Una semplice dimostrazione del teorema di bjerknes sulle circolazioni atmosferiche     

Prof. Dr. Luigi Castoldi 《Pure and Applied Geophysics》1950,18(1):160-161

Riassunto Si fa uso di una formula di derivazione di un integrale di superficie per dimostrare un teorema meteorologico diV. Bjerknes.

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Summary Use is made of a differentiation's formula for surface integrals in showing aV. Bjerknes' meteorological theorem.

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Sulla distribuzione della temperatura negli strati superiori della crosta terrestre     

Prof. Luigi Castoldi 《Pure and Applied Geophysics》1952,23(1):27-35

Riassunto Si determina la distribuzione teorica della temperatura in an gradino della crosta terrestre, quale si averebbe ai margini dei continenti o delle fosse cceaniche in condizioni di isotropia ed omogeneità del materiale; deducendone alcune particolarità.

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Summary The theoretical distribution of the temperature in a step-shaped part of the earth's crust has been determined, how it would be on the edge of the continents or the shelf of the oceans, under isotropic conditions and homogeneity of the material. Some inferences are deduced.

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On the interaction between ocean surface waves and seamounts     

Jeison Sosa  Luigi Cavaleri  Jesús Portilla-Yandún 《Ocean Dynamics》2017,67(12):1553-1565

Of the many topographic features, more specifically seamounts, that are ubiquitous in the ocean floor, we focus our attention on those with relatively shallow summits that can interact with wind-generated surface waves. Among these, especially relatively long waves crossing the oceans (swells) and stormy seas are able to affect the water column up to a considerable depth and therefore interact with these deep-sea features. We quantify this interaction through numerical experiments using a numerical wave model (SWAN), in which a simply shaped seamount is exposed to waves of different length. The results show a strong interaction that leads to significant changes in the wave field, creating wake zones and regions of large wave amplification. This is then exemplified in a practical case where we analyze the interaction of more realistic sea conditions with a very shallow rock in the Yellow Sea. Potentially important for navigation and erosion processes, mutatis mutandis, these results are also indicative of possible interactions with emerged islands and sand banks in shelf seas.  相似文献   

Mechanisms linking active rock glaciers and impounded surface water formation in high‐mountain areas          下载免费PDF全文

Nicola Colombo  Luigi Sambuelli  Cesare Comina  Chiara Colombero  Marco Giardino  Stephan Gruber  Gaetano Viviano  Livia Vittori Antisari  Franco Salerno 《地球表面变化过程与地形》2018,43(2):417-431

Rock glaciers are slowly flowing mixtures of debris and ice occurring in mountains. They can represent a reservoir of water, and melting ice inside them can affect surface water hydrochemistry. Investigating the interactions between rock glaciers and water bodies is therefore necessary to better understand these mechanisms. With this goal, we elucidate the hydrology and structural setting of a rock glacier–marginal pond system, providing new insights into the mechanisms linking active rock glaciers and impounded surface waters. This was achieved through the integration of waterborne geophysical techniques (ground penetrating radar, electrical resistivity tomography and self‐potentials) and heat tracing. Results of these surveys showed that rock glacier advance has progressively filled the valley depression where the pond is located, creating a dam that could have modified the level of impounded water. A sub‐surface hydrological window connecting the rock glacier to the pond was also detected, where an inflow of cold and mineralised underground waters from the rock glacier was observed. Here, greater water contribution from the rock glacier occurred following intense precipitation events during the ice‐free season, with concomitant increasing electrical conductivity values. The outflowing dynamic of the pond is dominated by a sub‐surface seepage where a minor fault zone in bedrock was found, characterised by altered and highly‐fractured rocks. The applied approach is evaluated here as a suitable technique for investigating logistically‐complex hydrological settings which could be possibly transferred to wider scales of investigation. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Advances and Practices on the Research,Prevention and Control of Land Subsidence in Coastal Cities     

