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111.
The purpose of the present work is to study the hydrodynamic aspects in the Mar Piccolo, a coastal basin located on the northern side of the Gulf of Taranto in the Ionian Sea (Italy), by means of mathematical modelling and field measurements. The latter were assessed during three surveys carried out in the spring–summer of 2002. Collected data have been utilized as input by the 3-D Princeton Ocean Model, which is a sigma coordinate, free surface ocean model which was developed in the late 1970s by Blumberg and Mellor. Simulations in baroclinic condition were forced by a homogeneous and stationary wind field, a simple tidal wave, a constant outflow and vertical stratification of temperature and salinity. A comparison was made between the mathematical modelling results and the field measurements collected during the surveys, in terms of velocity. It was observed that during small tides, when the wind effect prevails over the stratification effect, the best model results were obtained for the most superficial layer and that superficial patterns reproduced by the model are more sensitive to wind direction than to stratification. On the contrary, when the wind effect decreases or the thermohaline effect rises, best results occurred in deeper layers. 相似文献
112.
Andrea?Tallarico Stefano?SantiniEmail author Michele?Dragoni 《Pure and Applied Geophysics》2005,162(12):2273-2298
The Central Apennines, Italy, are characterized by moderate seismic activity on normal faults, oriented in directions parallel
to the Apenninic chain. The subject of this study is the Umbria-Marche Apennines, a segment approximately 200-km long, where
three main seismic events occurred in the last three decades. The 1979 Norcia earthquake was a Mw = 5.8 event, taking place at the south end of the considered segment. The 1984 Gubbio earthquake was a Mw = 5.6 event which took place at the north end. The 1997-1998 Colfiorito sequence constituted 8 main shocks with magnitudes
Mw between 5 and 6 and epicenters located between the Gubbio and the Norcia earthquake areas. A model made of an elastic half-space
is considered, in which the seismic sources are represented by rectangular dislocations which have the appropriate values
of source parameters, and in which the static stress field produced by each event is calculated. The analysis of the Coulomb
stress change (ΔC) as a function of time shows that the coseismic stress transfer and fault interaction played an important role in the region
during the past three decades: 7 earthquakes of the 9 considered took place where ΔC>0. Such an interaction has been confirmed by the analysis of the aftershocks in the Colfiorito zone post September 26, 1997:
about the 61% of the aftershocks considered took place where ΔC>0. The comparison between the ΔCs due to the coseismic stress transfer and the rate ΔĊt due to the tectonic stress allows us to quantify the time advance of the earthquakes. The ΔCs pattern shows positive values in two areas that can be regarded as historical seismic gaps. 相似文献
113.
Michele Caputo 《Geophysical Journal International》1979,59(1):227-230
Summary. The effect of anelasticity on the periods of the Earth's free oscillation (toroidal modes) is examined in the light of several different studies leading to different results. The possibility of discrimination between the different analytic models for the anelasticity of the Earth's interior is discussed. A splitting of the spectral lines caused by Q is also suggested. 相似文献
114.
Michele Caputo 《Geophysical Journal International》1967,13(5):529-539
115.
Tamara T. Helfer Michael W. Regan Michele D. Thornley Tony Wong Kartik Sheth Stuart N. Vogel Douglas C.-J. Bock LEO Blitz Andy Harris 《Astrophysics and Space Science》2001,276(2-4):1131-1139
BIMA SONG is a systematic imaging study of the 3 mm CO J = 1 → 0molecular emission within the centres and discs of 44 nearby spiral galaxies on size scales of a few hundred parsecs
(6-9"). The overall goal of the survey is to study the role of molecular gas in the evolution of spiral galaxies. To this
end, BIMA SONG addresses 1) the distribution and physical conditions of the molecular gas in galactic discs and its relation
to star formation, 2) the effects of a stellar bar on the kinematics of molecular gas, including the possible inflow of gas
along a bar, and 3) the distribution and role of molecular gas in the central few hundred parsecs of active and quiescent
galaxies. The source list includes all (except M33and M31) 44 galaxies of Hubble types Sa–Sd, with declinations δ >−20°, visual magnitudes B < 11.0, velocities v
hel <2000 km s-1, and inclinations i < 70°. Beyond the specific scientific questions we will address, this survey will provide a unique database for astronomers who
study galaxies at all wavelengths.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
116.
117.
