Centros UC

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Browsing Centros UC by browse.metadata.categoria "Ciencias de la tierra"

Now showing 1 - 12 of 12
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    A new aerobic chemolithoautotrophic arsenic oxidizing microorganism isolated from a high Andean watershed
    (2018) Anguita, Javiera M.; Rojas, Claudia; Pastén González, Pablo Arturo; Vargas Cucurella, Ignacio Tomás; CEDEUS (Chile)
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    A Volunteered Geographic Information Framework to Enable Bottom-Up Disaster Management Platforms
    (MDPI, 2015) Poorazizi, Mohammad Ebrahim; Hunter, Andrew J. S.; Steiniger, Stefan; CEDEUS (Chile)
    Recent disasters, such as the 2010 Haiti earthquake, have drawn attention to the potential role of citizens as active information producers. By using location-aware devices such as smartphones to collect geographic information in the form of geo-tagged text, photos, or videos, and sharing this information through online social media, such as Twitter, citizens create Volunteered Geographic Information (VGI). To effectively use this information for disaster management, we developed a VGI framework for the discovery of VGI. This framework consists of four components: (i) a VGI brokering module to provide a standard service interface to retrieve VGI from multiple resources based on spatial, temporal, and semantic parameters; (ii) a VGI quality control component, which employs semantic filtering and cross-referencing techniques to evaluate VGI; (iii) a VGI publisher module, which uses a service-based delivery mechanism to disseminate VGI, and (iv) a VGI discovery component to locate, browse, and query metadata about available VGI datasets. In a case study we employed a FOSS (Free and Open Source Software) strategy, open standards/specifications, and free/open data to show the utility of the framework. We demonstrate that the framework can facilitate data discovery for disaster management. The addition of quality metrics and a single aggregated source of relevant crisis VGI will allow users to make informed policy choices that could save lives, meet basic humanitarian needs earlier, and perhaps limit environmental and economic damage.
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    Ambient PM10 impacts brought by the extreme flooding event of March 24-26, 2015, in Copiapo, Chile
    (2018) Jorquera, Héctor; Maria Villalobos, Ana; Barraza Saavedra, Francisco Javier; CEDEUS (Chile)
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    An integrated analysis of the March 2015 Atacama floods
    (2016) Otárola, S.; Castro L.; Gironás León, Jorge Alfredo; Cienfuegos Carrasco, Rodrigo Alberto; Mao, Luca; Wilcox A.; Escauriaza Mesa, Cristián Rodrigo; Agredano, Roberto; Mignot E.; Zuazo V.; CEDEUS (Chile)
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    Coastal Evolution in a Wetland Affected by Large Tsunamigenic Earthquakes in South-Central Chile: Criteria for Integrated Coastal Management
    (MDPI, 2021) Martínez Reyes, Carolina Del Pilar; Sepúlveda-Zuñiga, Einer; Villagrán, Mauricio; Rojas, Octavio; Gómez, Matias; López, Pablo; Rojas Quezada, Carolina Alejandra; CEDEUS (Chile)
    The coastal evolution of the microtidal Tubul-Raqui wetland in south-central Chile (36 degrees S), which historically has been affected by large earthquakes and tsunamis, particularly the 1960 (Mw = 9.5) and 2010 (Mw = 8.8) subduction earthquakes and their associated tsunamis, is analyzed. Historical aerial photographs and topographic and bathymetric surveys from the 1961-2017 period, as well as salinity, sediment, and flora data obtained following the 2010 earthquake were used for comparison with data from prior to the event. A steady state of the shoreline was established, with an average erosion rate of -0.016 m/year in the 1961-2017 period. However, erosion predominated in the period between these two large earthquakes (1961-2009), with an average rate of -0.386 m/year. The wetland dried up, partially recovered saline intrusion a year later, and recovered the salinity conditions it had before the earthquake two years later. The postearthquake effects on the floristic composition were not significant, with the species Spartina densiflora, which presented a high tolerance to these types of changes, predominating. Moreover, 75 percent of the taxa in pre- and postearthquake conditions coincided, with the halophyte species Spartina densiflora, Sarcocornia fructicosa, and Cotula coronopifolia predominating, while the best-conserved community was Spartina-Sarcocornia association located in the saltmarsh. Seven years after the earthquake, the shoreline presented an accretion rate of 2.935 m/year; if the current tectonic conditions prevail, an erosive trend can be expected in the coming decades. The morphological variability and the changes associated with the shoreline in this wetland are strongly controlled by tectonic factors. Criteria aimed at integrated coastal management to promote its occupancy and use in accordance with its evolutionary dynamics are proposed.
