Influence of the Sonic Anemometer Temperature Calibration on Turbulent Heat-Flux Measurements     

Renzo Richiardone  Massimiliano Manfrin  Silvia Ferrarese  Caterina Francone  Vito Fernicola  Roberto Maria Gavioso  Luca Mortarini 《Boundary-Layer Meteorology》2012,142(3):425-442

The speed of sound in moist air is discussed and a more accurate value for the coefficient of the linear dependence of sonic temperature on specific humidity is proposed. An analysis of speed-of-sound data measured by three sonic anemometers in a climate chamber and in the field shows that the temperature response of each instrument significantly influences not only the determination of sonic temperature, but also its fluctuations. The corresponding relative contribution to the error in the evaluation of the temperature fluctuations and the turbulent heat fluxes can be as high as 40%. The calibration procedure is discussed and a method of correction is proposed.  相似文献   

Production and processing of silicates in laboratory and in space     

John R Brucato  Vito Mennella 《Planetary and Space Science》2002,50(9):829-837

Since their formation in the outflows of evolved stars, materials suffer in space deep chemical and physical modifications. Most abundant elements (C, N, O, Mg, Si, S and Fe) are present in dust as refractory chemical species. Among them silicates are one of the main constituents. Spectroscopic observations in various astronomical environments have shown that magnesium rich silicates are present both in amorphous and in crystalline form. An accurate interpretation of these observations requires studies on the formation of silicate dust in the atmospheres of giant stars and their evolution in the interstellar medium until their inclusion in protoplanetary disks.Many theoretical works have described the chemical and physical evolution of solids in space and their link to observable optical properties. Laboratory studies of cosmic dust analogues are needed to investigate these processes experimentally.In this work, experiments aimed at simulating the formation of silicates in space are presented. In particular, the laser ablation technique is used to produce amorphous silicates with various Si-Mg-Fe content. The analysis of their thermal evolution is presented.  相似文献   

1/f Fluctuations in geoelectrical signals observed in a seismic area of Southern Italy     

Marianna Balasco  Vincenzo Lapenna  Luciano Telesca   《Tectonophysics》2002,347(4)

Recent studies have shown that many natural systems display temporal fluctuations with long-range power-law correlations, suggesting a fractal geometry of the underlying dynamical system. Four geoelectrical time series, measured in a seismic area of Southern Italy, are investigated by means of spectral tools in order to evidence the existence of power-law correlations. Results show the scaling behaviour for all the signals recorded, pointing to the presence of fractal features expressing a long-term correlation with scaling exponents which indicate stabilizing mechanisms. Furthermore, our findings suggest an observational evidence of correlations between the variation of parameters describing the temporal fluctuations of geoelectrical signals and earthquakes that occurred in the area investigated.  相似文献   

On the methods to identify clustering properties in sequences of seismic time-occurrences     

L. Telesca  V. Cuomo  V. Lapenna  M. Macchiato 《Journal of Seismology》2002,6(1):125-134

In recent years there has been deep development in the use of techniquesto analyse the statistical properties of point process time series. Furthermoremany efforts have been made to establish robust methods to identify timeclustering structures in the temporal distribution of seismic events. In thispaper we intend to give a systematic review of some common usedtechniques to characterise the temporal properties of an earthquakesequence; we also present new methods, commonly used in other scientificfields, to reveal time clustering structures in a seismic sequence and toclearly identify non-poissonian behaviours at different time scales. Anapplication of these methods has been performed on the seismicity ofIrpinia-Basilicata area (Southern Italy).  相似文献   

Spectral measurements of aerosol particle extinction in the 0.4–3.7 μm wavelength range, performed at Sagres with the IR‐RAD sun‐radiometer     

Vito Vitale  Claudio Tomasi  Wolfgang Von Hoyningen&#;huene  Ubaldo Bonafe  Stefano Marani  Angelo Lupi  Alessandra Cacciari  Pietro Ruggeri 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):716-733

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The late Pleistocene pyroclastic deposits of the Campanian Plain: New insights into the explosive activity of Neapolitan volcanoes     

M.A. Di Vito  R. Sulpizio  G. Zanchetta  M. D'Orazio 《Journal of Volcanology and Geothermal Research》2008

The lithological and compositional characteristics of eighteen different pyroclastic deposits of Campanian origin, dated between 125 cal ky BP and 22 cal ky BP, were described. The pyroclastic deposits were correlated among different outcrops mainly located on the Apennine slopes that border the southern Campanian Plain. They were grouped in two main stratigraphic and chronologic intervals of regional significance: a) between Pomici di Base (22.03 cal ky BP; Somma–Vesuvius) and Campanian Ignimbrite (39 cal ky BP; Campi Flegrei) eruptions; and b) older than Campanian Ignimbrite eruption. Three new ¹⁴C AMS datings support the proposed correlations. Six eruptions were attributed to the Pomici di Base-Campanian Ignimbrite stratigraphic interval, while twelve eruptions are older than Campanian Ignimbrite. Of the studied deposits two originated from Ischia island, five are related to Campi Flegrei, and three to Somma–Vesuvius. Two eruptions have an uncertain correlation with Somma–Vesuvius or Campi Flegrei, while six eruptions remain of uncertain source. Minimum volumes of five eruptions were assessed, ranging between 0.5 km³ and 4 km³. Two of the studied deposits were correlated with Y-3 and X-5 tephra layers, which are widely dispersed in the central Mediterranean area. The new stratigraphic and chronologic data provide an upgraded chrono-stratigraphy for the explosive activity of Neapolitan volcanoes in the period between 125 and 22 cal ky BP.  相似文献   

