Solute transport scales in an unsaturated stony soil     

Antonio Coppola  Alessandro ComegnaGiovanna Dragonetti  Miles DyckAngelo Basile  Nicola LamaddalenaMohamed Kassab  Vincenzo Comegna 《Advances in water resources》2011,34(6):747-759

Solute transport parameters are known to be scale-dependent due mainly to the increasing scale of heterogeneities with transport distance and with the lateral extent of the transport field examined. Based on a transect solute transport experiment, in this paper we studied this scale dependence by distinguishing three different scales with different homogeneity degrees of the porous medium: the observation scale, transport scale and transect scale. The main objective was to extend the approach proposed by van Wesenbeeck and Kachanoski to evaluating the role of textural heterogeneities on the transition from the observation scale to the transport scale. The approach is based on the scale dependence of transport moments estimated from solute concentrations distributions. In our study, these moments were calculated starting from time normalized resident concentrations measured by time domain reflectometry (TDR) probes at three depths in 37 soil sites 1 m apart along a transect during a steady state transport experiment. The Generalized Transfer Function (GTF) was used to describe the evolution of apparent solute spreading along the soil profile at each observation site by analyzing the propagation of the moments of the concentration distributions. Spectral analysis was used to quantify the relationship between the solid phase heterogeneities (namely, texture and stones) and the scale dependence of the solute transport parameters. Coupling the two approaches allowed us to identify two different transport scales (around 4-5 m and 20 m, respectively) mainly induced by the spatial pattern of soil textural properties. The analysis showed that the larger transport scale is mainly determined by the skeleton pattern of variability. Our analysis showed that the organization in hierarchical levels of soil variability may have major effects on the differences between solute transport behavior at transport scale and transect scale, as the transect scale parameters will include information from different scales of heterogeneities.  相似文献   

The 183-WSL fast rain rate retrieval algorithm: Part I: Retrieval design     

Sante Laviola  Vincenzo Levizzani 《Atmospheric Research》2011,99(3-4):443-461

The Water vapour Strong Lines at 183 GHz (183-WSL) fast retrieval method retrieves rain rates and classifies precipitation types for applications in nowcasting and weather monitoring. The retrieval scheme consists of two fast algorithms, over land and over ocean, that use the water vapour absorption lines at 183.31 GHz corresponding to the channels 3 (183.31 ± 1 GHz), 4 (183.31 ± 3 GHz) and 5 (183.31 ± 7 GHz) of the Advanced Microwave Sounding Unit module B (AMSU-B) and of the Microwave Humidity Sounder (MHS) flying on NOAA-15-18 and Metop-A satellite series, respectively.The method retrieves rain rates by exploiting the extinction of radiation due to rain drops following four subsequent steps. After ingesting the satellite data stream, the window channels at 89 and 150 GHz are used to compute scattering-based thresholds and the 183-WSLW module for rainfall area discrimination and precipitation type classification as stratiform or convective on the basis of the thresholds calculated for land/mixed and sea surfaces. The thresholds are based on the brightness temperature difference Δ_win = T_B89 ? T_B150 and are different over land (L) and over sea (S): cloud droplets and water vapour (Δ_win < 3 K L; Δ_win < 0 K S), stratiform rain (3 K < Δ_win < 10 K L; 0 K < Δ_win < 10 K S), and convective rain (Δ_win > 10 K L and S). The thresholds, initially empirically derived from observations, are corroborated by the simulations of the RTTOV radiative transfer model applied to 20000 ECMWF atmospheric profiles at midlatitudes and the use of data from the Nimrod radar network. A snow cover mask and a digital elevation model are used to eliminate false rain area attribution, especially over elevated terrain. A probability of detection logistic function is also applied in the transition region from no-rain to rain adjacent to the clouds to ensure continuity of the rainfall field. Finally, the last step is dedicated to the rain rate retrieval with the modules 183-WSLS (stratiform) and 183WSLC (convective), and the module 183-WSL for total rainfall intensity derivation.A comparison with rainfall retrievals from the Goddard Profiling (GPROF) TRMM 2A12 algorithm is done with good results on a stratiform and hurricane case studies. A comparison is also conducted with the MSG-based Precipitation Index (PI) and the Scattering Index (SI) for a convective-stratiform event showing good agreement with the 183-WSLC retrieval. A complete validation of the product is the subject of Part II of the paper.  相似文献   

