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181.
Spatio‐temporal variability of water and energy fluxes – a case study for a mesoscale catchment in pre‐alpine environment 下载免费PDF全文
Luitpold Hingerl Harald Kunstmann Sven Wagner Matthias Mauder Jan Bliefernicht Riccardo Rigon 《水文研究》2016,30(21):3804-3823
Water and energy fluxes at and between the land surface, the subsurface and the atmosphere are inextricably linked over all spatio‐temporal scales. Our research focuses on the joint analysis of both water and energy fluxes in a pre‐alpine catchment (55 km2) in southern Germany, which is part of the Terrestrial Environmental Observatories (TERENO). We use a novel three‐dimensional, physically based and distributed modelling approach to reproduce both observed streamflow as an integral measure for water fluxes and heat flux and soil temperature measurements at an observation location over a period of 2 years. While heat fluxes are often used for comparison of the simulations of one‐dimensional land surface models, they are rarely used for additional validation of physically based and distributed hydrological modelling approaches. The spatio‐temporal variability of the water and energy balance components and their partitioning for dominant land use types of the study region are investigated. The model shows good performance for simulating daily streamflow (Nash–Sutcliffe efficiency > 0.75). Albeit only streamflow measurements are used for calibration, the simulations of hourly heat fluxes and soil temperatures at the observation site also show a good performance, particularly during summer. A limitation of the model is the simulation of temperature‐driven heat fluxes during winter, when the soil is covered by snow. An analysis of the simulated spatial fields reveals heat flux patterns that reflect the distribution of the land use and soil types of the catchment. The water and energy partitioning is characterized by a strong seasonal cycle and shows clear differences between the selected land use types. Copyright © 2016 The Authors Hydrological Processes Published by John Wiley & Sons Ltd. 相似文献
182.
Riccardo Cesaroni 《Astrophysics and Space Science》2005,295(1-2):5-17
According to theory, stars more massive than 8 M must form while still accreting material from the surrounding parental cloud: at this stage radiation pressure should reverse the infall thus preventing further growth of the stellar mass. After illustrating the two models proposed to solve this problem (accretion and coalescence), we review the observational evidence pro/contra such models, focusing on the kinematics of the molecular gas where the massive (proto)stars are embedded as the best tool to shed light on the formation mechanism. Special attention is devoted to the phenomena of infall, outflow, and rotation, concluding that the recent detection of rotating disks in massive young stellar objects is the best evidence so far in favour of the accretion model. 相似文献
183.
Diana Dell’Arciprete Chiara Vassena Fulvia Baratelli Mauro Giudici Riccardo Bersezio Fabrizio Felletti 《Hydrogeology Journal》2014,22(4):761-778
In porous aquifers, groundwater flow and solute transport strongly depend on the sedimentary facies distribution at fine scale, which determines the heterogeneity of the conductivity field; in particular, connected permeable sediments could form preferential flow paths. Therefore, properly defined statistics, e.g. total and intrinsic facies connectivity, should be correlated with transport features. In order to improve the assessment of the relevance of this relationship, some tests are conducted on two ensembles of equiprobable realizations, obtained with two different geostatistical simulation methods—sequential indicator simulation and multiple point simulation (MPS)—from the same dataset, which refers to an aquifer analogue of sediments deposited in a fluvial point-bar/channel association. The ensembles show different features; simulations with MPS are more structured and characterised by preferential flow paths. This is confirmed by the analysis of transport connectivities and by the interpretation of data from numerical experiments of conservative solute transport with single and dual domain models. The use of two ensembles permits (1) previous results obtained for single realizations to be consolidated on a more firm statistical basis and (2) the application of principal component analysis to assess which quantities are statistically the most relevant for the relationship between connectivity indicators and flow and transport properties. 相似文献
184.
This paper describes the numerical simulation of two dynamic centrifuge tests on reduced scale models of shallow tunnels in dry sand, carried out using both an advanced bounding surface plasticity constitutive soil model and a simple Mohr–Coulomb elastic-perfectly plastic model with embedded nonlinear and hysteretic behaviour. The predictive capabilities of the two constitutive models are assessed by comparing numerical predictions and experimental data in terms of accelerations at several positions in the model, and bending moment and hoop forces in the lining. Computed and recorded accelerations match well, and a quite good agreement is achieved also in terms of dynamic bending moments in the lining, while numerical and experimental values of the hoop force differ significantly with one another. The influence of the contact assumption between the tunnel and the soil is investigated by comparing the experimental data and the numerical results obtained with different interface conditions with the analytical solutions. The overall performance of the two models is very similar indicating that at least for dry sand, where shear-volumetric coupling is less relevant, even a simple model can provide an adequate representation of soil behaviour under dynamic conditions. 相似文献
185.
