1,720,983 research outputs found
Hydrological signals in height and gravity in northeastern Italy inferred from principal components analysis
No full textThis work describes a study of GPS heights, gravity and hydrological time series collected by stations located in northeastern Italy. During the last 12 years, changes in the long-term behaviors of the GPS heights and gravity time series are observed. In particular, starting in 2004-2005, a height increase is observed over the whole area. The temporal and spatial variability of these parameters has been studied as well as those of key hydrological variables, namely precipitation, hydrological balance and water table by using the Empirical Orthogonal Functions (EOF) analysis. The coupled variability between the GPS heights and the hydrological balance and precipitation data has been investigated by means of the Singular Value Decomposition (SVD) approach. Significant common patterns in the spatial and temporal variability of these parameters have been recognized. In particular, hydrology-induced variations are clearly observable starting in 2002-2003 in the southern part of the Po Plain for the longest time series, and from 2004-2005 over the whole area. These findings, obtained by means of purely mathematical approaches, are supported by sound physical interpretation suggesting that the climate-related fluctuations in the regional/local hydrological regime are one of the main contributors to the observed variations. A regional scale signal has been identified in the GPS station heights; it is characterized by the opposite behavior of the southern and northern stations in response to the hydrological forcing. At Medicina, in the southern Po Plain, the EOF analysis has shown a marked common signal between the GPS heights and the Superconducting Gravimeter (SG) data both over the long and the short period
Observing and assessing seasonal non-tidal ocean loading through ocean, continuous GPS and gravity data in the Adriatic area
No full text
Estimate and Modeling of Vertical Ground Displacements by Space and Terrestrial Techniques in the Northern Adriatic, Italy
No full textThe Northern Adriatic area, in Italy, including coastal regions, is affected by high rates of natural subsidence greatly enhanced, during last century, by anthropogenic components mainly due to ground fluid exploitation. To measure and model vertical crustal movements is of major importance for the presence of natural lowlands and coastal lowlands which are exposed to the risks of flooding events due to river overflow or to the occurrence of extreme storm events. Sea-level rise resulting from increasing global temperature is an additional threat to this region. A network of permanent GPS stations, extending from the southern Po River Plain to the area around Venice, is in place since several years. At most of the stations, in addition to GPS, other geodetic observation techniques such as gravity and InSAR allow for validation of the individual time series, for continuous monitoring in space and time of vertical movements by combining GPS and InSAR, and for a better understanding of the geodynamical processes in the area. Three tide gauge stations with centennial time series, co-located with the GPS systems, are available. The vertical land movements can be removed from the tide gauge records in order to derive absolute sea-level time series. A comparison with satellite altimetry data is performed at the three coastal stations, although this is not an easy task because the satellite data are limited due to the narrow shape of the Adriatic basin. The GPS network data have been re-analyzed by using ITRF2005 and the vertical rates have been estimated. These results are compared to those provided by absolute and relative gravimetry and InSAR data
Vertical Crustal Movements and Sea-level Changes in the Northern Adriatic
No full textThe Department of Physics of the University of Bologna (UNIBO), the Consorzio Venezia Nuova, sole agent of the Magistrato alle Acque di Venezia for the managemente of the Venice lagoon environment (MAV), the Italian National Agency for Environmental Protection and Technical Services (APAT), have recently started joint projects to determine and study vertical crustal movements and sea-level fluctuations in the northern Adriatic area where the natural subsidence has been enhanced by anthropogenic components during last century. The combination of the permanent GPS stations belonging to UNIBO and of those of the MAV and APAT constitutes a basic network for the study of land subsidence in the northern Adriatic. We have studied and applied a combined observational strategy for monitoring and reliably identifying both seasonal and log-term crustal movements, namely height variations/changes. The strategy adopted is based on a multidisciplinary approach that combines the information provided by GPS, InSAR and terrestrial and space gravimetry. The results of these different techniques are compared and combined in a study on land subsidence in the southeastern Po Plain and the northern Adriatic coast, in Italy. The sea-level time series of the Marina di Ravenna, Venice and Trieste tide gauge stations are compared to the Topex/Poseidon satellite altimetry sea-level elevation and to the GPS height and InSAR long-term trends at the same stations
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
- …
