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71.
FLaIR and SUSHI: two mathematical models for early warning of landslides induced by rainfall 总被引:8,自引:7,他引:1
The development of Early Warning Systems in recent years has assumed an increasingly important role in landslide risk mitigation.
In this context, the main topic is the relationship between rainfall and the incidence of landslides. In this paper, we focus
our attention on the analysis of mathematical models capable of simulating triggering conditions. These fall into two broad
categories: hydrological models and complete models. Generally, hydrological models comprise simple empirical relationships
linking antecedent precipitation to the time that the landslide occurs; the latter consist of more complex expressions that
take several components into account, including specific site conditions, mechanical, hydraulic and physical soil properties,
local seepage conditions, and the contribution of these to soil strength. In a review of the most important models proposed
in the technical and international literature, we have outlined their most meaningful and salient aspects. In particular,
the Forecasting of Landslides Induced by Rainfall (FLaIR) and the Saturated Unsaturated Simulation for Hillslope Instability
(SUSHI) models, developed by the authors, are discussed. FLaIR is a hydrological model based on the identification of a mobility
function dependent on landslide characteristics and antecedent rainfall, correlated to the probability of a slide occurring.
SUSHI is a complete model for describing hydraulic phenomena at slope scale, incorporating Darcian saturated flow, with particular
emphasis on spatial–temporal changes in subsoil pore pressure. It comprises a hydraulic module for analysing the circulation
of water from rainfall infiltration in saturated and nonsaturated layers in non-stationary conditions and a geotechnical slope
stability module based on Limit Equilibrium Methods. The paper also includes some examples of these models’ applications in
the framework of early warning systems in Italy. 相似文献
72.
Giorgio Budillon Pasquale Castagno Stefano AlianiGiancarlo Spezie Laurie Padman 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(10):1002-1018
We use hydrological and current meter data collected in the Ross Sea, Antarctica between 1995 and 2006 to describe the spatial and temporal variability of water masses involved in the production of Antarctic Bottom Water (AABW). Data were collected in two regions of known outflows of dense shelf water in this region; the Drygalski Trough (DT) and the Glomar-Challenger Trough (GCT). Dense shelf water just inshore of the shelf break is dominated by High Salinity Shelf Water (HSSW) in the DT and Ice Shelf Water (ISW) in the GCT. The HSSW in the northern DT freshened by ∼0.06 in 11 y, while the ISW in the northern GCT freshened by ∼0.04 in 8 y and warmed by ∼0.04 °C in 11 y, dominated by a rapid warming during austral summer 2001/02. The Antarctic Slope Front separating the warm Circumpolar Deep Water (CDW) from the shelf waters is more stable near GCT than near DT, with CDW and mixing products being found on the outer DT shelf but not on the outer GCT shelf. The different source waters and mixing processes at the two sites lead to production of AABW with different thermohaline characteristics in the central and western Ross Sea. Multi-year time series of hydrography and currents at long-term moorings within 100 km of the shelf break in both troughs confirm the interannual signals in the dense shelf water and reveal the seasonal cycle of water mass properties. Near the DT the HSSW salinities experienced maxima in March/April and minima in September/October. The ISW in the GCT is warmest in March/April and coolest between August and October. Mooring data also demonstrate significant high-frequency variability associated with tides and other processes. Wavelet analysis of near-bottom moored sensors sampling the dense water cascade over the continental slope west of the GCT shows intermittent energetic pulses of cold, dense water with periods from ∼32 h to ∼5 days. 相似文献
73.
Massimiliano De Pasquale Dirk Grupe T. S. Poole A. A. Breeveld S. Zane S. R. Rosen M. J. Page K. O. Mason D. N. Burrows H. A. Krimm N. Gehrels J. A. Nousek P. W. A. Roming S. Kobayashi B. Zhang 《Monthly notices of the Royal Astronomical Society》2006,370(4):1859-1866
We present the results of X-ray and optical observations of GRB 050712 performed by Swift . The X-ray light curve of this burst exhibits episodes of flares in the first 1000 s, the same epoch at which the UVOT detected an optical counterpart. A shallow X-ray decay, with a decay slope of α=−0.73 , followed and lasted ∼70 ks. This behaviour can be explained in terms of activity of the gamma-ray burst 'inner engine', with the possibility that the last flare is caused by the interaction of the ejecta with the surrounding medium.
We also find interesting spectral parameters for the X-ray emission. In particular, data suggest the presence of an intrinsic absorption in the first 1000 s, which can be explained if circumburst medium clouds lie along the line of sight. 相似文献
We also find interesting spectral parameters for the X-ray emission. In particular, data suggest the presence of an intrinsic absorption in the first 1000 s, which can be explained if circumburst medium clouds lie along the line of sight. 相似文献
74.
Massimiliano De Pasquale y P. Beardmore S. D. Barthelmy P. Boyd D. N. Burrows R. Fink N. Gehrels S. Kobayashi K. O. Mason R. McNought J. A. Nousek K. L. Page D. M. Palmer B. A. Peterson P. A. Price J. Rich P. Roming S. R. Rosen T. Sakamoto B. P. Schmidt J. Tueller A. A. Wells S. Zane B. Zhang H. Ziaeepour 《Monthly notices of the Royal Astronomical Society》2006,365(3):1031-1038
75.
76.
