1,721,163 research outputs found
Long-term regional changes in inter-annual precipitation variability in the Campania Region, Southern Italy
No full textPrecipitation variability in space and time has been a focus of research over the past decades. The largest body of literature was essentially focused on long-term changes in average climates and in climate extremes. Analyses of the changes in the inter-annual climate variability (the year-to-year variability), which represent an index of climatic risk, received instead very less attention, but it represents an important issue in order to quantitatively measure the socioeconomic impact of climate change impact over water resources. In order to depict a general characterization of the long-term climate variability for the Campania region, located in Southern Italy within the Mediterranean basin, an analysis of the precipitation coefficient of variation, assumed as an index of inter-annual climate variability, was performed over the period 1918–2015 and compared with the annual precipitation regime and the intra-annual precipitation variability of the same region. The Mann–Kendall and the modified Mann–Kendall tests were applied to detect the sign and significance of the temporal changes and Sen’s test was applied to quantify the temporal changes in inter-annual variability. The results illustrated a generalized condition (73% of total stations) of statistically significant increase of inter-annual variability distributed almost over the whole analyzed area, even though the detected change appeared rather moderate in magnitude. The relationship between annual precipitation, intra-annual precipitation variability, and inter-annual precipitation variability was not clearly identified for the studied region, likely because of the characteristics of climatic homogeneity for the area under investigation. However, the comparative analyzes clearly showed how, if the variations in the annual precipitation regime and in the intra-annual precipitation variability are poorly significant (respectively for 9% and 11% of total station), changes in inter-annual precipitation variability are strongly marked over the studied region
From at-site to regional assessment of environmental flows and environmental flows variability in a Mediterranean environment
Full text linkStudy region: Data from 28 streamflow gauging stations located in the Campania Region, Southern Italy, were analysed. Study focus: The study was aimed at recommend regional methodologies for environmental flow (EF) and EF variability estimation for a climatological environment particularly affected by strong climate variability. Starting from an at-site statistical analysis of discharge data, a preliminary step where the quantification of EF average value, μ(Q95), and inter-annual variability, CV(Q95), was illustrated. A regional regression approach was then presented for the prediction of μ(Q95) and CV(Q95). New hydrological insights for the region: A step wise procedure highlighted the dominant hydrological variables and catchment attributes for EF prediction. Catchment area and mean annual daily discharge μ(Q) appeared strongly related to μ(Q95) whereas CV(Q95) was found to be dependent on the baseflow index and on precipitation variability. Regional predictions were evaluated on the base of the correlation coefficient and absolute average percentage errors. Prediction errors amounted to about 30 % and 17 % respectively in the case of μ(Q95) and CV(Q95). In the end, an implication for a fully regional approach, simply based on catchment attributes, also embedding the impact of hydrological variables, was presented. It showed clearly different performance capacity compared to the prediction based on the observed hydrological variables but not significantly lower
Baseflow index characterization in typical temperate to dry climates: conceptual analysis and simulation experiment to assess the relative role of climate forcing features and catchment geological settings
No full textLow-flow hydrological features are crucial for efficient development and integrated water resources management. Among others, the BaseFlow Index ‘BFI’ is one of the most important low-flow indices. Many studies have demonstrated that it is related to several topographic parameters, climate, vegetation and soil types and to catchment geology. With the aim to enhance the knowledge about the climate and catchment properties’ relative control on the ‘BFI’, an approach consisting of an empirical analysis, applied to a large area located in Southern Italy, characterized by a typical Mediterranean environment, is followed by a simulation experiment, considering climate settings, at the pan-European scale, typical of temperate to dry climate regimes. Main findings have revealed that (i) the correlation structure between the ‘BFI’ and the precipitation volume, at the annual scale, is affected by both climate variability and catchment properties; (ii) the ‘BFI’ variability is strongly conditioned by climate intra- and inter-annual variability; (iii) the major role is, however, assigned to the geological catchment features, with poorly and well-drained catchments behaving differently in response to similar climate forcing variability
Assessing the Relationship Between the Standardized Precipitation Evapotranspiration Index (SPEI) and the Normalized Difference Vegetation Index (NDVI) During 1985–2020 in a Mediterranean Area
No full text
SuDS as a climate change adaptation strategy: Scenario-based analysis for an urban catchment in northern Italy
Full text linkGoing 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
- …
