Interaction Between Waves and Turbulence Within the Nocturnal Boundary Layer     

Barbano  Francesco  Brogno  Luigi  Tampieri  Francesco  Di Sabatino  Silvana 《Boundary-Layer Meteorology》2022,185(1):35-61

Boundary-Layer Meteorology - Within the roughness sublayer (RSL) of dense urban canopies composed of uniformly distributed cuboids, the time and planar-averaged mean velocity profile exhibits an...  相似文献   

Late Quaternary aggradation rates and stratigraphic architecture of the southern Po Plain,Italy          下载免费PDF全文

Luigi Bruno  Alessandro Amorosi  Paolo Severi  Bianca Costagli 《Basin Research》2017,29(2):234-248

The Po River Basin, where accumulation and preservation of thick sedimentary packages are enhanced by high rates of tectonic subsidence, represents an ideal site to assess the relations between vertical changes in stratigraphic architecture and sediment accumulation rates. Based on a large stratigraphic database, a markedly contrasting stratigraphy of Late Pleistocene and Holocene deposits is reconstructed from the subsurface of the modern alluvial and coastal plains. Laterally extensive fluvial channel bodies and related pedogenically modified muds of latest Pleistocene age are unconformably overlain by Holocene overbank fines, grading seaward into paralic and nearshore facies associations. In the interfluvial areas, a stiff paleosol, dating at about 12.5–10 cal ky BP, marks the Pleistocene–Holocene boundary. Across this paleosol, aggradation rates (ARs) from 16 radiocarbon‐dated cores invariably show a sharp increase, from 0.1–0.9 mm year^?1 to 0.9–2.9 mm year^?1. Comparatively lower Pleistocene values are inferred to reflect fluvial activity under a low‐accommodation (lowstand and early transgressive) regime, whereas higher ARs during the Holocene are related to increasing accommodation under late transgressive and highstand conditions. Holocene sediment accumulation patterns vary significantly from site to site, and do not exhibit common trends. Very high accumulation rates (20–60 mm year^?1) are indicated by fluvial channel or progradational delta facies, suggesting that extremely variable spatial distribution of Holocene ARs was primarily controlled by autogenic processes, such as fluvial channel avulsion or delta lobe switching. Contrasting AR between uppermost Pleistocene and Holocene deposits also are reported from the interfluves of several coeval, alluvial‐coastal plain systems worldwide, suggesting a key control by allogenic processes. Sediment accumulation curves from adjacent incised valley fills show, instead, variable shapes as a function of the complex mechanisms of valley formation and filling.  相似文献   

Early Eocene orthophragminids and alveolinids from the Jafnayn Formation,N Oman: significance of Nemkovella stockari Less & Özcan, 2007 in Tethys     

Ercan Özcan  İftikhar Ahmed Abbasi  Katica Drobne  Abiraman Govindan  Luigi Jovane  Kamel Boukhalfa 《Geodinamica Acta》2016,28(3):160-184

The upper member of the Jafnayn Formation in Wadi Rusayl and Al Khoud, Seeb Area in north Oman contains Nemkovella stockari Less & Özcan, 2007, an Early Eocene orthophragminid recorded here for the first time from the Arabian Peninsula. N. stockari, the only orthophragminid identified in Jafnayn Formation, is quite distinct from any other species from Tethys in having spiral and orbitoidiform chambers around the isolepidine embryon developed before the onset of annular chambers. The Oman specimens exhibit equal-sized principal auxiliary chambers and symmetrical spirals and are assigned to N. stockari bejaensis Özcan, Boukhalfa & Scheibner, 2014, an advanced form of the N. stockari lineage. The associated alveolinids, revised in this study, rotaliids and other age-diagnostic foraminiferal taxa in the transgressive basal part of the upper member have enabled us to revise the age as middle Ilerdian (Early Eocene), assignable to SBZ 7/8 and 8; OZ 3/4. Integrating a new record of this species from Arabian Plate margin in Belen, S Turkey, and previous records from north Africa, N. stockari appears to be a diagnostic marker for the Early Eocene along the southern peri-Tethys platforms, facilitating the Tethyan correlation by orthophragminids. The palaeobiogeographic distribution of N. stockari is discussed.  相似文献   

The determination of deep temperatures by means of the CO-CO₂-H₂-H₂O geothermometer: an example using fumaroles in the Campi Flegrei, Italy. A comment     

Roberto Cioni  Luigi Marini 《Bulletin of Volcanology》1991,53(1):67-69

Three points raised in the paper by Tedesco and Sabroux (1987) are dealt with. (1) The inconsistency between the water partial pressure calculated by Tedesco and Sabroux (1987) and saturation pressure is due to the improper use of the water-gas-shift reaction as a geothermometer. In fact Tedesco and Sabroux (1987) do not take into account the distribution of gas species between the coexisting vapour and liquid phases. (2) The depth of the steam reservoir is evaluated by Tedesco and Sabroux (1987) in too simplistic a way. This matter should be treated with greater care owing to the high social impact of any consideration on the Phlegraean Fields system. (3) The reliability of carbon monoxide determination at the concentration level encountered at Solfatara depends on the collection method rather than on the gas-chromatographic technique.  相似文献   

An Efficient Tool for Wave Climate Analysis in European Coastal Waters     

Mauro Sclavo  Luigi Cavaleri  Stephen F. Barstow  Gerassimos A. Athanassoulis 《Marine Ecology》2002,23(S1):361-369

