Worth of secondary data compared to piezometric data for the probabilistic assessment of radionuclide migration     

José E. Capilla  J. Rodrigo  J. J. Gómez-Hernández 《Stochastic Hydrology and Hydraulics》1998,12(3):171-190

A common approach for the performance assessment of radionuclide migration from a nuclear waste repository is by means of Monte-Carlo techniques. Multiple realizations of the parameters controlling radionuclide transport are generated and each one of these realizations is used in a numerical model to provide a transport prediction. The statistical analysis of all transport predictions is then used in performance assessment. In order to reduce the uncertainty on the predictions is necessary to incorporate as much information as possible in the generation of the parameter fields. In this regard, this paper focuses in the impact that conditioning the transmissivity fields to geophysical data and/or piezometric head data has on convective transport predictions in a two-dimensional heterogeneous formation. The Walker Lake data based is used to produce a heterogeneous log-transmissivity field with distinct non-Gaussian characteristics and a secondary variable that represents some geophysical attribute. In addition, the piezometric head field resulting from the steady-state solution of the groundwater flow equation is computed. These three reference fields are sampled to mimic a sampling campaign. Then, a series of Monte-Carlo exercises using different combinations of sampled data shows the relative worth of secondary data with respect to piezometric head data for transport predictions. The analysis shows that secondary data allows to reproduce the main spatial patterns of the reference transmissivity field and improves the mass transport predictions with respect to the case in which only transmissivity data is used. However, a few piezometric head measurements could be equally effective for the characterization of transport predictions.  相似文献   

Improving GSMaP V06 precipitation products over the Upper Tocantins River basin in the Brazilian Cerrado,based on local rain-gauge network     

Pereira  Rodrigo Moura  Bufon  Vinícius Bof  Maia  Felipe Cardoso Oliveira 《Theoretical and Applied Climatology》2022,148(3-4):1249-1260

Theoretical and Applied Climatology - Gridded precipitation products from remote sensing are currently available and could potentially enhance the use of precipitation data in regions with sparse...  相似文献   

The autonomous <Emphasis Type="Italic">Simpatico</Emphasis> system for real-time continuous water-quality and current velocity monitoring: examples of application in three Portuguese estuaries     

Erwan Garel  Susana Nunes  João Magalhães Neto  Rodrigo Fernandes  Ramiro Neves  João Carlos Marques  Óscar Ferreira 《Geo-Marine Letters》2009,29(5):331-341

This technical paper describes an autonomous recording system with remote data access for the continuous, long-term in situ monitoring of water quality and discharge, as well as current velocity. The Simpatico system has been recently deployed in three estuaries in Portugal (Mondego and Tagus in July 2007; Guadiana in March 2008), highly suitable to illustrate its multifaceted potential applications: surveillance of the effects of mitigation measures to combat eutrophication (lower Mondego Estuary); real-time implementation of boundary conditions for a water modelling system (upper Tagus Estuary); study of dam-induced impacts in terms of water quality, water discharge and sediment budgets (mouth of the Guadiana Estuary). An extract of recorded data serves as an example to discuss data reliability, as well as field maintenance of the system, with implications for labour and operational costs. The use of a new generation of copper-based anti-biofouling kits significantly reduced the need for field maintenance operations. Other examples of possible application of the system include the assessment of gas accumulation in coastal waters.  相似文献   

The Aguacaliente Fault,source of the Cartago 1910 destructive earthquake (Costa Rica)     

Jorge Alonso‐Henar  Walter Montero  José J. Martínez‐Díaz  José A. Álvarez‐Gómez  Juan M. Insua‐Arévalo  Wilfredo Rojas 《地学学报》2013,25(5):368-373

On 4 May 1910, the most destructive earthquake in the history of Costa Rica (Ms 6.4) destroyed the city of Cartago, a major city located in the Valle Central of Costa Rica. Using both palaeo‐seismological and morphotectonic analyses, we have found evidence that points to the Aguacaliente Fault (AF) as the source of this earthquake. This structure is a N100° E trending, strike‐slip fault situated to the south of Cartago and within a wide band of deformation. We excavated two trenches near Bermejo, south of Cartago. We found evidence of three surface ruptures within the last 1000 years on this fault. The age of the most recent rupture is consistent with the Cartago 1910 earthquake. The AF is a seismogenic source capable of producing large earthquakes (Mw 6.5–6.9) with an estimated recurrence interval of about 500 years.  相似文献   

Heterogeneity and homogeneity of Southern Brazilian beaches: A morphodynamic and statistical approach     

Pedro de Souza Pereira  Lauro Júlio Calliari  Rodrigo do Carmo Barletta 《Continental Shelf Research》2010,30(3-4):270-280

The characterization and beach morphodynamic differentiation along 620 km of Rio Grande do Sul state (RS) coastline has been principally done using beach profiles and their resulting morphometric parameters from the early 1990s through the present. The objective of the present work is to make a regional characterization, grouping the beaches with similar morphodynamic behavior along the RS coastline using multivariate statistical tools. For such purpose, a database containing topographic profiles and environment characteristics of 32 sites along the state coastline was built. A clustering analysis followed by a multidimensional scaling (MDS) analysis and an analysis of similarities (ANOSIM) was performed. The clustering and MDS results suggest that the data could be merged into six groups, one with dissipative tendencies, another with intermediate to reflective tendencies and three groups with intermediate characteristics. Each group showed distinct morphodynamic characteristics. Such differences are shown by the ANOSIM to be statistically significant. The three intermediate groups were differentiated in terms of beach mobility and percentage of medium-size sand, with higher mobility related to higher amounts of medium-size sand. The use of multivariate statistical techniques allowed a good differentiation between the RS beaches. Based on the results, it is suggested that the RS coastline can be segmented into seven different morphodynamic sectors. This approach can be used by management agencies to reduce potential oil spill impacts as well as decrease other beach hazards as well as for differentiate morphodynamical stages.  相似文献   

