Aspects of stratospheric long-term changes induced by ozone depletion     

Chiara Cagnazzo  Chantal Claud  Sylvia Hare 《Climate Dynamics》2006,27(1):101-111

The effect of the stratospheric ozone depletion on the thermal and dynamical structure of the middle atmosphere is assessed using two 5-member ensembles of transient GCM simulations; one including linear trends in ozone, the other not, for the 1980–1999 period. Simulated temperatures and observations are in good agreement in terms of mean values, autocorrelations and cross correlations. Annual-mean and seasonal temperature trends have been calculated using the same statistical analysis. Simulations show that ozone trends are responsible for reduced wave activity in the Arctic lower stratosphere in February and March, confirming both the role of dynamics in controlling March temperatures and a recently proposed mechanism whereby Arctic ozone depletion causes the reduction in wave activity entering the lower stratosphere. Changes in wave activity are consistent with an intensification of the polar vortex at the time of ozone depletion and with a weakened Brewer–Dobson circulation: A decrease of the dynamical warming/cooling associated with the descending/ascending branch of the wintertime mean residual circulation at high/low latitudes has been obtained through the analysis of temperature observations (1980–1999). Ozone is responsible of about one third of the decrease of this dynamical cooling at high latitudes. An increase in the residual mean circulation is seen in the observations for the 1965–1980 period.  相似文献   

UNESCO World Heritage sites in Italy affected by geological problems, specifically landslide and flood hazard   总被引：2，自引：1，他引：2  

Giorgio Lollino  Chiara Audisio 《Landslides》2006,3(4):311-321

A National Research Council, Research Institute for Hydrogeological Protection (IRPI) study on Italian monuments included in the UNESCO World Heritage List has revealed that many are affected by geological, geomorphological, and engineering geological problems. These monuments are static entities set in an environment that often manifests highly dynamic processes. As part of the efforts to protect sites of cultural and natural heritage, this study has applied a preliminary and empirical Geographical Information System-based method developed to characterize the environmental hazards at the sites where the monuments are located. Because the study of hydrogeological degradation falls within the province of IRPI, this hazard zoning focuses on river and mountain slope dynamics specifically concerning landslides and floods.  相似文献   

Kinematic and geochronological constraints on shear deformation in the Ferriere-Mollières shear zone (Argentera-Mercantour Massif,Western Alps): implications for the evolution of the Southern European Variscan Belt     

Simonetti  Matteo  Carosi  Rodolfo  Montomoli  Chiara  Langone  Antonio  D’Addario  Enrico  Mammoliti  Elisa 《International Journal of Earth Sciences》2018,107(6):2163-2189

International Journal of Earth Sciences - In the Western Alps, a steeply dipping km-scale shear zone (the Ferriere-Mollières shear zone) cross-cuts Variscan migmatites in the...  相似文献   

Temporal trends in extreme rainfall intensity and erosivity in the Mediterranean region: a case study in southern Tuscany,Italy   总被引：2，自引：0，他引：2  

Chiara Vallebona  Elisa Pellegrino  Paolo Frumento  Enrico Bonari 《Climatic change》2015,128(1-2):139-151

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Active hydrothermal fluids circulation triggering small-scale collapse events: the case of the 2001–2002 fissure in the Lakki Plain (Nisyros Island,Aegean Sea,Greece)     

Stefania Venturi  Franco Tassi  Orlando Vaselli  Georges E. Vougioukalakis  Heba Rashed  Christos Kanellopoulos  Chiara Caponi  Francesco Capecchiacci  Jacopo Cabassi  Andrea Ricci  Luciano Giannini 《Natural Hazards》2018,90(2):601-621

Rip currents are fast moving, offshore flows that have the ability to move even the strongest swimmers into deeper waters. Miami Beach, Florida is one of the most visited beaches in the USA and a sought after destination for citizens and international tourists alike. It is also known to be a rip current “hot spot.” These factors greatly increase the risk of drowning; however, no previous research has focused on beachgoer perception of rip-related risks in South Florida. Over a 12-month period, 203 public surveys were collected to determine the rip current knowledge of beachgoers at Miami Beach based on factors such as swimming ability and frequency of beach visits. The responses were analyzed by constructing a normalized component factor to determine the respondent’s comprehensive knowledge of rips, and multiple regression models were used to assess the net influences of sociodemographic and behavioral characteristics on the responses. A significant proportion of the survey respondents showed insufficient knowledge, indicating they are at risk of drowning in a rip current. Frequent beachgoer’s exposure to the beach environment, maturation, and nativity is identified as the main contributors to knowledge net of other sociodemographic compositions. The most at-risk groups were determined to be young adults, foreign tourists, poor swimmers, and those who infrequently visited the beach. Miami Beach needs to initiate a rip current safety campaign to target these at-risk beachgoers, where interventions beyond familial and educational institutions should be introduced.  相似文献   

Quantitative risk analysis for hyperconcentrated flows in Nocera Inferiore (southern Italy)     

Ferlisi  Settimio  De Chiara  Giovanna  Cascini  Leonardo 《Natural Hazards》2015,77(1):89-100

This paper reports on a quantitative estimation of the risk to residents at the toe of Mount Albino, a carbonatic relief covered by shallow deposits of pyroclastic soils, which threatens the municipality of Nocera Inferiore (southern Italy). The quantitative risk analysis (QRA) focuses on one type of mass transport phenomena typical for the context at hand, namely the hyperconcentrated flows. The methodological approach includes three main steps: hazard analysis, consequence analysis and risk estimation. Based on historical incident data, the hazard analysis makes use of a high-resolution digital terrain model and advanced models that incorporate relevant geological and geotechnical input data collected via in situ investigations and laboratory tests. The consequence analysis takes into account information on the exposed persons (age, gender) and their vulnerability. The estimated risk to life is calculated at the individual level (risk to the average and most exposed person). The reported procedure is one of the first QRA’s applications to instabilities which potentially affect natural slopes in Italy, and it was successfully used as technical basis for a public participatory process in Nocera Inferiore, designed and developed to support decisions about risk mitigation measures.