Stefano Gabici Felix A. Aharonian Pasquale Blasi 《Astrophysics and Space Science》2007,309(1-4):365-371
It is believed that the observed diffuse gamma-ray emission from the galactic plane is the result of interactions between
cosmic rays and the interstellar gas. Such emission can be amplified if cosmic rays penetrate into dense molecular clouds.
The propagation of cosmic rays inside a molecular cloud has been studied assuming an arbitrary energy and space dependent
diffusion coefficient. If the diffusion coefficient inside the cloud is significantly smaller compared to the average one
derived for the galactic disk, the observed gamma-ray spectrum appears harder than the cosmic ray spectrum, mainly due to
the slower penetration of the low energy particles towards the core of the cloud. This may produce a great variety of gamma-ray
spectra. 相似文献
77.
P. Schady M. De Pasquale M. J. Page L. Vetere S. B. Pandey X. Y. Wang J. Cummings B. Zhang S. Zane A. Breeveld D. N. Burrows N. Gehrels C. Gronwall S. Hunsberger C. Markwardt K. O. Mason P. Mészáros J. P. Norris † S. R. Oates C. Pagani T. S. Poole P. W. A. Roming P. J. Smith D. E. Vanden Berk 《Monthly notices of the Royal Astronomical Society》2007,380(3):1041-1052
78.
Riparian vegetation influences hydraulic and morphodynamic river processes and may contribute to sediment stabilization. In turn, vegetation recruitment and growth on non‐cohesive fluvial deposits strongly depends on river hydrology and the ability of roots to develop and to anchor efficiently to resist flow erosion. In this paper, we examine the above‐ground and the below‐ground seasonal growth dynamics of Salix cuttings in relation to local river hydrodynamics and morphodynamics, on the basis of a detailed and unique data set. During the two season‐long campaigns in 2009 and 2010, 1188 and 1152 cuttings, respectively, were organized in square plots and planted on a gravel island of the restored reach of the River Thur (Neunforn, Thurgau, Switzerland). Each year, all cuttings were monitored almost regularly from the beginning until the end of the growing season (April–September). Root development statistics were also obtained from high‐resolution scanner analysis of carefully uprooted samples from selected plots. Our results show how cutting survival and the nature and strength of correlations between island topography and cutting growth statistics depend on river hydrology. An empirical functional form that links root development based on the measured main stem length is then proposed for predictive purposes. Cutting mortality following flood events is shown to depend nonlinearly on both erosion and deposition processes, whereas it appears more linearly related to the magnitude of the bed shear stress distribution generated by the maximum seasonal flood. This analysis allows an identification of an important threshold for plant survival within different erosion and deposition regimes, which explains the spatial and temporal distribution of the surviving cuttings within the plots. These results have practical implications, for instance, for evaluating, planning and managing the use of riparian trees in restoration projects. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
79.
Pasquale Crea Concetta De Stefano Frank J. Millero Silvio Sammartano Virender K. Sharma 《Aquatic Geochemistry》2010,16(3):447-466
Oxidized glutathione (GSSG), which has four carboxylic and two amino groups, interacts with metal ions and may affect the
bioavailability and geochemistry of metals in natural waters. In the present paper, six stepwise protonation constants
K\textHi K^{\text{H}}_{i} for GSSG were measured as a function of salinity, S = 5–35‰ at t = 25°C (and in NaCl/MgCl2 mixtures at different ionic strengths), in order to provide thermodynamic data for their acid base properties, which are
useful for studying the interaction with metals in these media. The protonation enthalpies (ΔH
i
/kJ mol−1) were also determined at t = 25°C. The results were interpreted using the SIT model and Pitzer equations. The seawater model with the interaction parameters
accounts for the differences between the values in NaCl and seawater. The results suggest that it is important to consider
all of the ionic interactions in natural waters in examining the proton dissociation of GSSG. 相似文献
80.
One century ago Viktor Hess carried out several balloon flights that led him to conclude that the penetrating radiation responsible for the discharge of electroscopes was of extraterrestrial origin. One century from the discovery of this phenomenon seems to be a good time to stop and think about what we have understood about Cosmic Rays. The aim of this review is to illustrate the ideas that have been and are being explored in order to account for the observable quantities related to cosmic rays and to summarize the numerous new pieces of observation that are becoming available. In fact, despite the possible impression that development in this field is somewhat slow, the rate of new discoveries in the last decade or so has been impressive, and mainly driven by beautiful pieces of observation. At the same time scientists in this field have been able to propose new, fascinating ways to investigate particle acceleration inside the sources, making use of multifrequency observations that range from the radio, to the optical, to X-rays and gamma rays. These ideas can now be confronted with data.I will mostly focus on supernova remnants as the most plausible sources of Galactic cosmic rays, and I will review the main aspects of the modern theory of diffusive particle acceleration at supernova remnant shocks, with special attention for the dynamical reaction of accelerated particles on the shock and the phenomenon of magnetic field amplification at the shock. Cosmic-ray escape from the sources is discussed as a necessary step to determine the spectrum of cosmic rays at the Earth. The discussion of these theoretical ideas will always proceed parallel to an account of the data being collected especially in X-ray and gamma-ray astronomy.In the end of this review I will also discuss the phenomenon of cosmic-ray acceleration at shocks propagating in partially ionized media and the implications of this phenomenon in terms of width of the Balmer line emission. This field of research has recently experienced a remarkable growth, in that Hα lines have been found to bear information on the cosmic-ray acceleration efficiency of supernova shocks. 相似文献