1,720,997 research outputs found
Calibrazione di un modello idrologico semi-distribuito per l'analisi delle colate detritiche nel bacino del fiume Fella, Friuli-Venezia Giulia
No full textIl nord-est dell’Italia e, in particolare, la regione del Friuli-Venezia Giulia (FVG) sono caratterizzati da precipitazioni abbondanti ed intense che causano spesso fenomeni di colate detritiche. In particolare, una delle aree maggiormente colpite da colate detritiche riguarda la parte alto-orientale del bacino del fiume Fella, affluente del Tagliamento, che si estende sulle Alpi Giulie. Il lavoro mira a perseguire due obiettivi principali:
i) implementare un framework idro-morfodinamico per l'analisi delle colate detritiche innescate da intense precipitazioni;
ii) sfruttare, per la prima volta, la flessibilità del modello idrologico semi-distribuito GEOframe-NewAge per la simulazione di eventi pluviometrici ad alta risoluzione temporale (5 minuti)
Predicting peakflows in mountain river basins and data-scarce areas: a case study in northeastern Italy
No full textWe present a procedure to predict peakflows in mountain and ungauged basins, by addressing two challenges: fine temporal-resolution required to capture intense storms; scarcity of streamflow measurements needed to calibrate hydrological models. The study area is the Fella river basin at Pontebba and its upstream Uque sub-basin, northeastern Italian Julian-Alps. A non-stationary hydraulic model is combined with field measurements to derive rating curves at the downstream outlet which lacks discharge data. 5-minute rainfall series are exploited to predict hydrographs through a semi-distributed hydrological model, at continuous and event scales. The hydrological modelling on an ungauged basin is verified at the inner upstream outlet. Results indicated that the predictability of intense events is improved when a single storm is evaluated compared to a continuous hydrograph; event-based hydrographs at upstream outlet are well reproduced by the model calibrated with downstream data, thus allowing the use of the parameters in an ungauged basin
Calibrating and validating a semi-distributed hydrological model on a mountain basin.
No full textFrequent heavy precipitations characterize the northeastern Italy, where the Friuli Venezia Giulia (FVG) region is located. Mountain basins of the eastern Italian Alps are part of the upper Tagliamento river catchment, which is the major river system of the FVG region. The combination between precipitation regimes and geomorphological characteristics of the mountainous alpine environment makes this area highly susceptible to natural hazards induced by intense precipitation, with particular regard to debris flow and shallow diffusive landslides. A suitable modeling framework would include a chain constituted by a rainfall-runoff hydrological model and a hydro-morphodynamic model. In this paper we focus on the first step of the mentioned modeling chain by carrying out first a screening of data available, then the calibration and validation of a semi-distributed hydrological model in a sub-basin of the Fella river basin
Estimating the water budget components and their variability in a pre-alpine basin with JGrass-NewAGE
Full text linkThe estimation of water resources at basin scale requires modelling of all components of the hydrological system. Because of the great uncertainties associated with the estimation of each water cycle component and the large error in budget closure that results, water budget is rarely carried out explicitly. This paper fills the gap in providing a methodology for obtaining it routinely at daily and subdaily time scales. In this study, we use various strategies to improve water budget closure in a small basin of Italian Prealps. The specific objectives are: assessing the predictive performances of different Kriging methods to determine the most accurate precipitation estimates; using MODIS imagery data to assist in the separation of snowfall and rainfall; combining the Priestley-Taylor evapotranspiration model with the Budyko hypothesis to estimate at high resolution (in time and space) actual evapotranspiration (ET); using an appropriate calibration-validation strategy to forecast discharge spatially. For this, 18 years of spatial time series of precipitation, snow water equivalent, rainfall-runoff and ET at hourly time steps are simulated for the Posina River basin (Northeast Italy) using the JGrass-NewAGE system. Among the interpolation methods considered, local detrended kriging is seen to give the best performances in forecasting precipitation distribution. However, detrended Kriging gives better results in simulating discharges. The parameters optimized at the basin outlet over a five-year period show acceptable performances during the validation period at the outlet and at interior points of the basin. The use of the Budyko hypothesis to guide the ET estimation shows encouraging results, with less uncertainty than the values reported in literature. Aggregating at a long temporal scale, the mean annual water budget for the Posina River basin is about 1269 ± 372 mm (76.4%) runoff, 503.5 ± 35.5 mm (30%) evapotranspiration, and −50±129−50±129 mm (−−4.2%) basin storage from basin precipitation of 1730 ± 344 mm. The highest interannual variability is shown for precipitation, followed by discharge. Evapotranspiration shows less interannual variability and is less dependent on precipitation
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
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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