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    Midday Boundary-Layer Collapse in the Altiplano Desert: The Combined Effect of Advection and Subsidence
    (2023) Aguirre Correa, Francisca; De Arellano, Jordi Vila-Guerau; Ronda, Reinder; Lobos Roco, Felipe Andrés; Suárez Poch, Francisco Ignacio; Hartogensis, Oscar; CEDEUS (Chile)
    Observations in the Altiplano region of the Atacama Desert show that the atmospheric boundary layer (ABL) suddenly collapses at noon. This rapid decrease occurs simultaneously to the entrance of a thermally driven, regional flow that causes a rise in wind speed and a marked temperature decrease. We identify the main drivers that cause the observed ABL collapse by using a land-atmosphere model. The free atmosphere lapse rate and regional forcings, such as advection of mass and cold air as well as subsidence, are first estimated by combining observations from a comprehensive field campaign and a regional model. Then, to disentangle the ABL collapse, we perform a suite of numerical experiments with increasing level of complexity: from only considering local land-atmosphere interactions, to systematically including the regional contributions of mass advection, cold air advection, and subsidence. Our results show that non-local processes related to the arrival of the regional flow are the main factors explaining the boundary-layer collapse. The advection of a shallower boundary layer (approximate to -250 m h(-1) at noon) causes an immediate decrease in the ABL height (h) at midday. This occurs simultaneously with the arrival of a cold air mass, which reaches a strength of approximate to -4 Kh(-1) at 1400 LT. These two external forcings become dominant over entrainment and surface processes that warm the atmosphere and increase h. As a consequence, the ABL growth is capped during the afternoon. Finally, a wind divergence of approximate to 8 x 10(-5) s(-1) contributes to the collapse by causing subsidence motions over the ABL from 1200 LT onward. Our findings show the relevance of treating large and small-scale processes as a continuum to be able to understand the ABL dynamics.
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    Observed trends and relationships between ENSO and standardized hydrometeorological drought indices in central Chile
    (2020) Oertel, Melanie; Meza, Francisco Javier; Gironás León, Jorge Alfredo; CEDEUS (Chile)
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    Saharan dust contributions to high hourly PM10 concentrations at a background station in Southwestern Europe
    (2023) Rodríguez, Jessika; García, María Ángeles; Pérez, Isidro A.; Jorquera, Héctor; CEDEUS (Chile)
    This paper presents a long-term analysis of ambient PM10 concentrations measured at a background station in Spain, using backward trajectories generated with the HYSPLIT model, together with the identification of synoptic patterns and a fuzzy clustering analysis, to identify the sources present and evaluate their relationship with meteorological variables such as wind speed and direction, temperature, and atmospheric pressure. Ambient PM10 presented maximum values during the summer with mean concentrations of approximately 14 µg m−3 for August, and minimum values during the winter with concentrations of 6 µg m−3 for January. The daily cycle presented two peaks—one in the morning and another in the afternoon—with this variability being associated with transport emissions. African air masses reached the study site extending vertically at least up to 2500 m.a.g.l, with a frequency of 43.5%, and are associated to a mean ground PM10 concentration of 41.3 µg m−3. During the episodes of Saharan intrusions, high pressures with unclassified synoptic patterns (U) prevailed over the Iberian Peninsula. Local, European, maritime and intermittent contributions were the four main sources of pollutants identified through fuzzy clustering analysis. These intermittent contributions are associated with Saharan dust intrusions, with a long-term average PM10 concentration of 1.7 µg m−3, which represents an important contribution of 11.2%. These sources affect seasonal variations of PM10 background concentrations, and reach their maximum when the greatest contributions of desert dust occur—mainly during the spring–summer months. These results provide useful information for future comparisons and environmental monitoring of PM10 levels
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    Spatio-temporal estimation of climatic variables for gap filling and record extension using Reanalysis data
    (2019) Morales Moraga, David Alejandro; Meza, Francisco Javier; Miranda, Marcelo; Gironás León, Jorge Alfredo; CEDEUS (Chile)
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    Using the Weather Research and Forecasting (WRF) Model for Precipitation Forecasting in an Andean Region with Complex Topography
    (2018) Yanez-Morroni, Gonzalo; Gironás León, Jorge Alfredo; Caneo, Marta; Delgado, Rodrigo; Garreaud, Rene; CEDEUS (Chile)
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    Water footprint and virtual water flows from the Global South: Foundations for sustainable agriculture in periods of drought
    (2023) Rojas Quezada, Carolina Alejandra; Novoa, Vanessa; Rojas, Octavio; Ahumada-Rudolph, Ramón; Arumí, José Luis; Munizaga, Juan; Cabrera-Pardo, Jaime R.; CEDEUS (Chile)
    Freshwater availability has decreased alarmingly worldwide, with agriculture playing a vital role in this trend. The assessment of the agricultural water footprint (WFagricultural) and virtual water flows (VWF) is fundamental not only in local water resources management and protection, but also in our understanding of the synergies between local water consumption and global markets. Thus, the WFagricultural – broken down into its components (blue, green, and gray) – of the leading 21 crops (grouped in fruit, legumes, cereals, and vegetables), grown in four basins with the most significant agricultural activity in central Chile was determined, estimated in two consecutive years 2017–2018. In addition, due to their great importance in exports, VWFs were assessed, establishing connections according to their origins and destinations. The results show that the green and gray water footprints increased significantly in the south-central basins, while blue water consumption increased in the basins of the central zone, reflecting an evident WFagricultural transition in accord with latitude and climate conditions. Furthermore, VWF showed an annual increase of 44 %, in about 116 destinations, with Asia, Europe, and North America being the preferred destinations, with annual variations of VWFblue- gray associated with increases in exports of apples, cherries, grapes, blueberries, and walnuts, market preferences and growing areas. The present study is an initial step toward sustainable agriculture in a commodity exporting country, one that is relevant in the exploitation of virtual water yet faces severe water deficit problems, distribution, and local water policies. Therefore, contributing to encouraging the efficiency and value of water in the process of a new institutional framework.