Paolo Mazzetti Giuseppe Puglisi Luca D’Auria Roberto Roncella Danilo Reitano Riccardo Merenda Stefano Nativi 《Earth Science Informatics》2017,10(4):443-455
This paper presents the Virtual Research Environment (VRE) enabling two European GEO Geohazard Supersites in Italy. According to GEO (Group on Earth Observation) vision, Geohazard Supersites provide access to spaceborne and in-situ geophysical data and models for selected sites prone to natural hazards –noticeably, earthquakes and volcano eruptions. The VRE was implemented in the framework of the Mediterranean Supersite Volcanoes (MED-SUV) project, funded by the European Commission. MED-SUV realized one of the European supersite demonstrators covering the two Permanent Supersites selected in Italy: Mt. Etna and Campi Flegrei/Vesuvius. The MED-SUV VRE provides advanced services for heterogeneous data and information management and sharing. MED-SUV started identifying the main supersite requirements including: the interoperability with existing data/information supply systems, the support of policy-based access control, the access to processing capabilities provided by external platforms, the management resources for publishing and sharing new products, the integration with significant global systems such as GEOSS and EPOS. MED-SUV adopted a System of Systems (SoS) approach to address interoperability with the identified heterogeneous systems supplying data and information. The SoS approach is based on a brokering architecture, where a specialized component (i.e the MED-SUV Broker: MSB) connects the existing and next-coming data sources leaving them autonomous. MSB carries out all the necessary mediation and harmonization tasks exposing standard interfaces enabling the interconnection with external systems like GEOSS and EPOS. In addition, MSB is accessible via a JavaScript library implementing Web APIs to facilitate the development of Web and mobile applications. 相似文献
186.
Teresa Salvatici Stefano Morelli Veronica Pazzi William Frodella Riccardo Fanti 《山地科学学报》2017,14(4):636-648
On 4th November 2010, a debris flow detached from a large debris cover accumulated above the lowermost portion of the Rotolon landslide (Vicentine Pre-Alps, NE Italy) and channelized in the valley below within the Rotolon Creek riverbed. Such event evolved into a highly mobile and sudden debris flow, damaging some hydraulic works and putting at high risk four villages located along the creek banks. A monitoring campaign was carried out by means of a ground based radar interferometer (GB-InSAR) to evaluate any residual displacement risk in the affected area and in the undisturbed neighbouring materials. Moreover, starting from the current slope condition, a landslide runout numerical modelling was performed by means of DAN-3D code to assess the impacted areas, flow velocity, and deposit distribution of the simulated events. The rheological parameters necessary for an accurate modelling were obtained through the back analysis of the 2010 debris flow event. Back analysis was calibrated with all of the available terrain data coming from field surveys and ancillary documents, such as topographic, geomorphological and geological maps, with pre- and post-event LiDAR derived DTMs, and with orthophotos. Finally, to identify new possible future debris flow source areas as input data for the new modelling, all the obtained terrain data were reanalysed and integrated with the GB-InSAR displacement maps; consequently, new simulations were made to forecast future events. The results show that the integration of the selected modelling technique with ancillary data and radar displacement maps can be a very useful tool for managing problems related to debris flow events in the examined area. 相似文献
187.
Riccardo Tribuzio Massimo Tiepolo Riccardo Vannucci Piero Bottazzi 《Contributions to Mineralogy and Petrology》1999,134(2-3):123-133
The trace element distribution in three selected olivine-bearing gabbros from the Northern Apennine ophiolites has been determined.