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The Role of a Macroalgal Covering Event on the Microphytobenthos Community in Intertidal Sediment (Marano Lagoon, Northern Adriatic Sea)   总被引：1，自引：0，他引：1  

Elisabetta Sdrigotti  Chiara Welker 《Marine Ecology》2002,23(S1):370-383

Abstract. This study examines the variation in microphytobenthos structure and functioning in an intertidal lagoon during a macroalgal covering event. Multivariate techniques, applied on the recorded data, highlighted a clear seasonal pattern except for the July sample. The sudden macroalgae ( Cladophora sp.) development, which occurred in that month, enabled us to identify the massive covering as a disturbance factor on the benthic ecosystem. This biotic anomaly affected benthic microalgal production and community respiration, shifting the ecosystem from a highly photoautotrophic to an heterotrophic condition as shown by the BTS Index. This trophic index is therefore a useful tool for identifying episodic stress events mainly in intertidal habitats.  相似文献   

Multistage Metamorphic Evolution and P-T-t Path of High-T Eclogite from the North Dabie Complex Zone during Continental Subduction and Exhumation     

LIU Yican  DENG Liangpeng  GU Xiaofeng  GROPPO Chiar  and ROLFO Franco 《《地质学报》英文版》2016,90(2):759-760

正Objective High-T eclogites from the North Dabie complex zone(NDZ),central China underwent a complex metamorphic evolution involved in ultrahigh-pressure(UHP)and highpressure eclogite-facies metamorphism,and subsequent  相似文献   

Quaternary adakite—Nb-enriched basalt association in the western Trans-Mexican Volcanic Belt: is there any slab melt evidence?     

Chiara M. Petrone  Luca Ferrari 《Contributions to Mineralogy and Petrology》2008,156(1):73-86

A spatial and temporal association between adakitic rocks and Nb-enriched basalts (NEB) is recognised for the first time in the western sector of the Trans-Mexican Volcanic Belt in the San Pedro–Cerro Grande Volcanic Complex (SCVC). The SCVC is composed of subalkalic intermediate to felsic rocks, spanning in composition from high-silica andesites to rhyolites, and by the young transitional hawaiite and mugearite lavas of Amado Nervo shield volcano. Intermediate to felsic rocks of the SCVC show many geochemical characteristics of typical adakites, such as high Sr/Y ratios (up to 180) and low Y (<18 ppm) and Yb contents. Mafic Amado Nervo rocks have high TiO₂ (1.5–2.3 wt%), Nb (14–27 ppm), Nb/La (0.5–0.9) and high absolute abundances of HFSE similar to those shown by NEB. However, the Sr and Nd isotopic signature of SCVC rocks is different from that shown by typical adakites and NEB. Although the adakites–NEB association has been traditionally considered as a strong evidence of slab-melting, we suggest that other processes can lead to its generation. Here, we show that parental magmas of adakitic rocks of the SCVC derive their adakitic characteristic from high-pressure crystal fractionation processes of garnet, amphibole and pyroxene of a normal arc basalt. On the other hand, Amado Nervo Na-alkaline parental magmas have been generated by sediment melting plus MORB-fluid flux melting of a heterogeneous mantle wedge, consisting of a mixture of depleted and an enriched mantle sources (90DM + 10EM). We cannot exclude a contribution to the subduction component of slab melts, because the component signature is dominated by sediment melt, but we argue that caution is needed in interpreting the adakites–NEB association in a genetic sense.  相似文献   

Strain analysis and vorticity of flow in the Northern Sardinian Variscan Belt: Recognition of a partitioned oblique deformation event   总被引：1，自引：0，他引：1  

D. Iacopini  R. Carosi  C. Montomoli  C.W. Passchier 《Tectonophysics》2008,446(1-4):77-96

A field example of strain partitioning has been analysed along the Nurra–Asinara transect of the NW Sardinian Variscan chain (Italy). The section in the Nurra–Asinara area is in a continuous sequence of tectono-metamorphic complexes made of low- to high-grade metamorphic rocks affected by a polyphase tectonic history. The principal fabric of the area is controlled by a D2 progressive deformation phase in which the strain is partitioned into folds and shear zone domains. The D2 stretching lineation and shear sense show a clear change from south to north. The principal meso- and micro-structures, vorticity gauges and a quantitative kinematic analysis of local strain suggest that the D2 kinematic history could be envisaged as an oblique heterogeneous deformation similar to the transpressive systems described in ancient and modern settings elsewhere. Using a simple kinematic model we also propose that both a transpressive system followed by “thrusting” or a partitioned transpressive system could be responsible for the fabric distribution and strain accumulation described in the study transect.  相似文献