Predicting new snow density in the Italian Alps: A variability analysis based on 10 years of measurements          下载免费PDF全文

Mauro Valt  Nicolas Guyennon  Franco Salerno  Anna B. Petrangeli  Rosamaria Salvatori  Paola Cianfarra  Emanuele Romano 《水文研究》2018,32(20):3174-3187

Despite its strong impact on the time evolution of the snowpack, current estimation of new snow density (ρ_hn) is usually accomplished either by using local empirical techniques or by assuming a constant snow density. Faced with the lack of an estimation model of ρ_hn valid for a wide spatial scale and supported by a suitable number of observations, this study aims to develop simple monthly linear regression models at scale of the entire Italian Alpine chain based on 12,112 snowfall observations at 122 stations, using only air temperature as predictor. Moreover, the remaining variance is investigated in both time and space, also considering some qualitative features of the snowfall events. The daily ρ_hn measurements present a mean value of 115 kg m^?3 (105 and 159 kg m^?3 for dry and wet conditions, respectively). The mean air temperature of the 24 hr preceding the snowfall event has been found to be the best predictor of the ρ_hn, within 31% of uncertainty. The analysis of associated residues allows supporting the idea that the adoption of a more local approach than the one analysed here is not able to substantially increase the predictive capabilities of the model. In fact, the main factor explaining the remaining variance over the air temperature is the wind, but in a complex orography, as mountain regions are, supplying realistic local wind fields is particularly challenging. Therefore, we conclude that using only the daily mean temperature as predictor is a good choice for estimating daily new snow density at scale of Italian Alpine chain, as well as at more regional scale.  相似文献   

New geomorphological and chronological constraints for glacial deposits in the Rivoli‐Avigliana end‐moraine system and the lower Susa Valley (Western Alps,NW Italy)          下载免费PDF全文

Susan Ivy‐Ochs  Stefania Lucchesi  Paolo Baggio  Gianfranco Fioraso  Franco Gianotti  Giovanni Monegato  Angela A. Graf  Naki Akçar  Marcus Christl  Francesco Carraro  Maria Gabriella Forno  Christian Schlüchter 《第四纪科学杂志》2018,33(5):550-562

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Strömgren 4-Color Photometry of Very Metal-Poor Stars     

W.J. Schuster  L. Parrao  A. Franco  T.C. Beers  P.E. Nissen 《Astrophysics and Space Science》1999,265(1-4):183-184

Strömgren uvby photometry has been observed for an additional 140 very metal-poor stars from the survey of Beers et al. (1992). These Galactic stars of very-low metallicity provide crucial information for the investigation of the formation and evolution of the Galaxy, as well as on the nature of the early Universe. The Strömgren uvby-β system allows the measurement of stellar atmospheric parameters as a prelude to detailed abundance studies which will make use of high-resolution spectroscopy and the new generation of large telescopes. The photometric techniques developed by Schuster et al. (1996) are used not only to classify these very metal-poor stars but also to derive effective temperatures, surface gravities, and improved estimates for their interstellar reddenings. In particular, photometric diagrams such as [c ₁], [m ₁] and c ₀, (b-y)₀ are used to classify these stars, especially those near the main-sequence turnoff, where contamination from slightly-evolved subgiants, lower surface-gravity horizontal-branch stars, and even a few supergiant or AGB candidates is found.  相似文献   

New Insights on Mt. Etna’s Crust and Relationship with the Regional Tectonic Framework from Joint Active and Passive P-Wave Seismic Tomography     

A. Díaz-Moreno  G. Barberi  O. Cocina  I. Koulakov  L. Scarfì  L. Zuccarello  J. Prudencio  A. García-Yeguas  I. Álvarez  L. García  J. M. Ibáñez 《Surveys in Geophysics》2018,39(1):57-97

In the Central Mediterranean region, the production of chemically diverse volcanic products (e.g., those from Mt. Etna and the Aeolian Islands archipelago) testifies to the complexity of the tectonic and geodynamic setting. Despite the large number of studies that have focused on this area, the relationships among volcanism, tectonics, magma ascent, and geodynamic processes remain poorly understood. We present a tomographic inversion of P-wave velocity using active and passive sources. Seismic signals were recorded using both temporary on-land and ocean bottom seismometers and data from a permanent local seismic network consisting of 267 seismic stations. Active seismic signals were generated using air gun shots mounted on the Spanish Oceanographic Vessel ‘Sarmiento de Gamboa’. Passive seismic sources were obtained from 452 local earthquakes recorded over a 4-month period. In total, 184,797 active P-phase and 11,802 passive P-phase first arrivals were inverted to provide three different velocity models. Our results include the first crustal seismic active tomography for the northern Sicily area, including the Peloritan–southern Calabria region and both the Mt. Etna and Aeolian volcanic environments. The tomographic images provide a detailed and complete regional seismotectonic framework and highlight a spatially heterogeneous tectonic regime, which is consistent with and extends the findings of previous models. One of our most significant results was a tomographic map extending to 14 km depth showing a discontinuity striking roughly NW–SE, extending from the Gulf of Patti to the Ionian Sea, south-east of Capo Taormina, corresponding to the Aeolian–Tindari–Letojanni fault system, a regional deformation belt. Moreover, for the first time, we observed a high-velocity anomaly located in the south-eastern sector of the Mt. Etna region, offshore of the Timpe area, which is compatible with the plumbing system of an ancient shield volcano located offshore of Mt. Etna.  相似文献   

Multiscale Analysis of the Instantaneous Eccentricity Oscillations of the Planets of the Solar System from 13 000 BC to 17 000 AD     

Scafetta  Nicola  Milani  Franco  Bianchini  Antonio 《Astronomy Letters》2019,45(11):778-790

