de Europa Occidental, pues recibió influencias árabes y usos de la cristiandad antigua, importados de Oriente Próximo, que por tanto relacionan estas manifestaciones con otras del arco mediterráneo.
La supervivencia del uso de...
Ground-penetrating radar surveys and ice volume estimates of Wedel Jarlsberg Land glaciers, Svalbard - Navarro Valero, Francisco Jose; Martín Español, Alba; Otero García, Jaime; Lapazaran Izargain, Javier Jesús; Vasilenko, Evgeniy; Grabiec, M.
We present volume calculations, with detailed error estimates, for eight glaciers on Wedel Jarlsberg Land, southern Spitsbergen, Svalbard, and compare them to those obtained from area-volume scaling relationships. The volume estimates are based upon a dense net of GPR-retrieved ice thickness data collected over several field campaigns spanning the period 2004-2011.
On the errors involved in the estimate of glacier ice volume from ice thickness data - Lapazaran Izargain, Javier Jesús; Martín Español, Alba; Otero García, Jaime; Navarro Valero, Francisco Jose
The assessment of the glacier thickness is one of the most widespread applications of radioglaciology, and is the basis for estimating the glacier volume. The accuracy of the measurement of ice thickness, the distribution of profiles over the glacier and the accuracy of the boundary delineation of the glacier are the most important factors determining the error in the evaluation of the glacier volume. The aim of this study is to get an accurate estimate of the error incurred in the estimate of glacier volume from GPR-retrieved ice-thickness data.
Modelling experiments of the variations of the calving front position of Hansbreen, Svalbard - Navarro Valero, Francisco Jose; Otero García, Jaime; Lapazaran Izargain, Javier Jesús; Robinson, Alexander
Hansbreen is a tidewater glacier in Svalbard, with grounded tongue, about 16 km in length and ca. 2.5 km in width at its tongue. The calving front position has shown, over the recent decades, a general retreating trend, often rather smooth but with some occasional abrupt changes. We apply a full-Stokes model of glacier dynamics, incorporating a crevasse-depth calving model, with the aim of reproducing the glacier front positions observed since 1936 and analyzing the sensitivity of the model to environmental parameters.
Preliminary results of the relation between ice viscosity and water content using an inverse method - Otero García, Jaime; Navarro Valero, Francisco Jose; Lapazaran Izargain, Javier Jesús
One of the outstanding problems of the modelling of temperate ice dynamics is the limited knowledge on the rheology of temperate ice and, in particular, on how the rate factor depends on the liquid water content. Though it is well known that the rate factor depends strongly on the water content, in practice the only available experimentally-based relationship is that by Duval (1977), which is only valid for water contents up to 1%. However, actual water contents found in temperate and polythermal glaciers are sometimes substantially larger.
Finite volume modelling of an icefield with subglacial lake - Bucchignani, Edoardo; Mansutti, Daniela; Navarro Valero, Francisco Jose; Otero García, Jaime; Glowacki, Piotr
Momentum, mass and energy balance laws provide the tools for the study of the evolution of an icefield covering a subglacial lake. The ice is described as a non-Newtonian fluid with a power-law constitutive relationship with temperature- and stress-dependent viscosity (Glen?s law) . The phase transition mechanisms at the air/ice and ice/water interfaces yield moving boundary formulations, and lake hydrodynamics requires equation reduction for treating the turbulence.
Species richness and similarity of vascular plants in the Spanish dehesas at two spatial scales - Roig Gomez, Sonia; García Del Barrio, Jose Manuel; Alonso Ponce, Rafael; Benavides, Raquel
Aims of study: The goals of this paper are to summarize and to compare plant species richness and floristic similarity at two spatial scales; mesohabitat (normal, eutrophic, and oligotrophic dehesas) and dehesa habitat; and to establish guidelines for conserving species diversity in dehesas. Area of study: We considered four dehesa sites in the western Peninsular Spain, located along a climatic and biogeographic gradient from north to south. Main results: Average alpha richness for mesohabitats was 75.6 species, and average alpha richness for dehesa sites was 146.3. Gamma richness assessed for the overall dehesa habitat was 340.0 species. The species richness...
Morphology and distribution of volcanic bombs in Caldera Quemada de Arriba (Lanzarote, Canary Islands): implications for volcanic hazard analysis - Galindo, I.; Romero, M.C.; Sánchez, N.; Dóniz, J.; Yepes Temiño, Jorge; Morales, J.M.; Becerril Carretero, Laura
Análisis del riesgo volcánico. We show the preliminary results of the study of 561 volcanic bombs ejected from a
pyroclastic cone during the 1730-1736 Timanfaya eruption (Lanzarote, Canary Islands). This cone
displays the highest concentration of big bombs (major axis higher than 1 m) of Timanfaya. More
than 560 bombs have been studied to calculate their reach. The results suggest that bombs of 1t have
a reach of 409 m, while bombs up to 28 t have a reach of 248 m. These data may be used to define
a security area once a vent has been opened, but also to calculate other data such...
Ice volume estimates from ground-penetrating radar surveys, Wedel Jarlsberg Land glaciers, Svalbard - Navarro Valero, Francisco Jose; Martín Español, Alba; Lapazaran Izargain, Javier Jesús; Grabiec, M.; Otero García, Jaime; Vasilenko, Evgeniy; Puczko, D.
