Climate variability and Alpine glaciers evolution in Northwestern Italy from the Little Ice Age to the 2010s     

Guido Nigrelli  Stefania Lucchesi  Stefania Bertotto  Gianfranco Fioraso  Marta Chiarle 《Theoretical and Applied Climatology》2015,122(3-4):595-608

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An operational model to estimate hourly and daily crop evapotranspiration in hilly terrain: validation on wheat and oat crops   总被引：2，自引：1，他引：1  

Gianfranco Rana  Nader Katerji  Rossana M. Ferrara  Nicola Martinelli 《Theoretical and Applied Climatology》2011,103(3-4):413-426

In this paper, we present an operational model to estimate the actual evapotranspiration (ET) of crops cultivated on hilly terrains. This new model has the following three characteristics: (1) ET modelling is based on a Penman?CMonteith (PM) type equation (Monteith 1965) where canopy resistance is simulated by following an approach already illustrated by Katerji and Perrier (Agronomie 3(6):513?C521, 1983); (2) the estimation of ET, by means of the PM equation, is made by using meteorological variables simulated on sloped sites as input; (3) these variables are simulated by using simple relationships linking the variables measured at a reference site on plane to the topographic characteristics of the site (slope, orientation, altitude as difference between reference, and sloped sites). This approach presents two advantages if compared with previously proposed models: Not only computation steps are greatly simplified but also error sources due to the simulation of climatic variables in sloped sites and the ET estimation are well distinguished. This model was validated at hourly and daily scales at four sites cultivated with wheat and oats offering a wide range of slope and orientation values: a reference site on plane, site 1 (9° sloping, NW orientation, 7 m from the reference site in plane), site 2 (6°, SE, 12 m) and site 3 (1°, SE, 18 m). At hourly scale, the new model performed well at all sites studied. The observed slope of the linear relationships between estimated and measured ET values ranged between 0.93 and 1.03, with coefficients of determination, r ², between 0.80 and 0.98. At daily scale, the slopes of the linear relationships between measured and estimated ET for the sites on plane and the sloped sites were practically the same (0.98?±?0.01); however, the coefficient of determination r ² observed in the site on plane was clearly greater (0.98) than that observed in the sloped sites (0.83). The presented analysis does not show any significant systematic effect of topography (slope and orientation of the plots) on the good performance of the proposed model for the ET estimation. Furthermore, we observed that coefficients of determination tend to decrease with the increase in the slope of the site, which translates into increased inaccuracy of the climatic variables simulation, in particular the net radiation, as the slope of the site increases. The proposed model allows to verify the different steps for calculating the fluxes, to identify the eventual sources of error and to make the needed corrections. For this reasons, the proposed model seems to be particularly ??operational??, i.e. a useful tool for estimating fluxes on hilly terrains.  相似文献   

Analysis of the liquefaction phenomena in the village of Vittorito (L��Aquila)     

Paola Monaco  Filippo Santucci de Magistris  Salvatore Grasso  Silvano Marchetti  Michele Maugeri  Gianfranco Totani 《Bulletin of Earthquake Engineering》2011,9(1):231-261

This paper describes a case-history of liquefaction occurred near the village of Vittorito after the April 6, 2009 L’Aquila earthquake (moment magnitude M_w = 6.3), approximately 45 km far from the epicentre. In the document, first, an estimation of the seismic motion in the area has been made. Thereafter, the performed geotechnical investigation is described, followed by the application of some fast assessment criteria for the occurrence of liquefaction, recently proposed by the new Italian Building Code. A careful assessment of all the parameters involved in conventional Seed and Idriss (1971) liquefaction analyses is considered. The cyclic resistance ratio CRR is evaluated by cone penetration tests CPT and by in situ seismic dilatometer tests SMDT; in the latter case CRR is evaluated by different empirical correlations with shear wave velocity V_s and horizontal stress index K_D. Analytical data confirmed the observed occurrence of the liquefaction in Vittorito, even if the acceleration field in the area, produced by the L’Aquila earthquake, was very low.  相似文献   

