Moisture recycling and the maximum of precipitation in spring in the Iberian Peninsula     

Alexandre Rios-Entenza  Gonzalo Miguez-Macho 《Climate Dynamics》2014,42(11-12):3207-3231

In the semiarid interior of the Iberian Peninsula, the topographic insulation from the surrounding seas promotes the role of internal sources of moisture and water recycling in the rainfall regime. In inland Iberia, the annual cycle of precipitation often has a distinctive peak in the springtime, when evapotranspiration (ET) is the highest, in contrast to the coastal areas, where it is more closely related to the external moisture availability and synoptic forcing, with a maximum in winter-autumn and a pronounced minimum in the summer. In this work we investigate the role of land surface water fluxes in the intensification of the hydrological cycle in the Iberian spring. We used data from 5 km resolution WRF-ARW model simulations over the Iberian Peninsula for eleven months of May (2000–2010). To bring out the effect of ET fluxes, we conducted experiments where ET water over land was removed from the system. Our findings indicate that the impact of ET on precipitation is on average very large (37 % increase). The impact is particularly strong in the interior north and northeast areas where the observed annual rainfall cycle has a peak in May, suggesting that the role of surface water fluxes is very important there. To investigate whether this role is as a water source or to amplify precipitation dynamics, we computed the recycling ratio analytically from the model data. In addition, we developed a procedure to quantify the amplification impact by comparing the recycling ratio and the relative change in precipitation between control and experiments with ET removed. Results show that the role of surface water fluxes on precipitation depends on large-scale forcing and moisture advection. When the synoptic forcing and moisture advection are strong, such as in fronts associated to Atlantic storms, the impact of ET fluxes is small. When there is potential for convection, as is commonly the case of late spring in the Iberian Peninsula, ET fluxes have a significant impact. Surface moisture fluxes moisten the boundary layer and increase moist static energy, strengthening convective processes, and their role goes from being a primary water source for precipitation (recycling) to have mostly an amplification effect as external moisture availability increases. Our findings show that for the eleven simulated May cases over the Iberian Peninsula, the role of ET fluxes in activating recycling is important and explains 27–58 % of their total impact on precipitation, depending on the method used to calculate the recycling ratio. This indicates that the complementary effect of ET on amplifying rainfall from external sources of moisture is comparable in magnitude to the recycling mechanism and important as well.  相似文献   

Regional-scale airborne electromagnetic surveying of the Yucatan karst aquifer (Mexico): geological and hydrogeological interpretation     

Bibi R. N. Gondwe  David Ottowitz  Robert Supper  Klaus Motschka  Gonzalo Merediz-Alonso  Peter Bauer-Gottwein 《Hydrogeology Journal》2012,20(7):1407-1425

Geometry and connectivity of high-permeability zones determine groundwater flow in karst aquifers. Efficient management of karst aquifers requires regional mapping of preferential flow paths. Remote-sensing technology provides tools to efficiently map the subsurface at such scales. Multi-spectral remote sensing imagery, shuttle radar topography data and frequency-domain airborne electromagnetic (AEM) survey data were used to map karst-aquifer structure on the Yucatan Peninsula, Mexico. Anomalous AEM responses correlated with topographic features and anomalous spectral reflectance of the terrain. One known preferential flow path, the Holbox fracture zone, showed lower bulk electrical resistivity than its surroundings in the AEM surveys. Anomalous structures delineated inland were sealed above by a low-resistivity layer (resistivity: 1–5 Ωm, thickness: 5–6?m). This layer was interpreted as ejecta from the Chicxulub impact (Cretaceous/Paleogene boundary), based on similar resistivity signatures found in borehole logs. Due to limited sensitivity of the AEM survey, the subsurface configuration beneath the low-resistivity layer could not be unambiguously determined. AEM measurements combined with remote-sensing data analysis provide a potentially powerful multi-scale methodology for structural mapping in karst aquifers on the Yucatan Peninsula and beyond.  相似文献   

Unusual Association of Skipjack Tunas Katsuwonus pelamis and a Longline Vessel     

Mucientes  Gonzalo  Vilas-Arrondo  Nair 《Ocean Science Journal》2021,56(1):96-98

Ocean Science Journal - Skipjack tuna were observed for the first time swimming in front of the bow of a fishing vessel during a tagging campaign in the North Atlantic. Video recordings show how...  相似文献   

An eddy tracking algorithm based on dynamical systems theory     

Daniel Conti  Alejandro Orfila  Evan Mason  Juan Manuel Sayol  Gonzalo Simarro  Salvador Balle 《Ocean Dynamics》2016,66(11):1415-1427

