Integration of rainfall thresholds and susceptibility maps in the Emilia Romagna (Italy) regional-scale landslide warning system   总被引：2，自引：2，他引：0  

Samuele Segoni  Daniela Lagomarsino  Riccardo Fanti  Sandro Moretti  Nicola Casagli 《Landslides》2015,12(4):773-785

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Occurrence of brominated flame retardants, polycyclic musks, and chlorinated naphthalenes in seal blubber from Antarctica: Comparison to organochlorines     

Alessandra Schiavone  Kurunthachalam Kannan  Yuichi Horii  Silvano Focardi  Simonetta Corsolini 《Marine pollution bulletin》2009,58(9):1415-1419

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Numerical modeling of space-time wave extremes using WAVEWATCH III     

Francesco Barbariol  Jose-Henrique G. M. Alves  Alvise Benetazzo  Filippo Bergamasco  Luciana Bertotti  Sandro Carniel  Luigi Cavaleri  Yung Y. Chao  Arun Chawla  Antonio Ricchi  Mauro Sclavo  Hendrik Tolman 《Ocean Dynamics》2017,67(3-4):535-549

A novel implementation of parameters estimating the space-time wave extremes within the spectral wave model WAVEWATCH III (WW3) is presented. The new output parameters, available in WW3 version 5.16, rely on the theoretical model of Fedele (J Phys Oceanogr 42(9):1601-1615, 2012) extended by Benetazzo et al. (J Phys Oceanogr 45(9):2261–2275, 2015) to estimate the maximum second-order nonlinear crest height over a given space-time region. In order to assess the wave height associated to the maximum crest height and the maximum wave height (generally different in a broad-band stormy sea state), the linear quasi-determinism theory of Boccotti (2000) is considered. The new WW3 implementation is tested by simulating sea states and space-time extremes over the Mediterranean Sea (forced by the wind fields produced by the COSMO-ME atmospheric model). Model simulations are compared to space-time wave maxima observed on March 10th, 2014, in the northern Adriatic Sea (Italy), by a stereo camera system installed on-board the “Acqua Alta” oceanographic tower. Results show that modeled space-time extremes are in general agreement with observations. Differences are mostly ascribed to the accuracy of the wind forcing and, to a lesser extent, to the approximations introduced in the space-time extremes parameterizations. Model estimates are expected to be even more accurate over areas larger than the mean wavelength (for instance, the model grid size).  相似文献   

Seismic response of bridge piers on pile groups for different soil damping models and lumped parameter representations of the foundation     

Francisco González  Luis A. Padrón  Sandro Carbonari  Michele Morici  Juan J. Aznárez  Francesca Dezi  Graziano Leoni 《地震工程与结构动力学》2019,48(3):306-327

This paper presents a wide parametric study aimed at elucidating the influence, on the computed seismic response of bridge piers, of two related aspects of the model: (1) the adoption of the classical hysteretic or the causal Biot's damping models for the soil and (2) the use of two different lumped parameter models of different complexity and accuracy to approximate the impedances of the pile foundation. A total of 2072 cases, including different superstructures, pile foundations, soil deposits, and seismic input signals, are studied. The results are presented so that the influence of the different parameters involved in the analysis can be assessed. From an engineering point of view, both lumped parameter models provide, in general, sufficiently low errors. The choice of the most adequate model for each case will depend not only on the configuration of the structure and the soil-foundation system but also on the assumed soil damping model, whose influence on the computed seismic responses is relevant in many cases. The nonphysical behaviour provided by the classical hysteretic damping model for the soil at zero frequency generates issues in the process of fitting the impedance functions. It is also found that larger deck displacements are predicted by Biot's model due to the higher damping at low frequencies provided by the classical hysteretic damping model.  相似文献   

Soft proton flux on <Emphasis Type="Italic">ATHENA</Emphasis> focal plane and its impact on the magnetic diverter design     

