1,721,097 research outputs found
Comparing calibrated parameter sets of the SWAT model for the Scandinavian and Iberian peninsulas
No full textDifferent SWAT models have been set-up to predict water discharge at the European scale, applying an innovative modelling protocol that involves sensitivity analysis, multi-variable calibration and regionalization of the calibrated parameters. In this application, two large regions have been considered: the Scandinavian and the Iberian peninsulas, with the main objectives: (a) to study the spatial variation of calibrated parameter sets obtained for selected sub-basins, and (b) identification of the most relevant hydrological processes in each region. The results of the analysis highlight that snow processes are dominant in Scandinavia; groundwater processes are significant in both the Scandinavian and Iberian peninsulas, while lateral flow is not significant in either region. Calibrated soil hydraulic parameters have different ranges of values in each region, reflecting a difference in runoff-generating mechanisms between the two studied regions. The contribution of this analysis is the assessment of the main differences between hydrological processes across Europe and understanding of the major transport pathways for pollutants
Development of a continuous, physically-based distributed parameter, nonpoint source model
No full textANSWERS, an event-oriented, distributed parameter nonpoint source pollution model for simulating runoff and sediment transport was modified to develop a continuous nonpoint source model to simulate runoff, erosion, transport of dissolved and sediment-bound nutrients, and nutrient transformations. The model was developed for use by nonpoint source pollution managers to study the long-tenn effectiveness of best management practices (BMPs) in reducing runoff, sediment, and nutrient losses from agricultural watersheds.
The Holtan's infiltration equation used in the original version of ANSWERS was replaced by the physically-based Green-Ampt infiltration equation. Soil evaporation and plant transpiration were modeled separately using the Ritchie equation. If soil moisture exceeds field capacity, the model computes percolation based on the degree of soil saturation. Nutrient losses include nitrate, sediment-bound and dissolved ammonium; sediment-bound TKN, and sediment-bound and dissolved phosphorus. A linear equilibrium is assumed between dissolved and sediment-bound phases of ammonium and phosphorus. Nutrient loss is assumed to occur only from the upper cm of the soil profile.
The model simulates transformations and interactions between four nitrogen pools including stable organic N, active organic N, nitrate and ammonium. Transformations of nitrogen include mineralization simulated as a combination of ammonification and nitrification, denitrification, and plant uptake of ammonium and nitrate. The model maintains a dynamic equilibrium between stable and active organic N pools.Ph. D
Testing the Pearl Model in the Netherlands and Sweden
No full textThe Plant Protection Product Directive (91/414/EEC) stresses the need of validated models to calculate predicted environmental concentrations. The use of models has become an unavoidable step before pesticide registration. The main topic of the research presented here is the validation of the PEARL model for two well-instrumented sites located in the Netherlands and Sweden. First the water transport module was calibrated, and then the solute transport module, keeping unchanged the water transport parameters. The Dutch site is characterised by a sandy soil. PEARL predictions were very satisfactory for both soil moisture content, ground water level. Predictions for the tracer, bentazone and ethoprophos concentrations in the soil profile were also successful. The Swedish site is characterised by a structured clay soil. PEARL was successful in predicting soil moisture profiles and the draining water. PEARL performed well in predicting the soil concentration of bentazone at different depths, however it did not predict accurately solute concentration in the drainage water. A sensitivity analysis of the PEARL model performed on the Swedish site showed the greater importance of the pesticide degradation properties over the soil hydraulic propertiesJRC.H.5 - Rural, water and ecosystem resource
Evaluation of a land management based infiltration equation on rangelands
No full textDue to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references.Not availabl
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Towards a General Water Balance Assessment of Europe