This work introduces a new method for ocean eddy detection that applies concepts from stationary dynamical systems theory. The method is composed of three steps: first, the centers of eddies are obtained from fixed points and their linear stability analysis; second, the size of the eddies is estimated from the vorticity between the eddy center and its neighboring fixed points, and, third, a tracking algorithm connects the different time frames. The tracking algorithm has been designed to avoid mismatching connections between eddies at different frames. Eddies are detected for the period between 1992 and 2012 using geostrophic velocities derived from AVISO altimetry and a new database is provided for the global ocean.  相似文献   

Population structure and connectivity in the Atlantic scleractinian coral Montastraea cavernosa (Linnaeus, 1767)     

Gretchen Goodbody‐Gringley  Robert M. Woollacott  Gonzalo Giribet 《Marine Ecology》2012,33(1):32-48

Coral reefs are increasingly threatened worldwide by a variety of biological and physical factors, including disease, bleaching and ocean acidification. Understanding levels of connectivity among widespread populations can assist in conservation efforts and the design of marine protected areas, as larval dispersal scales affect population demography. This study examined genetic connectivity and morphological variation of the broadcast spawning coral Montastraea cavernosa (L., 1767) among five locations in the Caribbean and Western Atlantic. Analysis of mtDNA and nuclear rRNA internal transcribed spacers, at both the local and regional scale, revealed that the majority of variation existed within locations rather than among them. Likewise, the majority of pairwise comparisons were non‐significant between sites and locations. These results suggest that moderate to high gene flow occurs within and among populations of M. cavernosa in the Western Atlantic. The phylogeographic signature and significant pairwise comparisons among several locations, however, indicate that populations are also partially maintained through self‐seeding and that gene flow may be restricted over large geographic distances. Additionally, while some anatomical variation is likely attributable to phenotypic plasticity, variations in skeletal morphology between Jamaica and other locations correspond with significant pairwise genetic distances and the presence of private sequence types (limited to a single location), suggesting selection to local environmental conditions.  相似文献   

Theoretical analysis and simulation for avoiding antenna oscillations without distributed resistance     

Gonzalo Garcia  Jos A. Uribe  David Ulloa  Rodrigo Zamora  Gino Casassa 《Journal of Applied Geophysics》2009,67(4):374

The so-called Wu and King antenna pattern is widely used in GPR because of its simple design and construction features. The main disadvantage is its limited efficiency due to transmitter energy losses which occur through lumped resistors. Based on the analysis of the electromagnetic field behaviour across the antenna, it is possible to replace the effect of the resistors by either storing the energy of the electric pulses, or damp them by means of one matched resistor, which will theoretically improve the efficiency of the antenna. In this paper we provide a theoretical analysis using a modified transmission line model together with simulation based on delayed potentials among other electromagnetic software, and measurement results using an impulse transmitter with fast MOSFET switches and a matched resistor that support this idea.  相似文献   

Morphodynamic interactions of continental shelf,beach and dunes: the Cabopino dune system in southern Mediterranean Spain     

Gonzalo Malvárez  Fatima Navas  Emilia Guisado-Pintado  Derek W.T. Jackson 《地球表面变化过程与地形》2019,44(8):1647-1658

The complex morphodynamic interactions between nearshore, shoreface and dune systems are usually simplified by studying these zones and their associated processes in isolation. However, the established relationships between each of them suggests that an integrated approach is required to examine the genesis, evolution and adaptation of the entire morphodynamic system. The Cabopino dune system in the southern Spanish Mediterranean Sea provides a clear example of a linked morphodynamic system in which a relatively large dune system has been generated and grown through the supply of sediments from an adjacent littoral supply environment. Here, we present a conceptual model of how the nearshore has provided suitable conditions for beach and dune development. We purport that synchronization of sediment activation in the marine and aeolian sections of the system have played a major role in this microtidal setting in which temporal aspects are not only tied to storm action, but to large sedimentary features moving alongshore. © 2019 John Wiley & Sons, Ltd.  相似文献   

Anatomy and facies distribution of terminal lobes in ephemeral fluvial successions: Jurassic Tordillo Formation,Neuquén Basin,Argentina     

Marina D. Coronel  Manuel F. Isla  Gonzalo D. Veiga  Nigel P. Mountney  Luca Colombera 《Sedimentology》2020,67(5):2596-2624