Testing a new sampler for measuring plot soil loss          下载免费PDF全文

Francesco G. Carollo  Costanza Di Stefano  Vito Ferro  Vincenzo Pampalone  Francesco Sanzone 《地球表面变化过程与地形》2016,41(7):867-874

In order to measure soil loss in equipped plots the estimate of the weight of solid material intercepted at their lower end is required. At the experimental area of Sparacia, Sicily, the runoff produced by an erosive event is collected within storage tanks with a capacity of about 1 m³. In this paper, the use of a new sampler is proposed to measure easily the weight of solid material eroded from an experimental plot and collected into a storage tank. The sampler is a cylinder having a closing valve at the bottom. Two different series of runs were carried out both to test the reliability of the sampler and to establish a sampling procedure, respectively. An analysis of various sampling configurations usable in the field differentiated by the number and location of sampling verticals in the tank cross‐section was finally carried out. The results of the present investigation are that the concentration measurement by the sampler was more accurate than that obtained by other methods involving a collection tank, agitation and sampling of the suspension. This sampler is cheap and usable in combination with a quick field sampling procedure which is particularly advisable when the number of plots equipped at an experimental area is large. The sampler was tested using a clay soil contained within cylinders and a cubic tank, but it appeared also to be usable with coarser sediment than clay and in combination with tanks having a different shape. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

The Pomici di Avellino eruption of Somma-Vesuvius (3.9 ka bp). Part I: stratigraphy, compositional variability and eruptive dynamics     

R. Sulpizio  R. Cioni  M. A. Di Vito  D. Mele  R. Bonasia  P. Dellino 《Bulletin of Volcanology》2010,72(5):539-558

The stratigraphic succession of the Pomici di Avellino Plinian eruption from Somma-Vesuvius has been studied through field and laboratory data in order to reconstruct the eruption dynamics. This eruption is particularly important in the Somma-Vesuvius eruptive history because (1) its vent was offset with respect to the present day Vesuvius cone; (2) it was characterised by a distinct opening phase; (3) breccia-like very proximal fall deposits are preserved close to the vent and (4) the pyroclastic density currents generated during the final phreatomagmatic phase are among the most widespread and voluminous in the entire history of the volcano. The stratigraphic succession is, here, divided into deposits of three main eruptive phases (opening, magmatic Plinian and phreatomagmatic), which contain five eruption units. Short-lived sustained columns occurred twice during the opening phase (H_t of 13 and 21.5 km, respectively) and dispersed thin fall deposits and small pyroclastic density currents onto the volcano slopes. The magmatic Plinian phase produced the main volume of erupted deposits, emplacing white and grey fall deposits which were dispersed to the northeast. Peak column heights reached 23 and 31 km during the withdrawal of the white and the grey magmas, respectively. Only one small pyroclastic density current was emplaced during the main Plinian phase. In contrast, the final phreatomagmatic phase was characterised by extensive generation of pyroclastic density currents, with fallout deposits very subordinate and limited to the volcano slopes. Assessed bulk erupted volumes are 21 × 10⁶ m³ for the opening phase, 1.3–1.5 km³ for the main Plinian phase and about 1 km³ for the final phreatomagmatic phase, yielding a total volume of about 2.5 km³. Pumice fragments are porphyritic with sanidine and clinopyroxene as the main mineral phases but also contain peculiar mineral phases like scapolite, nepheline and garnet. Bulk composition varies from phonolite (white magma) to tephri-phonolite (grey magma).  相似文献   

Measuring multifractality in seismic sequences   总被引：6，自引：0，他引：6  

Luciano Telesca  Vincenzo Lapenna 《Tectonophysics》2006,423(1-4):115

We investigated the multifractal structure of the interevent times between successive earthquakes that occurred in Umbria-Marche, which is one of the most seismically active areas of central Italy. We used the Multifractal Detrended Fluctuation Analysis (MF-DFA), which permits detection of multifractality in nonstationary series. Analyzing the time evolution of the multifractal behaviour of the seismic sequence, a loss of multifractality during the aftershocks is revealed.  相似文献   

The 1538 Monte Nuovo eruption (Campi Flegrei,Italy)     

Mauro Di Vito  Lucio Lirer  Giuseppe Mastrolorenzo  Giuseppe Rolandi 《Bulletin of Volcanology》1987,49(4):608-615

On 29 September 1538 a week-long eruption began in Campi Flegrei forming a new volcano, Monte Nuovo. From contemporary accounts of the eruption, it has been possible to reconstruct the main phases of activity. These phases may be correlated with different depositional units identified in the field. The eruption opened with a hydromagmatic phase, during which a large amount of external water (meteoric or sea water) was able to interact with the magma. The exhaustion of the water supply and decrease in volatile content initiated a change in the dynamic conditions of eruption, which became more purely magmatic in character and less explosive.  相似文献