Full text linkLarge proportions of water supply in European countries rely on groundwater resources, and many aquifers in water scarce regions are overexploited. Water management relies on reasonable information on water availability as well as on water demands by different sectors. Information on water availability and water needs are crucial to identify hot spots of quantitative pressures on water resources. This report focuses on estimating natural water availability across Europe. Simple water balance models were applied for an assessment of available water and potentials and limitations of their application are shown. Special emphasis is given to the role of groundwater in the water cycle and we explore ways to derive groundwater balance terms for large scale assessments. We further develop indicators of water quantity pressure relating water availability to water use and losses at different spatial scales. A short overview on the functioning of groundwater systems is given, highlights properties, processes and problems relevant for groundwater quantity and quality assessment. Some concepts to address groundwater issues at large scale are derived. The methodological part combines a general water balance assessment at large scale with more specific approaches to characterize groundwater systems and to quantify groundwater balance terms at large scale. Two different water balance modelling approaches are applied estimating the amount of water available for direct and subsurface runoff. The modelling approaches are compared to observed values and to each other. The available water is compared to water abstractions developing to indicators for human pressures on water resources. Focusing more specifically on groundwater systems, different methods to calculate baseflow and groundwater recharge are applied and compared and a prototype groundwater recharge map of Europe is presented. The report concludes with a synthesizing discussion of methods and results and an outlook on possible future studies. The individual studies have not yet been integrated into a common framework. Rather, they show various restrictions that require further research on various specific issues relevant for water management at European scale. The approaches laid out in this report and related reports provide a starting point for further development of screening approaches to be integrated in a common water resources assessment framework.JRC.H.5 - Rural, water and ecosystem resource
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
A spatially distributed assessment of water allocation in EU27 for Year 2000
Full text linkWater management relies not only on data on water availability, but also on data on water abstractions and demands. Hydrological modelling studies often neglect the impact of water abstractions and not all models are designed to handle abstractions. Given the various activities for European scale assessments made at the JRC and other institutions, it is desirable to have quantitative and spatially distributed background information on water abstractions, losses and returns to better judge the potential relevance of human abstractions on water quantity and to have reasonable estimates for modelling purposes.
The work presented in this report aims at evaluating the potential of readily available data from the OECD/EUROSTAT Joint Questionnaire on Inland Waters and relevant EUROSTAT data to support regionalized water balance assessments including human water abstraction and consumption. This report further document the methodological approaches to generate maps on water abstractions, losses and returns across the EU at 10x10km resolution.
Specific tasks documented in this report include:
• Modification and extension of available water abstraction data to generate consistent and complete datasets at national level.
• Spatial disaggregation of national data to regional and local (10x10km cell) level using proxy data and simulation results.
• Estimation of consumptive water losses and returns
• Comparison of water abstractions and losses to water availability and mapping of water resources pressure indicators.
The report is organized in three parts. Section 2 describes the data used in this assessment and the approaches to compile the specific data for the Atlas of water use and returns. Section 3 is an Atlas documenting and presenting the datasets. Section 4 is a general discussion of the approaches and results.JRC.H.5 - Rural, water and ecosystem resource
Water quality modeling in the Mediterranean river basins
No full textThe Mediterranean Sea is a semi-closed sea connected with the open sea through the Strait of Gibraltar. Due to the circulation pattern and the long residence time, the Mediterranean Sea is a sensitive environment to eutrophication and it is put at risk from direct and indirect impacts of human activities. In this study, a modified version of the model GREEN, originally developed for estimating nutrient loads from diffuse and point sources in Europe, was used based on a grid cell discretization (GREEN-Rgrid). The spatial resolution is 5 arc-minute resolution (9.2 km at the equator) and the model inputs consist of the latest and best available global data. The nitrate (N-NO3), total nitrogen (TN), orthophosphate (P-PO4) and total phosphorus (TP) loads were successfully calibrated for the period 2003-2007 (baseline). The nutrient source apportionment and retention in basins, rivers and lakes were also assessed. The baseline was then compared with two different scenarios: S1, a scenario of agricultural sources reduction that consists in reducing the nitrogen and phosphorus surplus by 50%; and S2, a scenario that consists in upgrading all wastewater treatment plants efficiency to tertiary treatment. The S1 scenario resulted most effective than S2 in reducing TN loads in the Mediterranean, whereas the most efficient scenario for reducing TP was S2.JRC.D.2 - Water and Marine Resource
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