Simone Lotti  Teresa Mineo  Christian Jacquey  Monica Laurenza  Valentina Fioretti  Gabriele Minervini  Giovanni Santin  Silvano Molendi  Tommaso Alberti  Paolo Dondero  Alfonso Mantero  Vladimir Ivanchencko  Claudio Macculi  Luigi Piro 《Experimental Astronomy》2018,45(3):411-428

The experience gained with the current generation of X-ray telescopes like Chandra and XMM-Newton has shown that low energy “soft” protons can pose a severe threat to the possibility to exploit scientific data, reducing the available exposure times by up to 50% and introducing a poorly reproducible background component. These soft protons are present in orbits outside the radiation belts and enter the mirrors, being concentrated towards the focal plane instruments, losing energy along their path and finally depositing their remaining energy in the detectors. Their contribution to the residual background will be even higher for ATHENA with respect to previous missions, given the much higher collecting area of the mirrors, even if the instruments will likely suffer no significant radiation damage from this particles flux. As a consequence this soft proton flux shall be damped with the use of a magnetic diverter to avoid excess background loading on the WFI or X-IFU instruments. We present here a first complete evaluation of this background component for the two focal plane instruments of the ATHENA mission in absence of a magnetic diverter, and derive the requirements for such device to reduce the soft protons induced background below the level required to enable the mission science. We estimate the soft proton flux expected in L2 for the interplanetary component and for the component generated locally by acceleration processes in the magnetotail. We produce a proton response matrix for each of the two instruments of ATHENA focal plane, exploiting two independent Monte Carlo simulations to estimate the optics concentration efficiency, and Geant4 simulations to evaluate the energy loss inside the radiation filters and deposited in the detector. With this modular approach we derive the expected fluxes and spectra for the soft protons component of the background. Finally, we calculate the specifics of a magnetic diverter able to reduce such flux below the required level for both X-IFU and WFI.  相似文献   

Investigating the impact of surface wave breaking on modeling the trajectories of drifters in the northern Adriatic Sea during a wind-storm event   总被引：4，自引：0，他引：4  

Sandro Carniel  John C. Warner  Jacopo Chiggiato  Mauro Sclavo 《Ocean Modelling》2009,30(2-3):225-239

An accurate numerical prediction of the oceanic upper layer velocity is a demanding requirement for many applications at sea and is a function of several near-surface processes that need to be incorporated in a numerical model. Among them, we assess the effects of vertical resolution, different vertical mixing parameterization (the so-called Generic Length Scale –GLS– set of k–ε, k–ω, gen, and the Mellor–Yamada), and surface roughness values on turbulent kinetic energy (k) injection from breaking waves.First, we modified the GLS turbulence closure formulation in the Regional Ocean Modeling System (ROMS) to incorporate the surface flux of turbulent kinetic energy due to wave breaking. Then, we applied the model to idealized test cases, exploring the sensitivity to the above mentioned factors. Last, the model was applied to a realistic situation in the Adriatic Sea driven by numerical meteorological forcings and river discharges. In this case, numerical drifters were released during an intense episode of Bora winds that occurred in mid-February 2003, and their trajectories compared to the displacement of satellite-tracked drifters deployed during the ADRIA02-03 sea-truth campaign.Results indicted that the inclusion of the wave breaking process helps improve the accuracy of the numerical simulations, subject to an increase in the typical value of the surface roughness z₀. Specifically, the best performance was obtained using α_CH = 56,000 in the Charnok formula, the wave breaking parameterization activated, k–ε as the turbulence closure model. With these options, the relative error with respect to the average distance of the drifter was about 25% (5.5 km/day). The most sensitive factors in the model were found to be the value of α_CH enhanced with respect to a standard value, followed by the adoption of wave breaking parameterization and the particular turbulence closure model selected.  相似文献   

The Radio and X-ray Mode-Switching Pulsar PSR B0943+10     

Sandro Mereghetti  Michela Rigoselli 《Journal of Astrophysics and Astronomy》2017,38(3):54

