Assessment of Planetary-Boundary-Layer Schemes in the Weather Research and Forecasting Model Within and Above an Urban Canopy Layer     

Enrico Ferrero  Stefano Alessandrini  Francois Vandenberghe 《Boundary-Layer Meteorology》2018,168(2):289-319

We tested several planetary-boundary-layer (PBL) schemes available in the Weather Research and Forecasting (WRF) model against measured wind speed and direction, temperature and turbulent kinetic energy (TKE) at three levels (5, 9, 25 m). The Urban Turbulence Project dataset, gathered from the outskirts of Turin, Italy and used for the comparison, provides measurements made by sonic anemometers for more than 1 year. In contrast to other similar studies, which have mainly focused on short-time periods, we considered 2 months of measurements (January and July) representing both the seasonal and the daily variabilities. To understand how the WRF-model PBL schemes perform in an urban environment, often characterized by low wind-speed conditions, we first compared six PBL schemes against observations taken by the highest anemometer located in the inertial sub-layer. The availability of the TKE measurements allows us to directly evaluate the performances of the model; results of the model evaluation are presented in terms of quantile versus quantile plots and statistical indices. Secondly, we considered WRF-model PBL schemes that can be coupled to the urban-surface exchange parametrizations and compared the simulation results with measurements from the two lower anemometers located inside the canopy layer. We find that the PBL schemes accounting for TKE are more accurate and the model representation of the roughness sub-layer improves when the urban model is coupled to each PBL scheme.  相似文献   

Quantifying Particle Numbers and Mass Flux in Drifting Snow     

Philip Crivelli  Enrico Paterna  Stefan Horender  Michael Lehning 《Boundary-Layer Meteorology》2016,161(3):519-542

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2D numerical simulations of earthquake ground motion: examples from the Marche Region,Italy     

Giovanna Laurenzano  Enrico Priolo  Emanuele Tondi 《Journal of Seismology》2008,12(3):395-412

A detailed numerical simulation of the ground motion and a site response analysis for two towns in the Marche Region (Treia and Cagli) is carried out on the basis of structural models deduced from available geological and geophysical data. In both cases, the reference event is an M = 5.7 earthquake associated with a normal fault located beneath each town. The ground motion is computed using the 2D spectral element method (SPEM 2D). The method solves the propagation of the seismic field through complex geological structures and enables an estimate of the effects of deep crustal structure, superficial geology, and topography on ground motion. Numerical simulations of the seismic field are performed along 2D vertical planes containing the seismic source. Strong ground motion has not been yet recorded in the two towns; therefore, the numerical simulation of ground motion represents a way to overcome the lack of instrumental data. The simulations carried out for Treia show that ground motion is influenced by both source mechanism and effects due to propagation through the geological structure, while ground motion in Cagli features strong local effects, caused by the presence of alluvial deposits under a large area of the town.  相似文献   

Preface     

Monica Pondrelli  Ken Tanaka  Angelo Pio Rossi  Enrico Flamini 《Planetary and Space Science》2011,59(11-12):1113

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A multidisciplinary approach to reveal the Sicily Climate and Environment over the last 20 000 years     

Alessandro Incarbona  Giuseppe Zarcone  Mauro Agate  Sergio Bonomo  Enrico Di Stefano  Federico Masini  Fabio Russo  Luca Sineo 《Central European Journal of Geosciences》2010,2(2):71-82

We present a thorough review of the knowledge on the climate and environment in Sicily over the last 20 000 years, taking into account results of several studies carried using terrestrial and marine records. We obtain a coherent framework of the most important changes succeeded in the island, even if some points need further investigation. All the reconstructions of surface temperatures of the seas and the air surrounding Sicily point out severe climatic conditions during the last glacial period. The steppe- and semisteppe-like vegetation pattern testifies, together with additional evidence from geochemical data of lacustrine evidence, markedly arid conditions. Fi-nally, significant episodes of sea level drop connected Sicily to the Italian Peninsula and favoured the dispersion of faunal elements from southern Italy. The transition between the last glacial and the Holocene was not characterized by a gradual warming but was punctuated by two abrupt suborbital climatic fluctuations: Bølling-Allerød (warm) and Younger Dryas (cold), as recognized in the sediments recovered close to the northern and southern coast of Sicily. A denser arboreal cover is possibly indicated by the occurrence of dormouse and Arvicola remains. Finally the sensitivity of Sicily to climate perturbations is demonstrated by the occurrence of repeated subtle climatic anomalies during the Holocene, including the Little Ice Age, also known from historical chronicles. Forests, woods and Mediterranean maquis developed in the early-middle Holocene. Thereafter was a general decline of arboreal vegetation, following a general aridification trend that seems to be a common feature in southern Europe and North Africa. Science Greek colonization (7^th century before Christ), the landscape was intensively modelled for agriculture and breeding, leading to a significant loss of vegetation cover.  相似文献   