Astronomy Letters - The high-resolution Jet Propulsion Laboratory DE431 and DE432 planetary ephemeris are used to evaluate the instantaneous eccentricity functions of the orbits of the planets of...  相似文献   

Overtopping performance of different armour units for rubble mound breakwaters     

T. Bruce  J.W. van der Meer  L. Franco  J.M. Pearson 《Coastal Engineering》2009

This paper describes a major programme of small-scale physical model tests to establish better the influence of armour type and configuration on overtopping. Specifically, 179 tests determined the relative difference in overtopping behaviour for 13 types/configurations of armour. Roughness factors γ_f were determined for rock (two layers), cubes (single layer and two layers), Tetrapod, Antifer, Haro, Accropode, Core-Loc™ and Xbloc™. These roughness influence factors have been included in the CLASH database and are for use in the neural network prediction of overtopping. Individual wave-by-wave overtopping volumes were analysed and found to compare well with current prediction methods. Measured reflection coefficients for the different units are also presented and compared with recent formulae.  相似文献   

Natural hazard risk in the case of an emergency: the real options’ approach     

Ludovic Gaudard  Franco Romerio 《Natural Hazards》2015,75(1):473-488

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Measurement of long waves at the harbor of Marina di Carrara,Italy   总被引：2，自引：2，他引：0  

Giorgio Bellotti  Leopoldo Franco 《Ocean Dynamics》2011,61(12):2051-2059

This paper presents the analysis of measurements of long waves at the harbor of Marina di Carrara, Italy. Nine pressure gauges (eight in the inner harbor and one outside the harbor) were used to record continuously the water surface elevation, for about 3 years; incoming short waves were measured using a directional buoy at about 500 m offshore the breakwaters. The analysis is carried out splitting the energy of the long waves into two bands, i.e., very long waves (VLW; f < 0.003 Hz) and long waves (LW; 0.003 < f < 0.030 Hz); it is found that LW energy is strongly correlated with the energy of the incoming short waves while no correlation (or very poor) is found for VLW. During energetic sea states, surface elevation spectra of VLW and LW, normalized against the wave energy of each frequency band, appear to be autosimilar; this suggests that the spectra of the incoming long waves have a mostly constant shape. Simple numerical computations of harbor resonance, carried out using a mild-slope equation linearized model, indicate that the amplification of the height of the incoming LW generated by short waves (calculated using empirical formulae from previous researches by Melito et al. 2007) inside the harbor can be reasonably predicted using such simple approach, assuming that the LW spectra are rectangular. The shape of the amplification diagram calculated by the numerical model shows reasonable (but not perfect) agreement with the shape of the normalized measured spectra inside the harbor.  相似文献   

Re–Os and <Superscript>40</Superscript>Ar/<Superscript>39</Superscript>Ar ages of the Jiguanshan porphyry Mo deposit,Xilamulun metallogenic belt,NE China,and constraints on mineralization events     

Huaying Wu  Lianchang Zhang  Bo Wan  Zhiguang Chen  Peng Xiang  Franco Pirajno  Andao Du  Wenjun Qu 《Mineralium Deposita》2011,46(2):171-185

The large Jiguanshan porphyry Mo deposit, with more than 100 Mt of ore and grades ranging from 0.08% to 0.11%, is located in the newly identified Xilamulun metallogenic belt along the northern margin of the North China Craton. The Mo mineralization is predominantly disseminated in the host granite porphyry, but locally occurs as stockworks in lithic tuff and rhyolitic rocks. ⁴⁰Ar/³⁹Ar dates of samples from groundmass material in the host granite porphyry, post-ore diabase, and quartz porphyry dikes show plateau ages of 155.1 ± 1.9, 149.4 ± 0.9, and 147.6 ± 0.9 Ma, with inverse isochron ages of 156.0 ± 1.8, 149.3 ± 1.3, and 148.3 ± 1.2 Ma, respectively. Seven samples of disseminated molybdenite yielded a weighted average ¹⁸⁷Re-¹⁸⁷Os age of 155.3 ± 0.9 Ma, whereas six veinlet-type molybdenite samples yielded a weighted average ¹⁸⁷Re-¹⁸⁷Os age of 153.0 ± 0.9 Ma, providing direct timing constraints for the Mo mineralization at 153–155 Ma. The regional geological setting together with the emplacement of post-ore diabase and quartz porphyry dikes in the Jiguanshan deposit, are indicative of an extensional regime in Late Jurassic, which was probably linked to lithospheric extension in northeast China.  相似文献   

Phytoplankton pigments and epifluorescence microscopy as tools for ecological status assessment in coastal and estuarine waters, within the Water Framework Directive   总被引：1，自引：0，他引：1  

Seoane S  Garmendia M  Revilla M  Borja A  Franco J  Orive E  Valencia V 《Marine pollution bulletin》2011,62(7):1484-1497

Inverted microscopy is widespread employed for the analysis of phytoplankton composition within water quality monitoring networks. However, the analysis at the lowest taxonomical level is not always required for ecological status assessment. In addition, inverted microscopy can underestimate the small phytoplankton, and not always distinguish photoautotrophic from heterotrophic cells. In this study, as alternative tools, epifluorescence microscopy and High Performance Liquid Chromatography (HPLC) were employed to characterize phytoplankton communities within waters of different trophic condition. Epifluorescence microscopy confirmed its effectiveness to count the small phytoplankton. Furthermore, significant correlations between nutrients of anthropogenic origin and nanoplankton abundances were found. However, this technique resulted very time-consuming. HPLC together with the CHEMTAX program was more appropriate than inverted microscopy, in terms of cost-effectiveness. Also, the main variability patterns observed in the phytoplankton community structure by HPLC coincided with previous findings in the study area. Nevertheless, a rapid screening at the inverted microscope is recommended.  相似文献