Observations obtained in the last years challenged the widespread notion that rotation-powered neutron stars are steady X-ray emitters. Besides a few allegedly rotation-powered neutron stars that showed ‘magnetar-like’ variability, a particularly interesting case is that of PSR B0943+10. Recent observations have shown that this pulsar, well studied in the radio band where it alternates between a bright and a quiescent mode, displays significant X-ray variations, anticorrelated in flux with the radio emission. The study of such synchronous radio/X-ray mode switching opens a new window to investigate the processes responsible for the pulsar radio and high-energy emission. Here we review the main X-ray properties of PSR B0943+10 derived from recent coordinated X-ray and radio observations.  相似文献   

Effects of 2,4,6-trinitrotoluene (TNT) on phase I and phase II biotransformation enzymes in European eel Anguilla anguilla (Linnaeus, 1758)     

Della Torre C  Corsi I  Arukwe A  Alcaro L  Amato E  Focardi S 《Marine environmental research》2008,66(1):9-11

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An atmosphere–ocean regional climate model for the Mediterranean area: assessment of a present climate simulation     

Vincenzo Artale  Sandro Calmanti  Adriana Carillo  Alessandro Dell’Aquila  Marine Herrmann  Giovanna Pisacane  Paolo M. Ruti  Gianmaria Sannino  Maria Vittoria Struglia  Filippo Giorgi  Xunqiang Bi  Jeremy S. Pal  Sara Rauscher 《Climate Dynamics》2010,35(5):721-740

We present an atmosphere–ocean regional climate model for the Mediterranean basin, called the PROTHEUS system, composed by the regional climate model RegCM3 as the atmospheric component and by a regional configuration of the MITgcm model as the oceanic component. The model is applied to an area encompassing the Mediterranean Sea and compared to a stand-alone version of its atmospheric component. An assessment of the model performances is done by using available observational datasets. Despite a persistent bias, the PROTHEUS system is able to capture the inter-annual variability of seasonal sea surface temperature (SST) and also the fine scale spatio-temporal evolution of observed SST anomalies, with spatial correlation as high as 0.7 during summer. The close inspection of a 10-day strong wind event during the summer of 2000 proves the capability of the PROTHEUS system to correctly describe the daily evolution of SST under strong air–sea interaction conditions. As a consequence of the model’s skill in reproducing observed SST and wind fields, we expect a reliable estimation of air–sea fluxes. The model skill in reproducing climatological land surface fields is in line with that of state of the art regional climate models.  相似文献   

Lithium speciation in aqueous fluids at high P and T studied by ab initio molecular dynamics and consequences for Li-isotope fractionation between minerals and fluids     

Sandro Jahn  Bernd Wunder 《Geochimica et cosmochimica acta》2009,73(18):2797-6123

Ab initio molecular dynamics simulations are performed to study the speciation changes in lithium bearing aqueous fluids at high temperature (T = 1000 K) and high pressures, P, between about 0.3 and 6.0 GPa. The simulations show a linear increase in Li coordination with fluid density, from 3.2 to about five in the considered pressure range. Towards low densities, associated LiF complexes are becoming increasingly stable, which is quantified by evaluating the dynamic behavior of the respective species. In the high-density region, HF complexes are observed. The differences in speciation may be related to structural changes of the solvent under compression. At a fluid density of 1.2 g/cm³, kinks in the pressure dependences of the oxygen–oxygen nearest neighbor distance and the oxygen–oxygen coordination are observed, which indicates a change in compaction mechanism. Assuming that the Li coordination difference between crystal and fluid is a major determinant for the isotopic fractionation between minerals and fluids, we expect only a small pressure dependence of the Li isotopic fractionation between Li bearing fluids and minerals. Our simulation results are consistent with experimental data that show reverse fractionation of ⁷Li between fluid and mineral, when Li is in tetrahedral instead of octahedral coordination in the crystal.  相似文献