Rock magnetic,petrographic and dielectric characterization of prehistoric Amerindian potsherds from Venezuela     

Myriam Andrea Rada Torres  Vincenzo Costanzo-Álvarez  Milagrosa Aldana  Nery Suárez  Corina Campos  Maria Magdalena Mackowiak-Antczak  María Carmela Brandt 《Studia Geophysica et Geodaetica》2011,55(4):717-736

Rock magnetic, petrographic and dielectric analyses were carried out, in a number of archeological ceramic potsherds, in order to characterize the different manufacturing techniques used by Prehistoric Venezuelan Amerindian potters. Samples were excavated in 7 Venezuelan islands and ascribed to distinct cultural groups on purely stylistic grounds (i.e. Valencioide, Ocumaroide, Dabajuroide and Unknown). Mean coercivity values were determined through a direct signal analyses (DSA) applied to isothermal remanent magnetization (IRM) acquisition curves. Logarithmic plots of these mean coercivities are the best quantitative means to classify diverse ceramics. The mean coercivity values seem to group the samples according to the manufacturing development. These values also seem to discriminate the samples provenance, indeed, this plot displays a good grouping of data for samples presumably manufactured by the same culture but excavated at different locations. Thermomagnetic cycles supply helpful information about original ceramic firing conditions. The irreversibility parameter (IP) for thermomagnetic curves (heating and cooling), serves as an indicator of the amount of organic matter burnt during original pottery firing. The IP for a number of pottery samples from Venezuelan islands and mainland, with ages ranging between 300 BC to 1500 AD, might suggest a possible increasing trend in time towards the complete reversibility line of IP = 0. Most samples, independently of age and cultural group, have IP values that suggest that most open fires, used by primitive Venezuelan Amerindian potters, had enough ventilation and oxidizing atmospheres. A scatter plot of maximum current depolarization temperatures versus natural remanent magnetization (NRM) suggests a complex non-linear relationship between these two parameters most likely due to the fact that both, dielectric and rock magnetic data, are linked to pore-related features.  相似文献   

Sea Ice, 2nd edn     

Vincenzo Saggiomo  Olga Mangoni  Antonio Pusceddu 《Marine Ecology》2011,32(1):132-133

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Standard candles from the Gaia perspective     

Laurent Eyer  Lovro Palaversa  Nami Mowlavi  Pierre Dubath  Richard I. Anderson  Dafydd W. Evans  Thomas Lebzelter  Vincenzo Ripepi  Laszlo Szabados  Silvio Leccia 《Astrophysics and Space Science》2012,341(1):207-214

The ESA Gaia mission will bring a new era to the domain of standard candles. Progresses in this domain will be achieved thanks to unprecedented astrometric precision, whole-sky coverage and the combination of photometric, spectrophotometric and spectroscopic measurements. The fundamental outcome of the mission will be the Gaia catalogue produced by the Gaia Data Analysis and Processing Consortium (DPAC), which will contain a variable source classification and specific properties for stars of specific variability types. We review what will be produced for Cepheids, RR Lyrae, Long Period Variable stars and eclipsing binaries.  相似文献   

Raw Materials for Archaeological Pottery from the Campania Region of Italy: A Petrophysical Characterization     

Alberto De Bonis  Celestino Grifa  Giuseppe Cultrone  Pantaleone De Vita  Alessio Langella  Vincenzo Morra 《Geoarchaeology》2013,28(5):478-503

We performed petrophysical analyses on 34 clayey samples of different geological origin within the Campania region of Italy in order to determine possible sources of raw materials used to produce ancient pottery. Possible raw material sources can be grouped into high‐CaO clays (HCC) and low‐CaO clays (LCC). HCC are mainly represented by more recent (Miocene‐Pleistocene) basinal sediments whereas LCC tend to be associated with basinal, alluvial, and pyroclastic deposits. A chemical comparison between clayey raw materials, modern ceramic replicas, and Campanian archaeological ceramics of several typologies (common ware, cooking ware, fine tableware, amphorae, and bricks) from 8th century B.C. to the Middle Ages (a total of 350 ceramic samples) indicates that HCC were extensively used for common wares and that these were either mixed with temper or levigated. In contrast, most of the LCC were used for the production of cookware. We also analyzed the technological potential of the sampled raw materials, taking into consideration their actual and possible uses. We observed that most HCC deposits were well suited for tableware and amphorae, whereas LCC were better for cookware and some fine tableware.  相似文献   