Runoff and nutrient transport by rivers were analysed in the Northern Adriatic continental shelf, in order to evaluate their interannual and multidecal variability, as well as their current contribution to determine freshwater and nutrient budgets in this marine region. During the years 2004-2007, the runoff in the basin (34.1-64.6 km3 yr−1) was highly imbalanced, being 84% of freshwater discharged along the western coast, because of the contributions of Po, Adige and Brenta rivers. In the northern and eastern sections of the coast, freshwater discharge by rivers was less important (10 and 6%, respectively), but not negligible in determining the oceanographic properties at sub-regional scales. The oscillations of the transport of biogenic elements (124-262×103 t N yr−1 for TN, 72-136×103 t N yr−1 for DIN, 4.5-11.1×103t P yr−1 for TP, 2.2-3.5×103 t P yr−1 for PO4 and 104-196×103 t Si yr−1 for SiO2) were strictly dependant to the differences in the annual runoff. A strong excess of N load in comparison to P load characterised all rivers, both in inorganic nutrient (DIN/PO4=37-418) and total (TN/TP=48-208) pools, particularly in the northern and eastern areas of the basin.The annual runoff showed significant oscillations for Po on multidecadal time scale, whereas a general decrease (−33%) was observed for the other N Adriatic rivers as the recent discharges were compared to those before the 1980s. During the dry years 2005-2007, a strong reduction of river water flows and nutrient loads was experienced by the N Adriatic ecosystem with respect to years characterised by medium-high regimes. An increased frequency of similar drought periods, due to ongoing climate changes or to a larger human usage of continental waters, would be easily able to significantly change the biogeochemistry of this basin. 相似文献
118.
Luciano Telesca Michele Lovallo Márta Marótiné Kiszely László Toth 《Acta Geophysica》2011,59(5):858-871
The Fisher-Shannon information (FS) plane, defined by the Fisher information measure (FIM), and the Shannon entropy power,
N
x
, is a robust tool for investigating the complex dynamics of time series. In the FS plane, earthquakes and quarry blasts measured
in Vértes Hills (Hungary) are significantly discriminated from each other. Furthermore, the results of the receiving-operating
characteristics (ROC) analysis reveal that FIM is a classifier more efficient than N
x
in discriminating earthquakes from quarry blasts. 相似文献
119.
Gerardo Herrera Davide Notti Juan Carlos Garc��a-Davalillo Oscar Mora Geraint Cooksley M��nica S��nchez Alain Arnaud Michele Crosetto 《Landslides》2011,8(2):195-206
This paper describes the use of the Stable Point Network technique, a Persistent Scatterer Interferometry SAR technique, for
the analysis of the Portalet landslide area (Central Pyrenees, Spain). For this purpose, different SAR datasets acquired by
ERS-1, ERS-2, ENVISAT and TerraSAR-X satellites have been analysed. The use of different SAR images acquired by satellite
radar sensors operating at different microwave lengths has allowed for a comparative assessment and illustration of the advantages
and disadvantages of these satellites for landslide detection and monitoring. In the introduction, differential interferometry
and the study area are briefly described. Then the specifics of the SPN processing and the results of the different datasets
are described and compared. In Analysis of the results: the Portalet landslide area, the Portalet landslide area is introduced
and the radar displacement measurements are analysed with available geo-information data. Additionally, X-band measurements
are compared with those gathered by a ground-based SAR for a previous project. Finally, the most relevant conclusions of this
work are discussed. 相似文献
120.
Daniele Spiga Gianpiero Tagliaferri Paolo Soffitta Oberto Citterio Stefano Basso Ronaldo Bellazzini Alessandro Brez Wolfgang Burkert Vadim Burwitz Enrico Costa Luca de Ruvo Ettore Del Monte Sergio Fabiani Gisela Hartner Benedikt Menz Massimo Minuti Fabio Muleri Giovanni Pareschi Michele Pinchera Alda Rubini Carmelo Sgrò Gloria Spandre 《Experimental Astronomy》2014,37(1):37-53
The Joint European X-ray Telescope (JET-X) was the core instrument of the Russian Spectrum-X- γ space observatory. It consisted of two identical soft X-ray (0.3–10 keV) telescopes with focusing optical modules having a measured angular resolution of nearly 15 arcsec. Soon after the payload completion, the mission was cancelled and the two optical flight modules (FM) were brought to the Brera Astronomical Observatory where they had been manufactured. After 16 years of storage, we have utilized the JET-X FM2 to test at the PANTER X-ray facility a prototype of a novel X-ray polarimetric telescope, using a Gas Pixel Detector (GPD) with polarimetric capabilities in the focal plane of the FM2. The GPD was developed by a collaboration between INFN-Pisa and INAF-IAPS. In the first phase of the test campaign, we have re-tested the FM2 at PANTER to have an up-to-date characterization in terms of angular resolution and effective area, while in the second part of the test the GPD has been placed in the focal plane of the FM2. In this paper we report the results of the tests of the sole FM2, using an unpolarized X-ray source, comparing the results with the calibration done in 1996. 相似文献