One of the aims of the SvalGlac project is to obtain an improved estimate, with reliable error estimates, of the volume of Svalbard glaciers and their potential contribution to sea level rise. As part of this work, we present volume calculations, with detailed error estimates, for eight glaciers on Wedel Jarlsberg Land, southern Spitsbergen, Svalbard. The volume estimates are based upon a dense net of GPR-retrieved ice thickness data collected over several field campaigns spanning the period 2004-2011. The total area and volume of the ensemble are 502.9±18.6 km2 and 80.72±2.85 km3, respectively. Excluding Ariebreen (a tiny glacier, menor que...
Ice volume estimates from ground-penetrating radar surveys, western Nordenskiöld Land glaciers, Svalbard - Martín Español, Alba; Vasilenko, Evgeniy; Navarro Valero, Francisco Jose; Otero García, Jaime; Lapazaran Izargain, Javier Jesús; Lavrentiev, Ivan; Macheret, Y.Y.; Machío, F.; Glazovsky, A.
As part of ongoing work within the SvalGlac project aimed to obtain a reliable estimate of the total ice volume of Svalbard glaciers and their potential contribution to sea level rise, in this contribution we present volume calculations, with detailed error estimates, for ten glaciers on western Nordenskiöld Land, central Spitsbergen, Svalbard. The volume estimates are based upon a dense net of GPR-retrieved ice thickness data collected over several field campaigns spanning the period 1999-2012, all of them except one within 2010-2012. The total area and volume of the ensemble are 113.38±0.09 km2 and 10.439±0.185 km3, respectively, while the individual...
Local effects of depth-dependent water content of ice and snow and firn layers temperature on a conjectured subglacial lake below Amundsenisen Icefield (Svalbard) - Bucchignani, Edoardo; Mansutti, Daniela; Navarro Valero, Francisco Jose; Otero García, Jaime; Glowacki, Piotr
It is known that the Amundsenisen Icefield in Southern Spitzbergen (Svalbard achipelago) is temperate with an upper layer of snow and firn. It is an accumulation area and, though ice/water mass balance is clearly subject to time evolution, observation data on the long-term elevation changes over the past 40 years (Nuth et al., 2010) allow to assume constant icefield surface. Within our study of the plausibility of a subglacial lake (Glowacki et al., 2007), here, we focus on the sensitivity of the system to the thermal effect of the firn and snow layers.
Interaction between karstic aquifers and allogenic rivers: the aquifer of the national park of the ephemeral river Lobos Canyon (Spain) - Sanz Pérez, Eugenio; Menéndez Pidal de Navascués, Ignacio; Segovia Rosales, Rafael
A methodology is described for understanding the interaction of karstic aquifers with allogenic rivers, where little information is available. This methodology includes conventional hydrogen- ology methods tracer tests and measurements of flow into, out of and circulating within the karstic system. The method is designed to un- derstand the hydrogeological behaviour of a river in sufficient detail, given a short study pe- riod. The methodology is applied to a karstic system in Spain, obtaining useful, quantitative results for a hydrological year, such as an esti- mate of the water balance, differentiation be- tween autogenic and allogenic natural recharge, relationship and...
Sampling strategies using the "accumulation chamber" for monitoring geological storage of CO2 - Elío Medina, Javier De; Ortega Romero, Marcelo Fabián; Chacón Oreja, Enrique; Mazadiego Martínez, Luis Felipe; Grandía, Fidel
Fundación Ciudad de la Energía (CIUDEN) is carrying out a project of geological storage of CO2, where CO2 injection tests are planned in saline aquifers at a depth of 1500 m for scientiﬁc objectives and project demonstration. Before any CO2 is stored, it is necessary to determine the baseline ﬂux of CO2 in order to detect potential leakage during injection and post-injection monitoring. In November 2009 diffuse ﬂux measurements of CO2 using an accumulation chamber were made in the area selected by CIUDEN for geological storage, located in Hontomin province of Burgos (Spain). This paper presents the tests carried out...
¿Cómo se mide el estado de conservación de la dehesa? - Roig Gomez, Sonia; San Miguel Ayanz, Alfonso
La dehesa es un paisaje cultural y un sistema agrario de alto valor natural característico de la península Ibérica. Alberga altos niveles de biodiversidad y genera valiosos servicios de abastecimiento, regulación y culturales. Sin embargo, se enfrenta a graves amenazas, como los cambios de uso del suelo producidos en las últimas décadas. Por ello, la Unión Europea la ha incluido en el Anexo I de la Directiva 92/43/CEE, como tipo de hábitat de interés comunitario, lo que obliga a mantenerlo en un estado de conservación favorable y a emitir informes sobre su situación cada 6 años. Para ello resulta imprescindible...
Tree and grazing influence on herbaceous pasture diversity in the Dehesa agroforestry system - Lopez Sanchez, Aida; San Miguel Ayanz, Alfonso; Roig Gomez, Sonia; López Carrasco, Celia
Mediterranean Dehesas are one of the European natural habitat types of Community interest (43/92/EEC Directive), associated to high diversity levels and producer of important goods and services. In this work, tree contribution and grazing influence over pasture alpha diversity in a Dehesa in Central Spain was studied. We analyzed Richness and Shannon-Wiener (SW) indexes on herbaceous layer under 16 holms oak trees (64 sampling units distributed in two directions and in two distances to the trunk) distributed in four different grazing management zones (depending on species and stocking rate). Floristic composition by species or morphospecies and species abundance were analyzed...