The properties of extragalactic radio sources selected at 20 GHz     

Elaine M. Sadler  Roberto Ricci  Ronald D. Ekers  J. A. Ekers  Paul J. Hancock  Carole A. Jackson  Michael J. Kesteven  Tara Murphy  Chris Phillips  Robert F. Reinfrank  Lister Staveley-Smith  Ravi Subrahmanyan  Mark A. Walker  Warwick E. Wilson  Gianfranco De Zotti 《Monthly notices of the Royal Astronomical Society》2006,371(2):898-914

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Annihilation radiation from a dark matter spike at the Galactic Centre     

Gianfranco Bertone  Günter Sigl  Joseph Silk 《Monthly notices of the Royal Astronomical Society》2002,337(1):98-102

We study annihilation radiation of neutralinos in the Galactic Centre, assuming the existence of a 'spike' in the dark matter density profile, caused by adiabatic accretion on to the massive black hole lying at the Galactic Centre. Under this assumption we find that it is possible to reproduce the observed SgrA* emission at radio and gamma-ray frequencies in a consistent scenario with a magnetic field close to the equipartition strength and with values of γ (the density profile power-law index) around 0.1.  相似文献   

Vestan lithologies mapped by the visual and infrared spectrometer on Dawn     

Eleonora Ammannito  M. Cristina De Sanctis  Fabrizio Capaccioni  M. Teresa Capria  F. Carraro  Jean‐Philippe Combe  Sergio Fonte  Alessandro Frigeri  Steven P. Joy  Andrea Longobardo  Gianfranco Magni  Simone Marchi  Thomas B. McCord  Lucy A. McFadden  Harry Y. McSween  Ernesto Palomba  Carle M. Pieters  Carol A. Polanskey  Carol A. Raymond  Jessica M. Sunshine  Federico Tosi  Francesca Zambon  Christopher T. Russell 《Meteoritics & planetary science》2013,48(11):2185-2198

We present global lithological maps of the Vestan surface based on Dawn mission's Visible InfraRed (VIR) Spectrometer acquisitions with a spatial sampling of 200 m. The maps confirm the results obtained with the data set acquired by VIR with a spatial sampling of 700 m, that the reflectance spectra of Vesta's surface are dominated by pyroxene absorptions that can be interpreted within the context of the distribution of howardites, eucrites, and diogenites (HEDs). The maps also partially agree with the ground and Hubble Space Telescope observations: they confirm the background surface being an assemblage of howardite or polymict eucrite, as well as the location of a diogenitic‐rich spot; however, there is no evidence of extended olivine‐rich regions in the equatorial latitudes. Diogenite is revealed on the Rheasilvia basin floor, indicating that material of the lower crust/mantle was exposed. VIR also detected diogenites along the scarp of Matronalia Rupes, and the rims of Severina and a nearby, unnamed crater, and as ejecta of Antonia crater. The diogenite distribution is fully consistent with petrological constraints; although the mapped distribution does not provide unambiguous constraints, it favors the hypothesis of a magma ocean.  相似文献   

First results from the Australia Telescope Compact Array 18-GHz pilot survey     

Roberto Ricci  Elaine M. Sadler  Ronald D. Ekers  Lister Staveley–Smith  Warwick E. Wilson  Michael J. Kesteven  Ravi Subrahmanyan  Mark A. Walker  Carole A. Jackson  Gianfranco De Zotti 《Monthly notices of the Royal Astronomical Society》2004,354(1):305-320

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Limitations of an Eddy-Covariance System in Measuring Low Ammonia Fluxes     

Ferrara  Rossana Monica  Di Tommasi  Paul  Famulari  Daniela  Rana  Gianfranco 《Boundary-Layer Meteorology》2021,180(1):173-186