Spatial fisheries management: A framework for multi-objective qualitative assessment     

Sean Pascoe  Rodrigo Bustamante  Chris Wilcox  Mark Gibbs 《Ocean & Coastal Management》2009,52(2):130-138

In many circumstances, quantitative assessment of fisheries management options is either impossible due to data deficiencies or impractical given the size of the fishery. Quantitative analysis of spatial management options in particular is complicated, as information on spatial fleet and stock dynamics is often unavailable and spatial models are difficult to construct. In this paper, a qualitative framework is presented that aids in the analysis of alternative spatial management options in coastal fisheries. The framework combines expert opinion and the Analytic Hierarchy Process (AHP) to determine which options perform best taking into account the multiple objectives inherent in fisheries management.  相似文献   

Stochastic simulation of time-series models combined with geostatistics to predict water-table scenarios in a Guarani Aquifer System outcrop area, Brazil   总被引：3，自引：2，他引：1  

Rodrigo L. Manzione  Edson Wendland  Diego H. Tanikawa 《Hydrogeology Journal》2012,20(7):1239-1249

Stochastic methods based on time-series modeling combined with geostatistics can be useful tools to describe the variability of water-table levels in time and space and to account for uncertainty. Monitoring water-level networks can give information about the dynamic of the aquifer domain in both dimensions. Time-series modeling is an elegant way to treat monitoring data without the complexity of physical mechanistic models. Time-series model predictions can be interpolated spatially, with the spatial differences in water-table dynamics determined by the spatial variation in the system properties and the temporal variation driven by the dynamics of the inputs into the system. An integration of stochastic methods is presented, based on time-series modeling and geostatistics as a framework to predict water levels for decision making in groundwater management and land-use planning. The methodology is applied in a case study in a Guarani Aquifer System (GAS) outcrop area located in the southeastern part of Brazil. Communication of results in a clear and understandable form, via simulated scenarios, is discussed as an alternative, when translating scientific knowledge into applications of stochastic hydrogeology in large aquifers with limited monitoring network coverage like the GAS.  相似文献   

The ultraviolet survey of the Gould Belt: general properties of the Taurus star forming region     

Ana I. Gómez de Castro  Javier Lopez-Santiago  Paola Sestito  Victor Rodrigo Gudiel  Fatima López Martínez  Elisa de Castro  Manuel Cornide  Javier Yañez Gestoso 《Astrophysics and Space Science》2011,335(1):97-103

The Gould Belt is the local superassociation of star formation. The age of the Belt is some few 10⁷ yr, henceforth, its population is dominated by luminous young OB associations and low mass pre-main sequence stars. Attempts to unveil the low mass population have been run making use of the ROSAT all-sky survey. The all sky ultraviolet survey run by the GALaxy Evolution eXplorer (GALEX) maps several regions in the Belt. In this contribution, we present the preliminary analysis of the UV stellar population towards the Taurus region, one of the nearest and best studied regions of star formation.  相似文献   

Copper accumulation by bacteria and transfer to scallop larvae     

Miranda CD  Rojas R 《Marine pollution bulletin》2006,52(3):293-300

A bacterial copper-resistant strain was isolated from a hatchery-conditioned adult of the scallop Argopecten purpuratus and was identified as Vibrio sp. according to its physiological characteristics. The lowest concentration of Cu2+ required for its complete inhibition in VNSS medium was 50 microg ml(-1). The Vibrio strain was found to accumulate copper, exhibiting cellular and loosely bound copper levels of 201.14 and 493.21 microg g(-1) dry weight, respectively, after 24 h of incubation in VNSS medium supplemented with 15 microg ml(-1) of Cu2+, with cellular concentration factors of 10.17 and 14.35 after 12 and 24 h of exposure. When a scallop larvae culture was exposed to a concentration of 6.46 x 10(2) CFU ml(-1) of Cu-enriched Vibrio, they accumulated 20.42 +/- 1.12 and 30.96 +/- 1.85 microg Cu2+ g(-1) dry weight after 12 and 24 h, respectively. This study suggests that bacterial copper accumulation could be very active in marine environments increasing the occurrence of copper transfer to marine food chains.  相似文献   

The international outer planets watch atmospheres node database of giant-planet images     

R. Hueso  J. Legarreta  J.F. Rojas  A. Morgado 《Planetary and Space Science》2010,58(10):1152-74

The Atmospheres Node of the International Outer Planets Watch (IOPW, formerly known as International Jupiter Watch; Russell et al., 1990) intends to encourage and coordinate the imaging observations and study of the atmospheres of the Giant Planets. The main activity of the atmospheres node is to provide an interaction between the professional and amateur astronomical communities maintaining a large database of images of the giant planets (primarily Jupiter and Saturn but with increasing contributions of Uranus and Neptune too). The observational datasets of Jupiter and Saturn correspond to images obtained in the visible range (300 nm-1 μm), during the last decade, most of them performed by amateur observers. We here describe the organization and structure of the database as posted on the Internet and in particular the PVOL software (Planetary Virtual Observatory Laboratory) designed to manage the site in the spirit of the Virtual Observatory projects. We also describe with examples the important role of the amateur-professional collaboration in the study of the atmospheres of Jupiter and Saturn in an epoch of large telescopes and spacecraft observations of both planets.  相似文献