1,720,974 research outputs found
Hydrologic impacts of surface elevation and spatial resolution in statistical correction approaches: case study of Flumendosa Basin, Italy
Full text linkThe role of surface elevation and spatial resolution in statistical correction approaches for temperature and precipitation forcing
is investigated using four global climate model (GCM) and regional climate model (RCM) combinations. A Mediterranean basin characterized by steep orography and prone to extreme flooding is chosen as a test case. For this aim, precipitation is statistically downscaled
using a parametric scheme for bias correction and high-resolution downscaling and a widely used nonparametric approach, with nominal
resolution equal to that of the GCM/RCM. Temperature fields are reprojected from climate model to terrain elevation at high resolution. The
response of the basin in terms of discharge, actual evapotranspiration, and leakage is simulated using the TOPographic Kinematic APproximation and Integration (TOPKAPI-X) model from 1951 to 2099 and at multiple spatial scales. To investigate the role of orography, simulations are run applying the downscaling schemes on a flat terrain. The results show that, independently of the size of the basin, the
elevation factor minimally affects the simulated hydrological response, whereas the effect of the spatial resolution of downscaled precipitation fields on the hydrological budget components is significant, and depends on the catchment size
Long-term rainfall risk from tropical cyclones in coastal areas
No full textWe develop a methodology for the frequency of extreme rainfall intensities caused by tropical cyclones (TCs) in coastal areas. The model does not account for landfall effects. This makes the developed framework best suited for open water sites and coastal areas with flat topography. The mean rainfall field associated with a TC with maximum tangential wind speed V[subscript max], radius of maximum winds R[subscript max], and translation speed Vt is obtained using a physically based model, whereas rainfall variability at both large scales (from storm to storm) and small scales (due to rainbands and local convection) is modeled statistically. The statistical component is estimated using precipitation radar data from the Tropical Rainfall Measuring Mission. Taylor's hypothesis is used to convert spatial rainfall intensity fluctuations to temporal fluctuations at a given location A. The combined physical-statistical model gives the distribution of the maximum rainfall intensity at A during an averaging period D for a TC with characteristics (V[subscript max], R[subscript max], V[subscript t]) that passes at a given distance from A. To illustrate the use of the model for long-term rainfall risk analysis, we formulate a recurrence model for tropical cyclones in the Gulf of Mexico that make landfall between longitudes 85° and 95°W. We then use the rainfall and recurrence models to assess the rainfall risk for New Orleans. For return periods of 100 years or more and long averaging durations (D around 12–24 h), tropical cyclones dominate over other rainfall event types, whereas the reverse is true for shorter return periods or shorter averaging durations.Alexander S. Onassis Public Benefit Foundation (Scholarship F-ZA 054/2005–2006
Prediction of air pollutants PM10 by ARBX(1) processes
No full textThis work was supported in part by projects MTM2015–71839–P and PGC2018-099549-B-I00 (co-funded by Feder funds), of the DGI, MINECO, Spain
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
HESS Opinions: "Climate, hydrology, energy, water: recognizing uncertainty and seeking sustainability"
No full textSince 1990 extensive funds have been spent on
research in climate change. Although Earth Sciences, including
climatology and hydrology, have benefited significantly,
progress has proved incommensurate with the effort
and funds, perhaps because these disciplines were perceived
as “tools” subservient to the needs of the climate change enterprise
rather than autonomous sciences. At the same time,
research was misleadingly focused more on the “symptom”,
i.e. the emission of greenhouse gases, than on the “illness”,
i.e. the unsustainability of fossil fuel-based energy production.
Unless energy saving and use of renewable resources
become the norm, there is a real risk of severe socioeconomic
crisis in the not-too-distant future. A framework for drastic
paradigm change is needed, in which water plays a central
role, due to its unique link to all forms of renewable energy,
from production (hydro and wave power) to storage (for
time-varying wind and solar sources), to biofuel production
(irrigation). The extended role of water should be considered
in parallel to its other uses, domestic, agricultural and
industrial. Hydrology, the science of water on Earth, must
move towards this new paradigm by radically rethinking its
fundamentals, which are unjustifiably trapped in the 19thcentury
myths of deterministic theories and the zeal to eliminate
uncertainty. Guidance is offered by modern statistical
and quantum physics, which reveal the intrinsic character of
uncertainty/entropy in nature, thus advancing towards a new
understanding and modelling of physical processes, which is
central to the effective use of renewable energy and water
resources
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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