In terminal fluvial-fan systems, characteristic proximal to distal variations in sedimentary architectures are recognized to arise from progressive downstream loss of water discharge related to both infiltration and evaporation. This work aims to elucidate downstream trends in facies and architecture across the medial and distal zones of terminal-fan systems, which record transitions from deposits of channel elements to lobe-like and sheet-like elements. This is achieved via a detailed characterization of ancient ephemeral fluvial deposits of the well-exposed Kimmeridgian Tordillo Formation (Neuquén Basin, Argentina). The fine sand-prone and silt-prone succession associated with the medial to distal sectors of the system has been studied to understand relationships between depositional processes and resulting architectures. Facies and architectural-element analyses, and quantification of resulting sedimentological data at multiple scales, have been undertaken to characterize sedimentary facies, facies transitions, bed types, architectural elements and larger-scale architectural styles. Eight bed types with distinct internal facies transitions are defined and interpreted in terms of different types of flood events. Channelized and non-channelized architectural elements are defined based on their constituent bed types and their external geometry. The most common elements are terminal lobes, which are composite bodies within which largely unconfined sandy deposits are stacked in a compensational manner; a hierarchical arrangement of internal components is recognized. Proximal feeder-channel avulsion events likely controlled the evolution of terminal-lobe elements and their spatiotemporal shifts. Stratigraphic relations between architectural elements record system-wide trends, whereby a proximal sector dominated by channel elements passes downstream via a gradational transition to a medial sector dominated by sandy terminal-lobe elements, which in turn passes further downstream to a distal sector dominated by silty terminal lobe-margin and fringing deposits. This work enhances current understanding of the stratigraphic record of terminal fluvial systems at multiple scales, and provides insight that can be applied to predict the facies and architectural complexity of terminal fluvial successions.  相似文献   

Social multi-criteria evaluation as a decision support tool for integrated coastal zone management     

Eneko Garmendia  Gonzalo Gamboa  Javier Franco  Joxe Mikel Garmendia  Pedro Liria  Marta Olazabal 《Ocean & Coastal Management》2010,53(7):385-403

Traditional top-down and technocratic approaches seem to be insufficient to tackle the many conflicts related to the sustainable use of natural resources. At the same time, reductionist and mono-disciplinary approaches lack the capacity to capture the complex interactions within evolving socio-ecological systems. Coastal zone management is an area that provides a clear example of such difficulties. In this paper we explore the scope of a participatory integrated assessment process, known as Social Multi-Criteria Evaluation (SMCE), in the context of Integrated Coastal Zone Management (ICZM). Through a two-year collaborative research process, between an interdisciplinary group of researchers and a diverse group of stakeholders in the Urdaibai Estuary (a Biosphere Reserve in the Basque Country, Northern Spain), we show that improving the integration of diverse expertise and values can lead, through a mutual learning process, to the definition of relevant policy options and sound decisions in the face of complexity, value conflict and unavoidable uncertainty.  相似文献   

Assessment of the oil source-rock potential of the Pedregoso Formation (Early Miocene) in the Falcón Basin of northwestern Venezuela     

Jean Carlos Montero-Serrano  Manuel Martínez  Armelle Riboulleau  Nicolas Tribovillard  Gonzalo Márquez  José Vicente Gutiérrez-Martín 《Marine and Petroleum Geology》2010

The early Miocene Pedregoso Formation is one of the numerous formations rich in organic matter within the stratigraphic record of the Urumaco Trough, in the central area of the Falcón Basin. Due to its lithological characteristics and stratigraphic position, this formation is of great interest regarding the basin's petroliferous systems. The evaluation of various inorganic and organic geochemical parameters indicates that the organic matter is primarily of marine origin, deposited in a marine carbonate environment typical of reefal systems, under oxic-to-dysoxic conditions. The low variability in the TOC concentrations and in the distributions of the biomarkers extracted from the samples suggests that the paleoenvironmental conditions and the organic-matter supply remained approximately constant throughout the sedimentation of this unit. The Pedregoso type-II organic matter (marine origin) and initial organic richness value (∼1.8%) suggest that this unit has probably generated hydrocarbons within the Urumaco Trough. However, present-day thermal maturity parameters reveal that the Pedregoso organic matter is overmature (dry gas window), indicating that this unit is only capable to generate gas. In addition, the geothermal gradient, maturity parameters, and the maximum paleotemperature estimated in this study suggest that the Pedregoso Formation reached a maximum burial depth the ∼6.5 km, consistent with the value obtained from data of stratigraphic thickness in the Urumaco Trough. This implies that the thermal anomaly that affected the basin during the Late Eocene–Early Miocene did not reach the central part of the basin, and therefore, the organic matter maturation in this unit is due to the sedimentary burial.  相似文献