Abstract. We describe a software system that allows even an inexperienced user to estimate the wave statistics at any location along the European coastal zone. The system is composed of a solid, well verified data set, a geographical tool, a modelling section and a statistical package. Their use is fully transparent to the user.  相似文献   

Variability of Mediterranean coralligenous assemblages subject to local variation in sediment deposition     

Balata D  Piazzi L  Cecchi E  Cinelli F 《Marine environmental research》2005,60(4):403-421

This study tested whether the development of coralligenous assemblages on horizontal and vertical surfaces differed between localities of high and low sediment deposition. The development and structure of these assemblages varied in predictable ways according to the level of sediment deposition. These differences were largely independent of the orientation of substratum. Turfs were more extensive in areas of high sediment deposition while erect and encrusting algae were most extensive in areas of low sediment deposition. Encrusting invertebrates characterised vertical surfaces and were most extensive in areas of high sediment deposition. These results are consistent with studies from other temperate regions of the globe, suggesting that effects of sedimentation on temperate coasts are substantial and widespread.  相似文献   

A numerical model for the simulation of debris flow triggering,propagation and arrest     

D’Aniello  Andrea  Cozzolino  Luca  Cimorelli  Luigi  Della Morte  Renata  Pianese  Domenico 《Natural Hazards》2015,75(2):1403-1433

Natural Hazards - In this paper, it is described the development and the assessment of a 1D numerical procedure for the simulation of debris flow phenomena. The procedure focuses on: (1) the...  相似文献   

An algorithm for the objective reconstruction of rainfall events responsible for landslides   总被引：2，自引：2，他引：0  

Massimo Melillo  Maria Teresa Brunetti  Silvia Peruccacci  Stefano Luigi Gariano  Fausto Guzzetti 《Landslides》2015,12(2):311-320

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Three‐fold nature of coastal progradation during the Holocene eustatic highstand,Po Plain,Italy – close correspondence of stratal character with distribution patterns     

Alessandro Amorosi  Giulia Barbieri  Luigi Bruno  Bruno Campo  Tina M. Drexler  Wan Hong  Veronica Rossi  Irene Sammartino  Daniele Scarponi  Stefano Claudio Vaiani  Kevin M. Bohacs 《Sedimentology》2019,66(7):3029-3052

Although general trends in transgressive to highstand sedimentary evolution of river‐mouth coastlines are well‐known, the details of the turnaround from retrogradational (typically estuarine) to aggradational–progradational (typically coastal/deltaic) stacking patterns are not fully resolved. This paper examines the middle to late Holocene eustatic highstand succession of the Po Delta: its stratigraphic architecture records a complex pattern of delta outbuilding and coastal progradation that followed eustatic stabilization, since around 7·7 cal kyr bp . Sedimentological, palaeoecological (benthic foraminifera, ostracods and molluscs) and compositional criteria were used to characterize depositional conditions and sediment‐dispersal pathways within a radiocarbon‐dated chronological framework. A three‐stage progradation history was reconstructed. First, as soon as eustasy stabilized (7·7 to 7·0 cal kyr bp ), rapid bay‐head delta progradation (ca 5 m year^?1), fed mostly by the Po River, took place in a mixed, freshwater and brackish estuarine environment. Second, a dominantly aggradational parasequence set of beach‐barrier deposits in the lower highstand systems tract (7·0 to 2·0 cal kyr bp ) records the development of a shallow, wave‐dominated coastal system fed alongshore, with elongated, modestly crescent beaches (ca 2·5 m year^?1). Third, in the last 2000 years, the development of faster accreting and more rapidly prograding (up to ca 15 m year^?1) Po delta lobes occurred into 30 m deep waters (upper highstand systems tract). This study documents the close correspondence of sediment character with stratal distribution patterns within the highstand systems tract. Remarkable changes in sediment characteristics, palaeoenvironments and direction of sediment transport occur across a surface named the ‘A–P surface’. This surface demarcates a major shift from dominantly aggradational (lower highstand systems tract) to fully progradational (upper highstand systems tract) parasequence stacking. In the Po system, this surface also reflects evolution from a wave‐dominated to river‐dominated deltaic system. Identifying the A–P surface through detailed palaeoecological and compositional data can help guide interpretation of highstand systems tracts in the rock record, especially where facies assemblages and their characteristic geometries are difficult to discern from physical sedimentary structures alone.  相似文献   

Anatomy of the Holocene succession of the southern Venice lagoon revealed by very high-resolution seismic data     

Massimo Zecchin  Giuliano Brancolini  Luigi Tosi  Federica Rizzetto  Mauro Caffau  Luca Baradello 《Continental Shelf Research》2009

The southern portion of the Venice lagoon contains a relatively thick (up to 20 m) Holocene sedimentary body that represents a detailed record of the formation and evolution of the lagoon. New very high-resolution (VHR) seismic profiles provided a detailed investigation on depositional geometries, internal bounding surfaces and stratal relationships. These informations, combined with core analysis, allowed the identification of large- to medium-scale sedimentary structures (e.g. dunes, point bars), the corresponding sedimentary environment, and of retrogradational and progradational trends. In addition, the availability of dense seismic network produced a 3D reconstruction of the southern lagoon and the recognition of the along-strike and dip variability of the stratal architecture.  相似文献