A visco‐damage model for brittle materials under monotonic and sustained stresses     

Enrico Papa  Alberto Taliercio 《国际地质力学数值与分析法杂志》2005,29(3):287-310

A theoretical model is proposed to describe the evolution of damage in brittle materials, such as concrete and masonry, subjected to increasing or sustained stresses of relatively high intensity. The model is based on the introduction of suitable damage variables in a rheological model. In this way, it is possible to describe the material behaviour under stresses either increasing or constant in time. The capabilities of the model in describing the mechanical response of material elements subjected to different stress histories are illustrated. Some correlations with experimental data from tests performed on masonry and concrete specimens are presented, to assess the reliability of the theoretical predictions. The results of some numerical applications to non‐proportional stress paths are also illustrated. Finally, the limitations of the proposal are discussed and possible further improvements are envisaged. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

The effects of post-orogenic extension on different scales: an example from the Apennine–Maghrebide fold-and-thrust belt, SW Sicily     

Enrico Tavarnelli  Pietro Renda  Valeria Pasqui  Mariano Tramutoli 《地学学报》2003,15(1):1-7

ABSTRACT Many structures produced under one single deformation regime, namely extensional, contractional or strike-slip, exhibit remarkable geometrical analogies when analysed at different scales. By contrast, field examples that illustrate the scale effects on structures resulting from superimposed deformations, which were produced under different tectonic regimes, are rare. Yet the change from contraction to extension is known to occur often in the most thickened portions of the continental crust. The Apennine–Maghrebide fold-and-thrust belt of Sicily shows many examples of post-orogenic extensional deformations. Composite structures, resulting from late normal faults that offset folds and thrusts, are observed at four different scales, from regional to mesoscopic, in the south-western portion of Sicily and in the adjacent Isle of Favignana. The recognized analogies in the geometry of these composite structures may provide a key for the interpretation of the features of regional structures, whose deep geometry is often poorly constrained. Moreover, comparison of normalized displacements accommodated by contractional and extensional faults of different scales indicates that self-similarity is not unique to structures produced under single tectonic regimes.  相似文献   

Events in the life of a cocoon surrounding a light, collapsar jet     

Enrico Ramirez-Ruiz  Annalisa Celotti  Martin J. Rees 《Monthly notices of the Royal Astronomical Society》2002,337(4):1349-1356

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Application of a Bivariate Gamma Distribution for a Chemically Reacting Plume in the Atmosphere     

Enrico Ferrero  Luca Mortarini  Stefano Alessandrini  Carlo Lacagnina 《Boundary-Layer Meteorology》2013,147(1):123-137

The joint concentration probability density function of two reactive chemical species is modelled using a bivariate Gamma distribution coupled with a three-dimensional fluctuating plume model able to simulate the diffusion and mixing of turbulent plumes. A wind-tunnel experiment (Brown and Bilger, J Fluid Mech 312:373–407, 1996), carried out in homogeneous unbounded turbulence, in which nitrogen oxide is released from a point source in an ozone doped background and the chemical reactions take place in non-equilibrium conditions, is considered as a test case. The model is based on a stochastic Langevin equation reproducing the barycentre position distribution through a proper low-pass filter for the turbulence length scales. While the meandering large-scale motion of the plume is directly simulated, the internal mixing relative to the centroid is reproduced using a bivariate Gamma density function. The effect of turbulence on the chemical reaction (segregation), which in this case has not yet attained equilibrium, is directly evaluated through the covariance of the tracer concentration fields. The computed mean concentrations and the O₃–NO concentration covariance are also compared with those obtained by the Alessandrini and Ferrero Lagrangian single particle model (Alessandrini and Ferrero, Physica A 388:1375–1387, 2009) that entails an ad hoc parametrization for the segregation coefficient.  相似文献   

A multiwavelength map of the nuclear region of NGC 7582     

Stefano Bianchi  Marco Chiaberge  Enrico Piconcelli  Matteo Guainazzi 《Monthly notices of the Royal Astronomical Society》2007,374(2):697-702

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