YAN Xuexin  YANG Tianliang  XU Yan  Luigi TOSI  Esther STOUTHAMER  Heri ANDREAS  Philip MINDERHOUD  Anirut LADAWADEE  Ramon HANSSEN  Gilles ERKENS  Pietro TEATINI  LIN Jinxin  Roberta BONì  Jarinya CHIMPALEE  HUANG Xinlei  Cristina Da LIO  Claudia MEISINA  Francesco ZUCCA 《《地质学报》英文版》2020,94(1):162-175

Land subsidence severely threatens most of the coastal plains around the world where high productive industrial and agricultural activities and urban centers are concentrated. Coastal subsidence damages infrastructures and exacerbates the effect of the sea-level rise at regional scale. Although it is a well-known process, there is still much more to be improved on the monitoring, mapping and modeling of ground movements, as well as the understanding of controlling mechanisms. The International Geoscience Programme recently approved an international project (IGCP 663) aiming to bring together worldwide researchers to share expertise on subsidence processes typically occurring in coastal areas and cities, including basic research, monitoring and observation, modelling and management. In this paper, we provide the research communities and potential stakeholders with the basic information to join the participating teams in developing this project. Specifically, major advances on coastal subsidence studies and information on well-known and new case studies of land subsidence in China, Italy, The Netherlands, Indonesia, Vietnam and Thailand are highlighted and summarized. Meanwhile, the networking, dissemination, annual meeting and field trip are briefly introduced.  相似文献   

Strict positive definiteness under axial symmetry on the sphere     

Bissiri  Pier Giovanni  Peron  Ana Paula  Porcu  Emilio 《Stochastic Environmental Research and Risk Assessment (SERRA)》2020,34(5):723-732

Stochastic Environmental Research and Risk Assessment - Axial symmetry for covariance functions defined over spheres has been a very popular assumption for climate, atmospheric, and environmental...  相似文献   

Modeling multiple wave systems in the eastern equatorial Pacific     

Portilla-Yandún  Jesús  Salazar  Andrés  Sosa  Jeison  Latandret  Sadid  Cavaleri  Luigi 《Ocean Dynamics》2020,70(7):977-990

Ocean Dynamics - While moderate wind and wave conditions prevail in the eastern equatorial Pacific, modeling waves in this area remains challenging due to the presence of multiple wave systems...  相似文献   

The performance of churches in the 2012 Emilia earthquakes     

Luigi Sorrentino  Laura Liberatore  Luis D. Decanini  Domenico Liberatore 《Bulletin of Earthquake Engineering》2014,12(5):2299-2331

In this study the damage suffered by churches during the 2012 Emilia seismic sequence in Italy is analysed, based on surveys and inspections carried out in the area. Similarly to what was observed after other Italian earthquakes, the damage to churches was severe. However, the Emilia churches present some characteristic features such as the use of unreinforced clay brick masonry. In order to appropriately address the performance of this class of buildings, typical architectural layouts and construction techniques are described. Such techniques are interpreted also in the light of the local seismic catalogue. Fifty churches are then selected and their damage is studied, with reference to typical local-collapse mechanisms of different macro-elements. The study highlights that the damage is often concentrated at the top section of the façade, in the clerestory walls, in the vaults and in the bell towers. Structural analyses are performed to explain some of the observations. The overturning of the top section of the façade is analytically addressed, modelling the friction interlocking. With reference to the case study of San Francesco in Mirandola, non-linear static and dynamic analyses allow us to correlate the directionality of damage to the higher seismic demand along the NS direction, to point out the negligible role of the large vertical component of ground motion and to emphasise the relevance of the buttresses for the seismic response of the façade.  相似文献   

Vent temperature trends at the Vulcano Fossa fumarole field: the role of permeability     

Andrew Harris  Salvatore Alparone  Alessandro Bonforte  Jonathan Dehn  Salvatore Gambino  Luigi Lodato  Letizia Spampinato 《Bulletin of Volcanology》2012,74(6):1293-1311