The age of the Paludi Formation: a major constraint to the beginning of the Apulia-verging orogenic transport in the northern sector of the Calabria–Peloritani Arc     

Glauco Bonardi  Paola de Capoa  Angelida Di Staso  Vincenzo Perrone  Maurizio Sonnino  Mario Tramontana 《地学学报》2005,17(4):331-337

A stratigraphic revision of the Paludi Formation, cropping out in Northern Calabria on the north-eastern side of Sila Massif, has confirmed that it has been deposited between two main tectonic phases. Actually the formation is involved only by top to the north-east thrusts, different from those separating the crystalline and ophiolitic nappes of Northern Calabria, and rests unconformably on the Sila Unit, the uppermost nappe of the tectonic stack. In the frame of the interpretation of Northern Calabria as a fragment of the Alps, the Paludi Formation play the role of a deposit post-dating the eo-alpine tectonic phases and pre-dating the Apenninic orogenic transport. Therefore the Aquitanian age of the formation, obtained by nannofloras analyses, can be considered the minimum age to the Apulia-verging orogenic transport, witnessed by top to north-east thrusts. It fairly corresponds to the age referred to the Lucanian ocean closure.  相似文献   

Seismology of the solar atmosphere   总被引：1，自引：0，他引：1  

Wolfgang Finsterle  Stuart M. Jefferies  Alessandro Cacciani  Paolo Rapex  Cynthia Giebink  Allister Knox  Vincenzo DiMartino 《Solar physics》2004,220(2):317-331

We describe a new instrument for seismically probing the properties of the Sun's lower atmosphere, and present some first results from an observational campaign carried out at the geographic South Pole during the austral summer of 2002/2003. A preliminary analysis of the data (simultaneous, high-cadence observations of the velocity signals from the photosphere and low chromosphere) shows that the well-known suppression of acoustic power in regions of strong magnetic field, and enhancement of high-frequency power around active regions (acoustic halos), are both consistent with a spreading out of the magnetic field lines with increasing height in the atmosphere. The data have also revealed some unexpected wave behavior. First, evanescent-like waves are found at frequencies substantially above the acoustic cut-off frequency in regions of intermediate magnetic field. Second, upward- and downward-propagating waves are detected in areas of strong magnetic field such as sunspots and plage: even at frequencies below the acoustic cut-off frequency. Third, the wave behavior in regions of strong magnetic field can change over periods of a few hours from propagating to evanescent. While we have no concrete explanation for the first two results, the latter result opens up the question of whether sound waves are involved in short-term events such as flares or CME's.  相似文献   

Thermohaline circulation sensitivity to intermediate-level anomalies     

Vincenzo Artale  Sandro Calmanti  Alfonso Sutera 《地球，A辑:动力气象学与海洋学》2002,54(2):159-174

Abstract A two-dimensional Boussinesq ocean model has been used to investigate the effect of intermediate-level thermal and saline anomalies on the known multiple equilibria structure of the thermohaline circulation. These anomalies are taken as a crude representation of the Mediterranean outflow in the Atlantic Ocean. The associated perturbation drives the system towards an overturning which resembles the present average Atlantic thermohaline circulation. The sensitivity to the depth at which the anomaly is placed is also investigated. We found that near-surface anomalies are more efficient in affecting the structure of the equilibria.  相似文献   

Optical characterization of laser ablated silicates     

Rosario Brunetto  Ted L. Roush  Vincenzo Orofino 《Icarus》2007,191(1):381-393

We perform an optical characterization of UV laser ablated silicates (olivine, pyroxene), starting from their reflectance spectra in the 0.3-2.5 μm spectral range. The goal is to provide useful tools to model space weathering effects on surfaces of asteroids and TNOs (trans-neptunian objects). We determine that the reddening and darkening spectral trend is compatible with the Hapke's space weathering model, using the optical constants of metallic iron in a silicate matrix. This result is supported by new magnetic susceptibility measurements on laser ablated orthopyroxene. We also investigate the potential contribution of formation of amorphous silicates in the process. Applying our results to silicate-rich surfaces in the Solar System, we investigate the possibility of a weathered olivine component on the surface of Centaur 5145 Pholus. Inclusion of this component slightly decreases the amount of complex organics and water ice from those previously estimated. Thus, the current Pholus spectrum is consistent with the presence of either unweathered or weathered olivine, or potentially both materials.  相似文献