Green manuring of legume crops can improve soil fertility and sustainability. To evaluate its agronomic and environmental effectiveness, gaseous losses of ammonia (NH₃) in the surface layer need to be quantified by direct measurements in the field. However, the application of the eddy-covariance technique to atmospheric NH₃ is challenging: its high reactivity, water solubility, and low background concentrations all hinder the response time of closed-path sensors for fast measurements of NH₃ concentration. Ammonia emissions following green manuring were measured for 21 days using a flux system equipped with a fast-pulsed quantum-cascade tunable-infrared-laser spectrometer. The noisy cross-covariance function for this configuration indicates flux measurements are close to the limit of detection; the low signal-to-noise ratio further increases the uncertainties, introducing a mirroring effect on the fluxes, which results in the rapid alternation between emission and deposition, within the limit of detection (around 13 and 20 ng m^?2 s^?1, at the 95 and 99% confidence limits, respectively). An evaluation of the measurement errors is presented, focussing on three technical aspects of the eddy-covariance system: (1) time lag, (2) random error, and (3) limit of detection. The NH₃ fluxes measured by the spectrometer are close to its limit of detection, with a random error of the same order as the flux.

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Antioxidant responses to variations in dissolved oxygen of Scapharca inaequivalvis and Tapes philippinarum, two bivalve species from the lagoon of Venice     

Irato P  Piccinni E  Cassini A  Santovito G 《Marine pollution bulletin》2007,54(7):1020-1030

The aim of the present work was to determine the activities of selected antioxidant enzymes (SOD, Se-GPX, CAT) in two species of bivalves, Scapharca inaequivalvis and Tapes philippinarum, from two sites of the lagoon of Venice that are characterized by different pO(2) (Marghera and Chioggia). The specimens were collected at four times during a 1-year period. In the two species studied, enzyme activities were found to be present in both digestive glands and gills, but with some species-specific differences that may also represent a different adaptation to seasonal variations. The presence of high SOD activities in the gills of both species may be related to their physiological role in respiration. Scapharca inaequivalvis is less sensitive than T. philippinarum to environmental changes, perhaps due to the presence of hemoglobins in this species. Moreover, in the digestive gland of T. philippinarum we found a significant negative correlation between the activities of SOD and GPX that may indicate the presence of oxidative stress. Some correlations between temperature/dissolved oxygen and antioxidant enzyme activity were present in specimens sampled in Marghera. Only GPX adequately responded to changes in dissolved oxygen and temperature, while the decrease in the activity of SOD and CAT in winter may be directly responsible for an enhanced susceptibility of mussels to oxidative stress during this period. We can conclude that the observed differences between Chioggia and Marghera are due to different concentrations of dissolved oxygen. Marghera is an appropriate location to study seasonal variations in water temperature. In fact, in this site, the differences between hot and cold months are quite evident.  相似文献   

A simple numerical procedure for timely prediction of precipitation-induced landslides in unsaturated pyroclastic soils   总被引：4，自引：4，他引：0  

Luca Pagano  Luciano Picarelli  Guido Rianna  Gianfranco Urciuoli 《Landslides》2010,7(3):273-289

In the last 20 years, several catastrophic precipitation-induced landslides have hit villages, towns and roads in Campania (southern Italy), causing extensive damage and many fatalities. Although such phenomena have occurred since time immemorial, recent urbanisation and infrastructural development have produced a major increase in landslide risk. Due to climatic changes and further unavoidable increases in exposure, in the near future, the risk will become even greater. It is therefore high time to develop reliable criteria for landslide prediction. The paper discusses the main factors which affect the triggering of precipitation-induced landslides, highlighting the key role played by antecedent rainfalls which cannot be precisely accounted for using empirical criteria. We propose a simple 1D numerical approach able to predict the evolution of the key factors governing slope stability as a tool to predict the onset of slope failure, with potential benefits for early warning systems. The approach is calibrated through a well-documented case history.  相似文献