Between 1994 and 2010, we completed 16 thermal surveys of Vulcano’s Fossa fumarole field (Aeolian Islands, Italy). In each survey, between 400 and 1,200 vent temperatures were collected using a thermal infrared thermometer from distances of ～1?m. The results show a general decrease in average vent temperature during 1994–2003, with the average for the entire field falling from ～220°C in 1994 to ～150°C by 2003. However, between 2004 and 2010, we witnessed heating, with the average increasing to ～190°C by 2010. Alongside these annual-scale field-wide trends, we record a spatial re-organisation of the fumarole field, characterised by shut down of vent zones towards the crater floor, matched by rejuvenation of zones located towards the crater rim. Heating may be expected to be associated with deflation because increased amounts of vaporisation will remove volume from the hydrothermal system Gambino and Guglielmino (J Geophys Res 113:B07402, 2008). However, over the 2004–2010 heating period, no ground deformation was observed. Instead, the number of seismic events increased from a typical rate of 37 events per month during 1994–2000 to 195 events per month during 2004–2010. As part of this increase, we noticed a much greater number of high-frequency events associated with rock fracturing. We thus suggest that the heating event of 2004–2010 was the result of changed permeability conditions, rather than change in the heat supply from the deeper magmatic source. Within this scenario, cooling causes shut down of lower sectors and re-establishment of pathways located towards the crater rim, causing fracturing, increased seismicity and heat flow in these regions. This is consistent with the zone of rejuvenation (which lies towards and at the rim) being the most favourable location for fracturing given the stress field of the Fossa cone Sch?pa et al. (J Volcanol Geotherm Res 203:133–145, 2011); it is also the most established zone, having been active at least since the early twentieth century. Our data show the value of deploying multi-disciplinary geophysical campaigns at degassing (fumarolic) hydrothermal systems. This allows more complete and constrained understanding of the true heat loss dynamics of the system. In the case study presented here, it allows us to distinguish true heating from apparent heating phases. While the former are triggered from the bottom-up, i.e. they are driven by increases in heat supply from the magmatic source, the latter are triggered from the top-down, i.e. by changing permeability conditions in the uppermost portion of the system to allow more efficient heat flow over zones predisposed to fracturing.  相似文献   

Genetic variability of the blue and red shrimp Aristeus antennatus in the Western Mediterranean Sea inferred by DNA microsatellite loci     

Rita Cannas  Flavio Sacco  Maria Cristina Follesa  Andrea Sabatini  Marco Arculeo  Sabrina Lo Brutto  Teresa Maggio  Anna Maria Deiana  Angelo Cau 《Marine Ecology》2012,33(3):350-363

Genetic variation at eight microsatellite loci was studied in nine populations of the blue and red shrimp Aristeus antennatus to investigate whether distinct stocks are present in the Western Mediterranean Sea. A high level of gene flow and no evidence of genetic partitioning were discovered. No significant variation was found (F_ST = 0.00673, P-value = 0.067) even when shrimps from exploited and those from deep-water unexploited grounds were compared. No evidence of reduction or expansion of population size in the recent past was found, as indicated by the bottleneck and interlocus g-tests. Our results are consistent with previous studies using mitochondrial gene methods and allozymes, indicating that, for this species, extensive pelagic larval dispersal and adult migration are probably responsible for the genetic homogeneity observed. In particular, due to a different bathymetric distribution of males and females, reported to be associated with different water masses and hence with possible differential dispersal capacity between sexes, the hypothesis of sex-biased dispersal was tested. Mean values of corrected assignment indices and mean relatedness values were higher for males, suggesting that females are the more widely dispersing sex. Molecular assessment of A. antennatus from the Western Mediterranean provides data of biological and evolutionary interest for the successful management of such a highly valuable fishery resource.  相似文献