These rocks consist of euhedral plagioclase and olivine, and subhedral to poikilitic clinopyroxene. Fe-Ti-oxides, titanian
pargasite, orthopyroxene and apatite occur as interstitial accessory minerals. Plagioclase, clinopyroxene and accessory minerals
were analysed for rare earth (REE) and selected trace elements by secondary ion mass spectrometry. Both plagioclase and clinopyroxene
are compositionally zoned. The plagioclase rims have slightly lower anorthite component and higher light REE (LREE), Ba and
K than the cores. Likewise, the clinopyroxene rims show a slight Mg and Cr decrease, and a marked increase in Zr, REE and
Y relative to the core. The rims of plagioclase and clinopyroxene, Fe-Ti-oxides, apatite and titanian pargasite most likely
formed through post-cumulus fractional crystallization of interstitial liquid. It is argued that such interstitial liquid
had an exotic component, probably related to the infiltration of highly evolved, slightly LREE enriched liquid in the cumulate
pile. On the basis of mass balance calculations, we show that Fe-Ti-oxides play an important role in the Ti budget of the
whole rock, as does apatite for LREE.
Received: 15 January 1998 / Accepted: 22 September 1998 相似文献
188.
Oceanographic Characteristics of a Multi-Specific Fishing Ground of the Central South Brazil Bight 总被引:1,自引:0,他引:1
In the Central South Brazil Bight, a multispecific demersal trawl fishery is conducted by trawlers licensed for the industrial pink shrimp (Penaeus paulensis and Penaeus brasiliensis) fishery. In addition to the pink shrimp, many by-catch species have become increasingly valued in the last two decades. In spite of the importance of this multispecific fishery, the oceanographic characteristics of the inner continental shelf, onshore the 100 m isobath, are poorly known. In this paper we present, for the fist time, monthly oceanographic records taken from December 1995 to May 1997 with the R/V ‘Diadorim’ at two of the main fishing grounds of this region. Water temperature data showed the formation of a strong thermocline during summer, from November to April. This thermal gradient, due to the South Atlantic central water (SACW) intrusion that reaches these shallow waters, disappeared with the homogenization of the water column during autumn and winter, from May to September. This cold and low salinity water does not originate from local river discharges, but also represents an advection of sub-Antartic water mass. After this and during spring, a new thermocline develops, reaching its maximal expression from February to March. A maximal gradient was registered in February 1997, when the temperature dropped from 26°C at 7 m to 16°C at 14 m depth. This result shows that the SACW intrusion is a large-scale phenomenon that regularly influences the whole inner continental shelf up to 20 m. Demersal fishing grounds located in this area were covered during summer by a cold and nutrient-rich mass of water that resulted in an unusual maximum of chlorophyll a values near the bottom (30 m). The homogenization of the water column and the presence of another cold water mass during winter resulted in a strong semi-annual thermal cycle on the bottom. The role of this important oceanographic process in fishery production and dynamics deserves further investigation, but the data presented here show evidence for the importance of this phenomenon. 相似文献
189.
Marotta Anna Maria Seitz Kurt Barzaghi Riccardo Grombein Thomas Heck Bernhard 《Studia Geophysica et Geodaetica》2019,63(3):321-344
Studia Geophysica et Geodaetica - Forward modelling in the space domain is a very important task in geodesy and other geosciences. From topographical or isostatic information in the form of digital... 相似文献
190.
Thibault Duretz Riccardo Asti Yves Lagabrielle Jean-Pierre Brun Anthony Jourdon Camille Clerc Benjamin Corre 《Basin Research》2020,32(4):652-667
The preshortening Cretaceous Pyrenean Rift is an outstanding geological laboratory to investigate the effects of a pre-rift salt layer at the sedimentary base on lithospheric rifting. The occurrence of a pre-rift km-scale layer of evaporites and shales promoted the activation of syn-rift salt tectonics from the onset of rifting. The pre- and syn-rift sediments are locally affected by high-temperature metamorphism related to mantle ascent up to shallow depths during rifting. The thermo-mechanical interaction between décollement along the pre-existing salt layer and mantle ascent makes the Cretaceous Pyrenean Rifting drastically different from the type of rifting that shaped most Atlantic-type passive margins where salt deposition is syn-rift and gravity-driven salt tectonics has been postrift. To unravel the dynamic evolution of the Cretaceous Pyrenean Rift, we carried out a set of numerical models of lithosphere-scale extension, calibrated using the available geological constraints. Models are used to investigate the effects of a km-scale pre-rift salt layer, located at the sedimentary cover base, on the dynamics of rifting. Our results highlight the key role of the décollement layer at cover base that can alone explain both salt tectonics deformation style and high-temperature metamorphism of the pre-rift and syn-rift sedimentary cover. On the other hand, in the absence of décollement, our model predicts symmetric necking of the lithosphere devoid of any structure and related thermal regime geologically relevant to the Pyrenean case. 相似文献